[mgba_78]

Just need a little advice on my RO and how to tweak.

So got a call from a customer and said windows dried spotty, so checked TDS and it was reading 70ppm.
Now i only changed the resin about 2 months a go as it was shot and again not giving 000ppm reaading

So when took pipe of DI and water was coming out of RO at 70ppm, proving resin is shot, but should i be getting lower reading from my RO before it goes to the resin?

Im running a 4040 RO and a 25ltr DI vessel no booster pump.
If i want to lower the TDS which comes from the RO do i adjust the waste valve to produce more waste?  Also what sort of  TDS figure from the RO should i be aiming for before it goes to DI

Ta

[timglaze]

Try flushing the system. You can do this by adjusting the nozzle so that all the water comes out of the waste pipe. Do it for about 10-15 mins. Also keep the pre filters fresh, I didn't change mine for a while and I was getting 130+ out of my RO. I get about 35 now and 19-20 with a booster pump.

[Spruce]

Lots of info regarding 4040's on the search button.

What's your rejection rate?
What's input tds?
When did you last replace prefilters?
How old is the membrane?
What is you water pressure from your supply tap?

[Matt.]

What tds out of tap before RO and by the sounds of that it's the water pressure

I connect my merlin up to lots of places and roughly get between 14-20 tds if I connect up at my home with tap tds of 150ish I get 70ish after merlin
 I know this is due to pressure being to low so I persist with using customers taps 

[mgba_78]

Lots of info regarding 4040's on the search button.

What's your rejection rate?     dunno
What's input tds?     190ppm
When did you last replace prefilters?    2 months back when I did resin
How old is the membrane?     2 years
What is you water pressure from your supply tap?      dunno

[timglaze]

Did you not get pressure gauges with your pre filters? They usually come with the 4040 setup

[SB Cleaning]

70 sounds high after RO mine is 12 ish with a tap tds of 240....

I would guess your RO is shot.

[Walter Mitty]

Lots of info regarding 4040's on the search button.

What's your rejection rate?     dunno
What's input tds?     190ppm
When did you last replace prefilters?    2 months back when I did resin
How old is the membrane?     2 years
What is you water pressure from your supply tap?      dunno

Similar TDS to me.  I have a 4040 that runs at 35-40 PSI (no pump).  Rejection is about 50-60% (manual viewing estimate).  I change the prefilters 4 monthly  - though have left it for 6 months (these are 20".  10" will need more frequent changes.  It's been running for about 5 years now and still produces at around 008 (I polish with resin).  I'm guessing that it works OK because I turn the waste full on for about 15 minutes once a week (sometimes twice).
N.B.  I get a very high TDS reading from it on start up so run the first few litres as waste.  It settles down after a few minutes though.
Mine is the HF5 variety due to the low water pressure.  If you are on low pressure and using an HF4, maybe that is the issue (or maybe not).  Or perhaps you need to turn waste full on sometimes.

[SeanK]

I would say you need a new membrane as you should be getting your water down to around the 2ppm with that tap input.
The first thing you will need to do is find out how good your tap pressure is, this will let you know if your need a booster pump.
To be honest mate I would also run the RO and the DI separately, it a far better way of keeping an eye on the performance of
your RO and stops any accidental  contamination of your resin when flushing and so on which is a must do with a 4040.
Put your water through the DI as needed, you will hear some silly excuses on here for not doing this but from the time I have
spent on forums like this its seems that the people who get the least life and the most hassle from their RO's are the guys who
purify in one go.
When you change your membrane run all the water to waste for an hour or so just to break the membrane in then slowly
adjust the pure to waste ratio until you get the pure tds to as low as it will go, but don't go over the 50/50 mark pure to waste
and never run all the water to pure as this will damage the membrane.
When you have finished open up the tap ready for the next session so that you never start with the full pressure hitting the
membrane ( that's how you get RO shock which is hard on membranes) always run a few minutes with the water running
fully to waste and slowly build up the pressure.
You will get to know the pure to waste ratio just by watching the flow coming from the waste outlet.
4040 membranes when working right remove 98% of dissolved solids so you should be getting between 2 and 4ppm
and at least five years of use from it.

