[robert mitchell]

Does anybody know what the summer/winter switch actually does ?  i have not noticed any difference in heat on either setting.

[Splash & dash]

Does anybody know what the summer/winter switch actually does ?  i have not noticed any difference in heat on either setting.

Summer setting will give more heat  winter  setting reduced heat

[NWH]

No different to the Grippa heater on mine you just turn it down to minimum on each of the heat exchangers externally  it’s still smokes like a bonfire on the glass not as hot though.

[dazmond]

Does anybody know what the summer/winter switch actually does ?  i have not noticed any difference in heat on either setting.

Summer setting will give more heat  winter  setting reduced heat

shouldnt that be the other way round?less heat in the warmer months and hotter in the winter months?as a lot of heat is lost from the hose on a cold day in winter.....in summer it can be uncomfortable to hold the hose because its that hot on a warm day that i sometimes turn my boiler off at lunchtime......i can get up to  70c at the brush head in summer!

[robert mitchell]

Does anybody know what the summer/winter switch actually does ?  i have not noticed any difference in heat on either setting.

Summer setting will give more heat  winter  setting reduced heat

shouldnt that be the other way round?less heat in the warmer months and hotter in the winter months?as a lot of heat is lost from the hose on a cold day in winter.....in summer it can be uncomfortable to hold the hose because its that hot on a warm day that i sometimes turn my boiler off at lunchtime......i can get up to  70c at the brush head in summer!

This is what im trying to work out , my system has temp gauge and seems to get up to 80c on either setting.

[Ched]

Does anybody know what the summer/winter switch actually does ?  i have not noticed any difference in heat on either setting.

Summer setting will give more heat  winter  setting reduced heat

shouldnt that be the other way round?less heat in the warmer months and hotter in the winter months?as a lot of heat is lost from the hose on a cold day in winter.....in summer it can be uncomfortable to hold the hose because its that hot on a warm day that i sometimes turn my boiler off at lunchtime......i can get up to  70c at the brush head in summer!

Maybe it's to try and stop cracking windows as in winter glass colder so bigger temp differential.

[dd]

Does anybody know what the summer/winter switch actually does ?  i have not noticed any difference in heat on either setting.

Summer setting will give more heat  winter  setting reduced heat

shouldnt that be the other way round?less heat in the warmer months and hotter in the winter months?as a lot of heat is lost from the hose on a cold day in winter.....in summer it can be uncomfortable to hold the hose because its that hot on a warm day that i sometimes turn my boiler off at lunchtime......i can get up to  70c at the brush head in summer!

No. Less heat in winter as you do not want to crack glass. I think your heater will chuck out more heat in winter now Daz, as it should now be working more efficiently.

[NWH]

I know they lose a bit of heat Daz but mine has been kettle hot I’ve turned it minimum last week or so,when you put one of those heaters in a Transporter they work far better 🤣🤣🤣🤣

[robert mitchell]

Does anybody know what the summer/winter switch actually does ?  i have not noticed any difference in heat on either setting.

Summer setting will give more heat  winter  setting reduced heat

shouldnt that be the other way round?less heat in the warmer months and hotter in the winter months?as a lot of heat is lost from the hose on a cold day in winter.....in summer it can be uncomfortable to hold the hose because its that hot on a warm day that i sometimes turn my boiler off at lunchtime......i can get up to  70c at the brush head in summer!

No. Less heat in winter as you do not want to crack glass. I think your heater will chuck out more heat in winter now Daz, as it should now be working more efficiently.

Is that official from the ionics thermopure handbook or are you just assuming?

[dd]

Does anybody know what the summer/winter switch actually does ?  i have not noticed any difference in heat on either setting.

Summer setting will give more heat  winter  setting reduced heat

shouldnt that be the other way round?less heat in the warmer months and hotter in the winter months?as a lot of heat is lost from the hose on a cold day in winter.....in summer it can be uncomfortable to hold the hose because its that hot on a warm day that i sometimes turn my boiler off at lunchtime......i can get up to  70c at the brush head in summer!

No. Less heat in winter as you do not want to crack glass. I think your heater will chuck out more heat in winter now Daz, as it should now be working more efficiently.

Is that official from the ionics thermopure handbook or are you just assuming?

I used to have 5kw Webasto from Pure Freedom. It is based on the understanding I had from that (discussion with PF comparing there unit with Ionics). I am 95% sure it is true. You do not want to expose cold glass to sudden high temperature. If you find no difference on either setting maybe the switch is faulty.

[robert mitchell]

Does anybody know what the summer/winter switch actually does ?  i have not noticed any difference in heat on either setting.

Summer setting will give more heat  winter  setting reduced heat

shouldnt that be the other way round?less heat in the warmer months and hotter in the winter months?as a lot of heat is lost from the hose on a cold day in winter.....in summer it can be uncomfortable to hold the hose because its that hot on a warm day that i sometimes turn my boiler off at lunchtime......i can get up to  70c at the brush head in summer!

