[Tom White]

A local window cleaner just called to see how my RO housing membranes unit things were connected up (his 4 year old grandson dismantled his), but mine doesn't seem to make sense.

Has anyone got a diagram or a picture I can use to see how it's done?  It'd be funny if it was connected wrongly after all these years.

[Don Kee]

Is it a normal 450gpd r.o mate?

Mine is set up so after the prefilters the inlet splits into 3 (2 t pieces) so that all the membranes have there own feed and same ingoing tds. All the wastes join up and go wherever, all the pure outlets into one hose then to the tank

Others are set up so that the second membranes inlet is the previous membranes waste water, and the second membranes waste feeds the third
(Hope that makes sense)

I prefer the first way as all the membranes get even wear
Apparently the second way cuts down waste water (which doesnt really matter unless you're on a metre, and its minimal anyway) but the second and third membranes get a hammering as they're using a higher tds (waste water) as there feed


I hope that makes sense, sorry no pics though...

[Tom White]

Is it a normal 450gpd r.o mate?

Mine is set up so after the prefilters the inlet splits into 3 (2 t pieces) so that all the membranes have there own feed and same ingoing tds. All the wastes join up and go wherever, all the pure outlets into one hose then to the tank

Others are set up so that the second membranes inlet is the previous membranes waste water, and the second membranes waste feeds the third
(Hope that makes sense)

I prefer the first way as all the membranes get even wear
Apparently the second way cuts down waste water (which doesnt really matter unless you're on a metre, and its minimal anyway) but the second and third membranes get a hammering as they're using a higher tds (waste water) as there feed


I hope that makes sense, sorry no pics though...

Thanks, it makes perfect sense.  I think I've made a big boo boo!  I think some time ago one of my membranes went 'kaput' and one was fine.  So what I think I did was re-jig it so that the water just went through one - then forgot about it - ordered another couple of membranes, and then run it like that ever since.

I'm not sure though; I'm going to have another look.

[Spruce]

and then Tosh, to add further confusion, another supplier coupled the 3 membrane r/o differently again. The first 2 membranes were coupled in parallel with the supply feed split into 2 as was the waste. The waste from the first 2 became the input for the 3rd membrane. The waste from the 3rd membrane then went to the drain. All 3 pure outlet were linked together and routed through the tiny di housing.

[Tom White]

I took the whole shebang apart today, replaced two filter housings and attached them all to a new metal plate thing and made sure the two membrane housings were correctly joined.

I did them in series, 'cos it's simpler that way.  I suspect that if they're done in parallel the water will still go through one filter more than another because water finds the easiest way to travel.

My membranes were wrongly connected though - my fault - and for about six months all the water was going through just one 150 gal membrane.  Then I purchased 2 x 100 gal membranes, and because the water was going through one, I thought that they weren't good enough, so purchased 2 x 150 gal membranes.

But the 2 x 100 gal membranes seem to produce plenty.  I've got a new 100 gal restricter on it.

It really was about time I learnt something about RO units.

Why do people use 4040's?  They seem expensive in comparison?  Are these for people who don't use static tanks and need to produce water in the van quickly?

[Spruce]

I took the whole shebang apart today, replaced two filter housings and attached them all to a new metal plate thing and made sure the two membrane housings were correctly joined.

I did them in series, 'cos it's simpler that way.  I suspect that if they're done in parallel the water will still go through one filter more than another because water finds the easiest way to travel.

My membranes were wrongly connected though - my fault - and for about six months all the water was going through just one 150 gal membrane.  Then I purchased 2 x 100 gal membranes, and because the water was going through one, I thought that they weren't good enough, so purchased 2 x 150 gal membranes.

But the 2 x 100 gal membranes seem to produce plenty.  I've got a new 100 gal restricter on it.

It really was about time I learnt something about RO units.

Why do people use 4040's?  They seem expensive in comparison?  Are these for people who don't use static tanks and need to produce water in the van quickly?

We had a 450 GPD r/o for 7 years and it was fine for supplying water for 2 vans with a little planning. Water was (and still is) processed into a 1000l IBC tank. Water collection had to be planned especially during the winter months when production is slower.

A couple of years back we introduced a third van but the r/o couldn't keep up. I often had a half day due to a water shortage. Not being able to get out due to bad weather wasn't a total loss as it meant we got a breather which allowed the r/o to catch up a little. So when the membranes of the r/o needed replacing, we opted to go down the 4040 route.

We don't have a problem with water now. Often if son in law fills up in the early afternoon (he has a 500 litre tank in his van as well) I don't know he has been for water in the evening as the r/o has already replaced the water he has drawn off.

You need to get the correct restrictor for your 150GPD membranes as it is different to the 100GPD. Doug from www.daqua.co.uk should have the correct one.



 

[Don Kee]

Just to add to spruces post Tosh, it sounds like your r.o is at best a 300gpd R.O as you only mention two filter housings?
Add one more houding mate, turn it into a 450gpd
If you're one van using around 650litres a day, a 450gpd will be plenty fine

[Tom White]

Just to add to spruces post Tosh, it sounds like your r.o is at best a 300gpd R.O as you only mention two filter housings?
Add one more houding mate, turn it into a 450gpd
If you're one van using around 650litres a day, a 450gpd will be plenty fine

I've two filter housings and a DI, so three in total.  Is this what you mean by a 300 gpd?  I only replaced two filter housings because the third was in good nick already.

@Spruce, I've already got the correct restrictor for the 150 gal membranes.  Cheers.

[Don Kee]

Just to add to spruces post Tosh, it sounds like your r.o is at best a 300gpd R.O as you only mention two filter housings?
Add one more houding mate, turn it into a 450gpd
If you're one van using around 650litres a day, a 450gpd will be plenty fine

I've two filter housings and a DI, so three in total.  Is this what you mean by a 300 gpd?  I only replaced two filter housings because the third was in good nick already.

@Spruce, I've already got the correct restrictor for the 150 gal membranes.  Cheers.

Yes mate, your 2 housing will be 150gpd each making it a 300

So because You already have 2 150gpd 'filter housings'/membranes, i would add another 150gpd membrane/housing, turning it from a 300gpd to a 450gpd
Then your D.I

3 x prefilters - 3 x 150gpdmembranes (making it a 450) - D.I

(Your D.I has no bearing to the gdp of your R.O)

[Tom White]

Cheers, Don Kee.  I might do that; it's not difficult to do; now I know about them.

[Don Kee]

No worries mate, because you've got your membranes in series i would just take 5 mins once a month and check tds of each membrane (just disconnect after the membrane, 2 min job)
If your tds goes up, chances are it'll only be one membrane not all 3, so this way you'll keep on top of it

Mine are in parrallel so if my tds goes up chances are it'll be all 3 (which i guess is a downside to the parrallel)