[Spruce]

Lots of info regarding 4040's on the search button.

What's your rejection rate?     dunno
What's input tds?     190ppm
When did you last replace prefilters?    2 months back when I did resin
How old is the membrane?     2 years
What is you water pressure from your supply tap?      dunno

Input to membrane (tap TDS) = 190

Output from r/o  = 70

Your r/o membrane is running at 63% efficiency. It should work at around 97 to 99% efficiency. My thoughts are that a booster pump won't help much as your membrane needs replacing.

How often to you replace prefilters?

 

I would say you need a new membrane as you should be getting your water down to around the 2ppm with that tap input.
The first thing you will need to do is find out how good your tap pressure is, this will let you know if your need a booster pump.
To be honest mate I would also run the RO and the DI separately, it a far better way of keeping an eye on the performance of
your RO and stops any accidental  contamination of your resin when flushing and so on which is a must do with a 4040.
Put your water through the DI as needed, you will hear some silly excuses on here for not doing this but from the time I have
spent on forums like this its seems that the people who get the least life and the most hassle from their RO's are the guys who
purify in one go.
When you change your membrane run all the water to waste for an hour or so just to break the membrane in then slowly
adjust the pure to waste ratio until you get the pure tds to as low as it will go, but don't go over the 50/50 mark pure to waste
and never run all the water to pure as this will damage the membrane.
When you have finished open up the tap ready for the next session so that you never start with the full pressure hitting the
membrane ( that's how you get RO shock which is hard on membranes) always run a few minutes with the water running
fully to waste and slowly build up the pressure.
You will get to know the pure to waste ratio just by watching the flow coming from the waste outlet.
4040 membranes when working right remove 98% of dissolved solids so you should be getting between 2 and 4ppm
and at least five years of use from it.

Agree with SeanK.  At the input tds you could be looking at a ratio of around 60% waste to 40% pure with reasonable water pressure. You will be able to tweak it using your tds meter and taking samples of water after the r/o but before di.

I use an inline tds meter. The input is after the r/o and the output is after di.

We also use 20" prefilters as they last longer, HF5 membrane (our water pressure is 50 psi), no booster and the membrane is 3 years old. Its still producing the same output tds of 2 as it did when we first bought it 3 years ago.

Here is a calculator

http://www.apswater.com/calcs.asp?Feed_conductivity=190&Product_conductivity=70

[Walter Mitty]

To be honest mate I would also run the RO and the DI separately, it a far better way of keeping an eye on the performance of
your RO and stops any accidental  contamination of your resin when flushing and so on which is a must do with a 4040.
Put your water through the DI as needed, you will hear some silly excuses on here for not doing this but from the time I have
spent on forums like this its seems that the people who get the least life and the most hassle from their RO's are the guys who
purify in one go.

I purify "in one go" but there are ways of doing it that allow the RO TDS to be monitored - especially if someone doesn't want a DI vessel in the van.  I have John Guest tubing.  I fitted a couple of those plastic taps which allow me to temporarily stop the flow to the DI and into a cup, or similar, where I can test the RO TDS.  It also allows me to run the first few litres of high TDS (after start up) into a container.
I suppose it depends what the guy wants really.  I suppose that it might suit him to have a resin vessel in the van - especially if he sometimes needs to top up from a tap while out on his round.

[mgba_78]

Its deffo the membrane! 

After RO before DI best with tweaking the waste valve is 89ppm now!!!  LOL

Ill order a new one!  I think this has been in for over 2 years so not too bad a life i suppose.
Admittedly i am a bit lapse with changing the pre filters,  maybe 3 times a year at most!
Cheers guys I think i knew the membrane was shot but didnt want to accept it lol

[slap bash]

A membrane should reduce your input rate to 10 % or less at least to be in good order. |This is clearly not happening so you memebrane is shot