No. Less heat in winter as you do not want to crack glass. I think your heater will chuck out more heat in winter now Daz, as it should now be working more efficiently.

Is that official from the ionics thermopure handbook or are you just assuming?

I used to have 5kw Webasto from Pure Freedom. It is based on the understanding I had from that (discussion with PF comparing there unit with Ionics). I am 95% sure it is true. You do not want to expose cold glass to sudden high temperature. If you find no difference on either setting maybe the switch is faulty.

I have been using hot for around three years and a bit now , my first one was a purefreedom on , always had it as hot as possible and never cracked a window ,

[NWH]

That Squeaky clean did a test  on glass units outside covered in snow and frost with a kettle of hot water,you can’t test glass like that unless it’s in a frame and if there is any imperfections in the glass it will find them and crack I’ve done a few.
You have to be a bit sensible it will crack glass even in summer months if like I say the glass already has a crack or damage,I cracked a newly installed PVC unit 130 notes in the middle of summer still love hot though 👌

[dazmond]

in winter

1.starting temperature of your tank water is much lower before heating
2.you lose A LOT of heat from the hose with 100m on freezing ground

so it stands to reason to have it on full heat setting during the winter months

in summer

1.starting temperature of your tank water is much higher before heating
2.lots of heat is retained in the hose

so it stands to reason to turn it down in summer

i just leave mine on full heat setting all year round.....the mixer valves are rubbish anyway on these heaters IMO.....

[NWH]

Now you’ve got a proper heater you might think again this time next week m8,honestly I filled a plastic bottle up last week and it deformed it was too hot to hold first thing in the morning, lately it has been very cold where I’ve been you need to clean quickly and rinse as you go if it’s on full heat it definitely crack glass I’ve been getting it up to temperature and then turn it off for the first couple of jobs out in the sticks then back on.

[dazmond]

Now you’ve got a proper heater you might think again this time next week m8,honestly I filled a plastic bottle up last week and it deformed it was too hot to hold first thing in the morning, lately it has been very cold where I’ve been you need to clean quickly and rinse as you go if it’s on full heat it definitely crack glass I’ve been getting it up to temperature and then turn it off for the first couple of jobs out in the sticks then back on.

personally i think your heater runs too hot you ve even admitted it yourself before now mate.....

who cracks glass in the middle of summer on a hot day?....yep nigel does....thats a sure sign your heater is ridiculously hot IMO.....


like ive said before i lose AT LEAST 20c temperature wise with all my hose off the reel ON A COLD DAY....so today my coiled reel was reading 62c....so with 100m out itll be down to 42 at brush head...even less than that on very cold days which is fine for cleaning and less risk of cracking a pane....in summer it can get up to 70c at the brush head!

[dd]

Conversation I had with PF was that there heater was better then Ionics because the Ionic heater only had winter and summer setting whereas the PF could be adjusted to give a wider range of temp setting. I would not use PF again due to issues I had.

I understood the winter setting to be the minimum. I also had a demo from Ionics around 15 years ago. I could be wrong. If you want to be sure just give them a call.

[Spruce]

in winter

1.starting temperature of your tank water is much lower before heating
2.you lose A LOT of heat from the hose with 100m on freezing ground

so it stands to reason to have it on full heat setting during the winter months

in summer

1.starting temperature of your tank water is much higher before heating
2.lots of heat is retained in the hose

so it stands to reason to turn it down in summer

i just leave mine on full heat setting all year round.....the mixer valves are rubbish anyway on these heaters IMO.....

Daz,
When you get your heater serviced please can you ask what terminal 7 in the plug does. It has a green wire.

From what I see from the wiring diagram and a note in the instruction manual, applying power (12v+) to that green cable changes the heat mode output on the Thermo Pro 90. In a vehicle application this cable would be connected to a positive on the ignition switch.

10.5
Setting control temperatures of Thermo Pro 90
When the signal “Engine on”/”Engine off” (Terminal D+) are connected to
the control unit connector X8, contact 7, different control thresholds are effective.

                                                           Nominal temperature on sensor     Regulating pause       Switch on again after regulating pause

“Engine on”                                                            65 °C                                                        75 °C                                               60 °C
“Engine off”                                                           80 °C                                                        90 °C                                                75 °C

If the terminal D+ signal is not applied, the temperatures are the same as those at “Engine off”.
The selected regulating pause temperature of the heater should be lower than the opening temperature of the radiator thermostat.

My heater gets up to 80 degrees plus.

Setting a diesel heater with a temperature/thermostatic control valve on the heat exchanger won't work with lower temps as the heater will switch off and then on to often during the day.
 A max of 65 degrees would probably work on an Ionic unit as they don't have a temperature control valve. The pump runs continually and the moment you stop water to the brush head with a tap/Univalve the hot water diverts to the tank via a pressure relief valve. (The pressure relief valve is set to 'blow off' at 65psi.)

With an Ionics unit you get what the units temperature is in the internal water jacket. If its 80 degrees then that's what the temp is of the water leaving your heater. If the switch is on then you get 65 degrees or less.

At least with a temperature control valve you can regulate that as DD says.

Each system has its pros and cons.

[dazmond]

sorry spruce ive already had a new burner and glow pin fitted today (they fitted a faulty glow pin yesterday!)so i had to go back today once they got the new pin...they changed it in 20 mins...its working great now...they also changed some pipework as i had a kink in my hose going into the heat exchanger which they reckon caused lots of carbon build up in the burner...they said they ve never seen a burner so fouled up!

[NWH]

You’ll still crack glass at 40 degrees if the glass is already damaged even new glass can have hairline cracks that start beneath the seals,the other cracking scenario is when the pane of glass has no flex within the unit say a painted in or a pane of glass that’s sealed in tight with putty.
The art to cleaning with hot water is to be quicker on the glass if you clean like some of these Idiots that stand there rinsing till the cows start moaning you’ll crack a lot of windows,with hot water you don’t need to constantly rinse that’s one of the benefits especially on regular stuff you are basically just colouring in windows in seconds and I mean seconds,some windows 3-4-5 windows on a bay are cleaned in and around 30-40 seconds if you know what you are doing.

[NWH]

They will always change the glow pin with a burner.

[Spruce]

in winter

1.starting temperature of your tank water is much lower before heating
2.you lose A LOT of heat from the hose with 100m on freezing ground

so it stands to reason to have it on full heat setting during the winter months

in summer

1.starting temperature of your tank water is much higher before heating
2.lots of heat is retained in the hose

so it stands to reason to turn it down in summer

i just leave mine on full heat setting all year round.....the mixer valves are rubbish anyway on these heaters IMO.....

Daz,
When you get your heater serviced please can you ask what terminal 7 in the plug does. It has a green wire.

From what I see from the wiring diagram and a note in the instruction manual, applying power (12v+) to that green cable changes the heat mode output on the Thermo Pro 90. In a vehicle application this cable would be connected to a positive on the ignition switch.

10.5
Setting control temperatures of Thermo Pro 90
When the signal “Engine on”/”Engine off” (Terminal D+) are connected to
the control unit connector X8, contact 7, different control thresholds are effective.

                                                           Nominal temperature on sensor     Regulating pause       Switch on again after regulating pause

“Engine on”                                                            65 °C                                                        75 °C                                               60 °C
“Engine off”                                                           80 °C                                                        90 °C                                                75 °C

If the terminal D+ signal is not applied, the temperatures are the same as those at “Engine off”.
The selected regulating pause temperature of the heater should be lower than the opening temperature of the radiator thermostat.

My heater gets up to 80 degrees plus.

Setting a diesel heater with a temperature/thermostatic control valve on the heat exchanger won't work with lower temps as the heater will switch off and then on to often during the day.
 A max of 65 degrees would probably work on an Ionic unit as they don't have a temperature control valve. The pump runs continually and the moment you stop water to the brush head with a tap/Univalve the hot water diverts to the tank via a pressure relief valve. (The pressure relief valve is set to 'blow off' at 65psi.)

With an Ionics unit you get what the units temperature is in the internal water jacket. If its 80 degrees then that's what the temp is of the water leaving your heater. If the switch is on then you get 65 degrees or less.

At least with a temperature control valve you can regulate that as DD says.

Each system has its pros and cons.

To late. Daz has had it serviced

[robert mitchell]

in winter

1.starting temperature of your tank water is much lower before heating
2.you lose A LOT of heat from the hose with 100m on freezing ground

so it stands to reason to have it on full heat setting during the winter months

in summer

1.starting temperature of your tank water is much higher before heating
2.lots of heat is retained in the hose

so it stands to reason to turn it down in summer

i just leave mine on full heat setting all year round.....the mixer valves are rubbish anyway on these heaters IMO.....

Daz,
When you get your heater serviced please can you ask what terminal 7 in the plug does. It has a green wire.

From what I see from the wiring diagram and a note in the instruction manual, applying power (12v+) to that green cable changes the heat mode output on the Thermo Pro 90. In a vehicle application this cable would be connected to a positive on the ignition switch.

10.5
Setting control temperatures of Thermo Pro 90
When the signal “Engine on”/”Engine off” (Terminal D+) are connected to
the control unit connector X8, contact 7, different control thresholds are effective.

                                                           Nominal temperature on sensor     Regulating pause       Switch on again after regulating pause

“Engine on”                                                            65 °C                                                        75 °C                                               60 °C
“Engine off”                                                           80 °C                                                        90 °C                                                75 °C

If the terminal D+ signal is not applied, the temperatures are the same as those at “Engine off”.
The selected regulating pause temperature of the heater should be lower than the opening temperature of the radiator thermostat.

My heater gets up to 80 degrees plus.

Setting a diesel heater with a temperature/thermostatic control valve on the heat exchanger won't work with lower temps as the heater will switch off and then on to often during the day.
 A max of 65 degrees would probably work on an Ionic unit as they don't have a temperature control valve. The pump runs continually and the moment you stop water to the brush head with a tap/Univalve the hot water diverts to the tank via a pressure relief valve. (The pressure relief valve is set to 'blow off' at 65psi.)

With an Ionics unit you get what the units temperature is in the internal water jacket. If its 80 degrees then that's what the temp is of the water leaving your heater. If the switch is on then you get 65 degrees or less.

At least with a temperature control valve you can regulate that as DD says.

Each system has its pros and cons.

Cheers spruce , i think i understand it now .

Currently trying to make sense of the wiring diagrams as i am going to fit the new thermo pro 90 in place of my old thermo 90 s .........but the wiring loom all has to be replaced as does the fuel pump as they are different on the new heater.

[robert mitchell]

You’ll still crack glass at 40 degrees if the glass is already damaged even new glass can have hairline cracks that start beneath the seals,the other cracking scenario is when the pane of glass has no flex within the unit say a painted in or a pane of glass that’s sealed in tight with putty.
The art to cleaning with hot water is to be quicker on the glass if you clean like some of these Idiots that stand there rinsing till the cows start moaning you’ll crack a lot of windows,with hot water you don’t need to constantly rinse that’s one of the benefits especially on regular stuff you are basically just colouring in windows in seconds and I mean seconds,some windows 3-4-5 windows on a bay are cleaned in and around 30-40 seconds if you know what you are doing.

You da man !

[NWH]

Yo da man Christ you’ll be banging on about coronavirus next like you’re other bully m8 on here get some hot water,scrubbing glass will be a distant memory.

[Spruce]

in winter

1.starting temperature of your tank water is much lower before heating
2.you lose A LOT of heat from the hose with 100m on freezing ground

so it stands to reason to have it on full heat setting during the winter months

in summer

1.starting temperature of your tank water is much higher before heating
2.lots of heat is retained in the hose

so it stands to reason to turn it down in summer

i just leave mine on full heat setting all year round.....the mixer valves are rubbish anyway on these heaters IMO.....

Daz,
When you get your heater serviced please can you ask what terminal 7 in the plug does. It has a green wire.

From what I see from the wiring diagram and a note in the instruction manual, applying power (12v+) to that green cable changes the heat mode output on the Thermo Pro 90. In a vehicle application this cable would be connected to a positive on the ignition switch.

10.5
Setting control temperatures of Thermo Pro 90
When the signal “Engine on”/”Engine off” (Terminal D+) are connected to
the control unit connector X8, contact 7, different control thresholds are effective.

                                                           Nominal temperature on sensor     Regulating pause       Switch on again after regulating pause

“Engine on”                                                            65 °C                                                        75 °C                                               60 °C
“Engine off”                                                           80 °C                                                        90 °C                                                75 °C

If the terminal D+ signal is not applied, the temperatures are the same as those at “Engine off”.
The selected regulating pause temperature of the heater should be lower than the opening temperature of the radiator thermostat.

My heater gets up to 80 degrees plus.

Setting a diesel heater with a temperature/thermostatic control valve on the heat exchanger won't work with lower temps as the heater will switch off and then on to often during the day.
 A max of 65 degrees would probably work on an Ionic unit as they don't have a temperature control valve. The pump runs continually and the moment you stop water to the brush head with a tap/Univalve the hot water diverts to the tank via a pressure relief valve. (The pressure relief valve is set to 'blow off' at 65psi.)

With an Ionics unit you get what the units temperature is in the internal water jacket. If its 80 degrees then that's what the temp is of the water leaving your heater. If the switch is on then you get 65 degrees or less.

At least with a temperature control valve you can regulate that as DD says.

Each system has its pros and cons.

Cheers spruce , i think i understand it now .

Currently trying to make sense of the wiring diagrams as i am going to fit the new thermo pro 90 in place of my old thermo 90 s .........but the wiring loom all has to be replaced as does the fuel pump as they are different on the new heater.

If you have a Thermo 90ST then the wiring looms are the same. You just have to replace the fuel pump and fuel pump supply cable. I've done that.

The Thermo 90S has the cables come from the bottom of the control panel and has a different connector, so yes, if that's the unit you have then you would need to replace the wiring harness as well.

[robert mitchell]

Yo da man Christ you’ll be banging on about coronavirus next like you’re other bully m8 on here get some hot water,scrubbing glass will be a distant memory.

I have had hot water for years you donut 🍩

[robert mitchell]

in winter

1.starting temperature of your tank water is much lower before heating
2.you lose A LOT of heat from the hose with 100m on freezing ground

so it stands to reason to have it on full heat setting during the winter months

in summer

1.starting temperature of your tank water is much higher before heating
2.lots of heat is retained in the hose

so it stands to reason to turn it down in summer

i just leave mine on full heat setting all year round.....the mixer valves are rubbish anyway on these heaters IMO.....

Daz,
When you get your heater serviced please can you ask what terminal 7 in the plug does. It has a green wire.

From what I see from the wiring diagram and a note in the instruction manual, applying power (12v+) to that green cable changes the heat mode output on the Thermo Pro 90. In a vehicle application this cable would be connected to a positive on the ignition switch.

10.5
Setting control temperatures of Thermo Pro 90
When the signal “Engine on”/”Engine off” (Terminal D+) are connected to
the control unit connector X8, contact 7, different control thresholds are effective.

                                                           Nominal temperature on sensor     Regulating pause       Switch on again after regulating pause

“Engine on”                                                            65 °C                                                        75 °C                                               60 °C
“Engine off”                                                           80 °C                                                        90 °C                                                75 °C

If the terminal D+ signal is not applied, the temperatures are the same as those at “Engine off”.
The selected regulating pause temperature of the heater should be lower than the opening temperature of the radiator thermostat.

My heater gets up to 80 degrees plus.

Setting a diesel heater with a temperature/thermostatic control valve on the heat exchanger won't work with lower temps as the heater will switch off and then on to often during the day.
 A max of 65 degrees would probably work on an Ionic unit as they don't have a temperature control valve. The pump runs continually and the moment you stop water to the brush head with a tap/Univalve the hot water diverts to the tank via a pressure relief valve. (The pressure relief valve is set to 'blow off' at 65psi.)

With an Ionics unit you get what the units temperature is in the internal water jacket. If its 80 degrees then that's what the temp is of the water leaving your heater. If the switch is on then you get 65 degrees or less.

At least with a temperature control valve you can regulate that as DD says.

Each system has its pros and cons.

Cheers spruce , i think i understand it now .

Currently trying to make sense of the wiring diagrams as i am going to fit the new thermo pro 90 in place of my old thermo 90 s .........but the wiring loom all has to be replaced as does the fuel pump as they are different on the new heater.

If you have a Thermo 90ST then the wiring looms are the same. You just have to replace the fuel pump and fuel pump supply cable. I've done that.

The Thermo 90S has the cables come from the bottom of the control panel and has a different connector, so yes, if that's the unit you have then you would need to replace the wiring harness as well.

Hi Spruce ,

No , I have the newest version which is the thermo 90 Pro , which is different again , although on first inspection the fuel pump wiring plugs look identical , the rest of the loom is very different though !

From what I have gathered so far I think I only have to connect the 12 pin plug to the battery ( through a fuse of course ) , plug in the fuel wiring and plug the on / off switch into the loom ........unless I’m missing something?

Obviously will change the exhaust and inlet and the fuel pump itself .

[Spruce]

in winter

1.starting temperature of your tank water is much lower before heating
2.you lose A LOT of heat from the hose with 100m on freezing ground

so it stands to reason to have it on full heat setting during the winter months

in summer

1.starting temperature of your tank water is much higher before heating
2.lots of heat is retained in the hose

so it stands to reason to turn it down in summer

i just leave mine on full heat setting all year round.....the mixer valves are rubbish anyway on these heaters IMO.....

Daz,
When you get your heater serviced please can you ask what terminal 7 in the plug does. It has a green wire.

From what I see from the wiring diagram and a note in the instruction manual, applying power (12v+) to that green cable changes the heat mode output on the Thermo Pro 90. In a vehicle application this cable would be connected to a positive on the ignition switch.

10.5
Setting control temperatures of Thermo Pro 90
When the signal “Engine on”/”Engine off” (Terminal D+) are connected to
the control unit connector X8, contact 7, different control thresholds are effective.

                                                           Nominal temperature on sensor     Regulating pause       Switch on again after regulating pause

“Engine on”                                                            65 °C                                                        75 °C                                               60 °C
“Engine off”                                                           80 °C                                                        90 °C                                                75 °C

If the terminal D+ signal is not applied, the temperatures are the same as those at “Engine off”.
The selected regulating pause temperature of the heater should be lower than the opening temperature of the radiator thermostat.

My heater gets up to 80 degrees plus.

Setting a diesel heater with a temperature/thermostatic control valve on the heat exchanger won't work with lower temps as the heater will switch off and then on to often during the day.
 A max of 65 degrees would probably work on an Ionic unit as they don't have a temperature control valve. The pump runs continually and the moment you stop water to the brush head with a tap/Univalve the hot water diverts to the tank via a pressure relief valve. (The pressure relief valve is set to 'blow off' at 65psi.)

With an Ionics unit you get what the units temperature is in the internal water jacket. If its 80 degrees then that's what the temp is of the water leaving your heater. If the switch is on then you get 65 degrees or less.

At least with a temperature control valve you can regulate that as DD says.

Each system has its pros and cons.

Cheers spruce , i think i understand it now .

Currently trying to make sense of the wiring diagrams as i am going to fit the new thermo pro 90 in place of my old thermo 90 s .........but the wiring loom all has to be replaced as does the fuel pump as they are different on the new heater.

If you have a Thermo 90ST then the wiring looms are the same. You just have to replace the fuel pump and fuel pump supply cable. I've done that.

The Thermo 90S has the cables come from the bottom of the control panel and has a different connector, so yes, if that's the unit you have then you would need to replace the wiring harness as well.

Hi Spruce ,

No , I have the newest version which is the thermo 90 Pro , which is different again , although on first inspection the fuel pump wiring plugs look identical , the rest of the loom is very different though !

From what I have gathered so far I think I only have to connect the 12 pin plug to the battery ( through a fuse of course ) , plug in the fuel wiring and plug the on / off switch into the loom ........unless I’m missing something?

Obviously will change the exhaust and inlet and the fuel pump itself .

I was able to replace a Thermo 90ST with a Thermo Pro 90 without changing the wiring harness. They tell you to change the fuel pump to a DP42 which has a different connector to the older DP30 pump. It also seems to be much quieter when running.  I bought a new harness with cable that had the correct plug for the new pump and purchased a separate plug for the control panel and fitted it on. I had to buy the pump from Turkey as no one had stock of them in the UK.

The Pro 90 does seem to have a different diagnostic plug but that won't stop the heater from working. For me the red cable was batt positive, brown batt negative, black positive from on/off switch and white the led info light. There are a couple of other wires that aren't used, grey, blue, green/white and violet.  They are used for other accessories when used as a engine preheater for example. (One of them will activate the fan inside the cabin when the coolant temperature reaches 30 degrees. Warm air is then directed to the windscreen if set up that way to defrost it.)

Depending on the application there are different wiring harness with wires and connectors for a timer and or thermostat. The Webasto supplier who works out of Turkey will add additional features to the loom to your requirements.

If you are going from a Thermo 90S to a Thermo Pro 90 then the wiring harness is different.

[robert mitchell]

in winter

1.starting temperature of your tank water is much lower before heating
2.you lose A LOT of heat from the hose with 100m on freezing ground

so it stands to reason to have it on full heat setting during the winter months

in summer

1.starting temperature of your tank water is much higher before heating
2.lots of heat is retained in the hose

so it stands to reason to turn it down in summer

i just leave mine on full heat setting all year round.....the mixer valves are rubbish anyway on these heaters IMO.....

Daz,
When you get your heater serviced please can you ask what terminal 7 in the plug does. It has a green wire.

From what I see from the wiring diagram and a note in the instruction manual, applying power (12v+) to that green cable changes the heat mode output on the Thermo Pro 90. In a vehicle application this cable would be connected to a positive on the ignition switch.

10.5
Setting control temperatures of Thermo Pro 90
When the signal “Engine on”/”Engine off” (Terminal D+) are connected to
the control unit connector X8, contact 7, different control thresholds are effective.

                                                           Nominal temperature on sensor     Regulating pause       Switch on again after regulating pause

“Engine on”                                                            65 °C                                                        75 °C                                               60 °C
“Engine off”                                                           80 °C                                                        90 °C                                                75 °C

If the terminal D+ signal is not applied, the temperatures are the same as those at “Engine off”.
The selected regulating pause temperature of the heater should be lower than the opening temperature of the radiator thermostat.

My heater gets up to 80 degrees plus.

Setting a diesel heater with a temperature/thermostatic control valve on the heat exchanger won't work with lower temps as the heater will switch off and then on to often during the day.
 A max of 65 degrees would probably work on an Ionic unit as they don't have a temperature control valve. The pump runs continually and the moment you stop water to the brush head with a tap/Univalve the hot water diverts to the tank via a pressure relief valve. (The pressure relief valve is set to 'blow off' at 65psi.)

With an Ionics unit you get what the units temperature is in the internal water jacket. If its 80 degrees then that's what the temp is of the water leaving your heater. If the switch is on then you get 65 degrees or less.

At least with a temperature control valve you can regulate that as DD says.

Each system has its pros and cons.

Cheers spruce , i think i understand it now .

Currently trying to make sense of the wiring diagrams as i am going to fit the new thermo pro 90 in place of my old thermo 90 s .........but the wiring loom all has to be replaced as does the fuel pump as they are different on the new heater.

If you have a Thermo 90ST then the wiring looms are the same. You just have to replace the fuel pump and fuel pump supply cable. I've done that.

The Thermo 90S has the cables come from the bottom of the control panel and has a different connector, so yes, if that's the unit you have then you would need to replace the wiring harness as well.

Hi Spruce ,

No , I have the newest version which is the thermo 90 Pro , which is different again , although on first inspection the fuel pump wiring plugs look identical , the rest of the loom is very different though !

From what I have gathered so far I think I only have to connect the 12 pin plug to the battery ( through a fuse of course ) , plug in the fuel wiring and plug the on / off switch into the loom ........unless I’m missing something?

Obviously will change the exhaust and inlet and the fuel pump itself .

I was able to replace a Thermo 90ST with a Thermo Pro 90 without changing the wiring harness. They tell you to change the fuel pump to a DP42 which has a different connector to the older DP30 pump. It also seems to be much quieter when running.  I bought a new harness with cable that had the correct plug for the new pump and purchased a separate plug for the control panel and fitted it on. I had to buy the pump from Turkey as no one had stock of them in the UK.

The Pro 90 does seem to have a different diagnostic plug but that won't stop the heater from working. For me the red cable was batt positive, brown batt negative, black positive from on/off switch and white the led info light. There are a couple of other wires that aren't used, grey, blue, green/white and violet.  They are used for other accessories when used as a engine preheater for example. (One of them will activate the fan inside the cabin when the coolant temperature reaches 30 degrees. Warm air is then directed to the windscreen if set up that way to defrost it.)

Depending on the application there are different wiring harness with wires and connectors for a timer and or thermostat. The Webasto supplier who works out of Turkey will add additional features to the loom to your requirements.

If you are going from a Thermo Pro 90 to a Thermo 90S then the wiring harness is different.

Cheers spruce ,

You were right about the fuel pump wiring , different plug at the pump end so replaced the loom  from pump to heater .

My Loom for the heater itself has just one 12 pin plug , a small four pin plug for a switch ( plug and play ) and another small four pin plug ( not sure what it does , maybe diagnostic) .

My switch hasn’t arrived yet , do you know if I can bridge 2 of the wires on the switch harness plug to test it ?

[robert mitchell]

My old one was a thermo 90 s not st .

[Spruce]

in winter

1.starting temperature of your tank water is much lower before heating
2.you lose A LOT of heat from the hose with 100m on freezing ground

so it stands to reason to have it on full heat setting during the winter months

in summer

1.starting temperature of your tank water is much higher before heating
2.lots of heat is retained in the hose

so it stands to reason to turn it down in summer

i just leave mine on full heat setting all year round.....the mixer valves are rubbish anyway on these heaters IMO.....

Daz,
When you get your heater serviced please can you ask what terminal 7 in the plug does. It has a green wire.

From what I see from the wiring diagram and a note in the instruction manual, applying power (12v+) to that green cable changes the heat mode output on the Thermo Pro 90. In a vehicle application this cable would be connected to a positive on the ignition switch.

10.5
Setting control temperatures of Thermo Pro 90
When the signal “Engine on”/”Engine off” (Terminal D+) are connected to
the control unit connector X8, contact 7, different control thresholds are effective.

                                                           Nominal temperature on sensor     Regulating pause       Switch on again after regulating pause

“Engine on”                                                            65 °C                                                        75 °C                                               60 °C
“Engine off”                                                           80 °C                                                        90 °C                                                75 °C

If the terminal D+ signal is not applied, the temperatures are the same as those at “Engine off”.
The selected regulating pause temperature of the heater should be lower than the opening temperature of the radiator thermostat.

My heater gets up to 80 degrees plus.

Setting a diesel heater with a temperature/thermostatic control valve on the heat exchanger won't work with lower temps as the heater will switch off and then on to often during the day.
 A max of 65 degrees would probably work on an Ionic unit as they don't have a temperature control valve. The pump runs continually and the moment you stop water to the brush head with a tap/Univalve the hot water diverts to the tank via a pressure relief valve. (The pressure relief valve is set to 'blow off' at 65psi.)

With an Ionics unit you get what the units temperature is in the internal water jacket. If its 80 degrees then that's what the temp is of the water leaving your heater. If the switch is on then you get 65 degrees or less.

At least with a temperature control valve you can regulate that as DD says.

Each system has its pros and cons.

Cheers spruce , i think i understand it now .

Currently trying to make sense of the wiring diagrams as i am going to fit the new thermo pro 90 in place of my old thermo 90 s .........but the wiring loom all has to be replaced as does the fuel pump as they are different on the new heater.

If you have a Thermo 90ST then the wiring looms are the same. You just have to replace the fuel pump and fuel pump supply cable. I've done that.

The Thermo 90S has the cables come from the bottom of the control panel and has a different connector, so yes, if that's the unit you have then you would need to replace the wiring harness as well.

Hi Spruce ,

No , I have the newest version which is the thermo 90 Pro , which is different again , although on first inspection the fuel pump wiring plugs look identical , the rest of the loom is very different though !

From what I have gathered so far I think I only have to connect the 12 pin plug to the battery ( through a fuse of course ) , plug in the fuel wiring and plug the on / off switch into the loom ........unless I’m missing something?

Obviously will change the exhaust and inlet and the fuel pump itself .

I was able to replace a Thermo 90ST with a Thermo Pro 90 without changing the wiring harness. They tell you to change the fuel pump to a DP42 which has a different connector to the older DP30 pump. It also seems to be much quieter when running.  I bought a new harness with cable that had the correct plug for the new pump and purchased a separate plug for the control panel and fitted it on. I had to buy the pump from Turkey as no one had stock of them in the UK.

The Pro 90 does seem to have a different diagnostic plug but that won't stop the heater from working. For me the red cable was batt positive, brown batt negative, black positive from on/off switch and white the led info light. There are a couple of other wires that aren't used, grey, blue, green/white and violet.  They are used for other accessories when used as a engine preheater for example. (One of them will activate the fan inside the cabin when the coolant temperature reaches 30 degrees. Warm air is then directed to the windscreen if set up that way to defrost it.)

Depending on the application there are different wiring harness with wires and connectors for a timer and or thermostat. The Webasto supplier who works out of Turkey will add additional features to the loom to your requirements.

If you are going from a Thermo Pro 90 to a Thermo 90S then the wiring harness is different.

Cheers spruce ,

You were right about the fuel pump wiring , different plug at the pump end so replaced the loom  from pump to heater .

My Loom for the heater itself has just one 12 pin plug , a small four pin plug for a switch ( plug and play ) and another small four pin plug ( not sure what it does , maybe diagnostic) .

My switch hasn’t arrived yet , do you know if I can bridge 2 of the wires on the switch harness plug to test it ?

I honestly don't know how they wire different plugs up.
The best thing is to wait intil it arrives and then see what you can from the different wiring diagrams for that heater.

As I've stated earlier, all I needed to get the heater in operation was those four wires, red, brown,  black and white.  If you have a Frostsat then the black wire connects to the blue from the frostat. White goes to the LED which lights up on starting/running and flashes up any fault codes. The other side of the LED goes to earth. Red is positive from the battery and brown negative.

There are some controllers that are timers as well. But I believe these wouldn't work for our application.

[robert mitchell]

Well that didn’t work , something else must need connecting other than power and the switch ......can’t for the life of me work out what though !

[robert mitchell]

Have had this up and running for a few months now , but the water now only gets to about 50c before hose ( just after heat exchanger ) where it used to get 80c with the old 90s .

Any ideas ?

[NWH]

New heat exchangers or burner then I’d do exchangers first though

[robert mitchell]

New heat exchangers or burner then I’d do exchangers first though

Don’t be daft , it was brand new a few months ago .

[NWH]

It hasn’t got flicked into winter mode has it.

[Spruce]

Have had this up and running for a few months now , but the water now only gets to about 50c before hose ( just after heat exchanger ) where it used to get 80c with the old 90s .

Any ideas ?

It would seem that the issue is in the heater itself. I would suggest a Webasto agent put it on his computer and try to diagnose the fault.
There is a water temperature sensor on the heater outlet which could be faulty.

There is apparently a low temperature Thermo Pro 90 12v reference number 9030723C. I can't find any specs on it.

[Splash & dash]

I think Nigel might be right the switch has been hit and put it into winter mode that reduces the water temperature , it’s easy dine it happens to ours now and again when switching on  the fill valve .

[NWH]

That’s what’s happened it’s in winter mode

[Spruce]

I think Nigel might be right the switch has been hit and put it into winter mode that reduces the water temperature , it’s easy dine it happens to ours now and again when switching on  the fill valve .

If it is the switch then there is also the possibility that the switch is faulty. If switching the switch doesn't do anything, then I would try removing one of the wires from the switch and see what happens.

I'm presuming the wire would be positive so would need to be made safe when disconnecting it.

[NWH]

Either that or it’s wired up wrong you think you are switching it to hot and it’s wired up for winter.

[robert mitchell]

I think Nigel might be right the switch has been hit and put it into winter mode that reduces the water temperature , it’s easy dine it happens to ours now and again when switching on  the fill valve .

If it is the switch then there is also the possibility that the switch is faulty. If switching the switch doesn't do anything, then I would try removing one of the wires from the switch and see what happens.

I'm presuming the wire would be positive so would need to be made safe when disconnecting it.

I didnt bother reconnecting the summer /winter switch as it says in the handbook if it doesn't get a signal it defaults to the engine off temperature , the higher one.

[robert mitchell]

Could it be a problem with the plate heat exchanger?

[NWH]

Usually when all is working fine and the heat drops it’s the heat exchangers-exchanger,my old single exchanger unit I had did this I changed it and it was back to normal you can’t clean them out with anything they just need changing.

[robert mitchell]

NWH was right , heat exchanger was partially blocked , preventing the webasto going into full heat mode .

Managed to clean it out using a dishwasher tablet dissolved in hot water , left for an hour then flushed with garden hose ......loads of grey sludge came out of the coolant side of the exchanger .

Running spot on now , thanks a for your help .

[NWH]

Everything I post is S**t m8 don’t give me that lol told you pal when you’ve had 1 for as long as I have I can fix them in brail. 👌

[NWH]

And no problem Richard happy to help m8.

[NWH]

Got my V4 thermopure on order m8 👍