[Paul Coleman]

My pure water production has slowed down a lot recently and I don't know what the problem is.
I have a 300 gpd pumped RO.  It is currently producing about 10 - 11 litres per hour of pure water (about 250 litres per day).  Previously, it was producing about 480 litres per day.  I am unsure at how sudden a change this has been as I was away for a while and I haven't needed much water recently.  The system is a few miles from home so I don't check it regularly.
Water pressure is fairly lowish at the site but it appears to be flowing from the tap as much as ever and does not appear to have changed.
There is no accompanying sharp increase in TDS (009 out of RO) so the membranes don't appear to be the culprit (they are only a year old anyway).  The sediment and carbon pre-filters are not due to be changed until the end of August.
I can see that the pure water is coming out more slowly.  The waste has also slowed down so it's not a case of the proportions having been altered.

Setup is sediment, carbon + 3 membrane housings and the system is pumped.  There is no backflush on it.  Nothing has been altered recently. 
Any knowlegeable views on this please?

[brightnclean]

Hi Shiner.

I am suspecting your pump is dicky.

Try running the RO without the pump if you can and see what happens.  Also no flush is a bad thing mate    If you are in a high limescale area the membranes could well be done in already. Its pretty easy to retro fit a flush. Your RO has to have a flow restrictor on it. Usually your waste pipe runs out from that. RO man or anywhere that does RO bits could set you up. All you need to do is put a push fit T just before the flow restictor with an on/off tap on a piece of pipe leading from the T piece.  You can then open the tap and merrily flush away    It isnt a back flush but the best thing you can do with the multi 100 GPD membrane systems.

[busted]

hi shiner
              i have been having the same problems as you , my booster pump packed up on me so i sewnt for a new one and i now have it all fit together but im still not making as much water as i was before with the other pump. i did phone the people i got the pump from they said just keep on flushing the ro it may help if not to phone them back

[Paul Coleman]

Hi Shiner.

I am suspecting your pump is dicky.

Try running the RO without the pump if you can and see what happens.  Also no flush is a bad thing mate    If you are in a high limescale area the membranes could well be done in already. Its pretty easy to retro fit a flush. Your RO has to have a flow restrictor on it. Usually your waste pipe runs out from that. RO man or anywhere that does RO bits could set you up. All you need to do is put a push fit T just before the flow restictor with an on/off tap on a piece of pipe leading from the T piece.  You can then open the tap and merrily flush away    It isnt a back flush but the best thing you can do with the multi 100 GPD membrane systems.

I already know what happens if I run the RO without the pump.  Absolutely nothing !!  I had a pump pack up on me over a year ago and there is no water production at all without one.  However, the old pump was still inline.  Are you suggesting that I remove the pump and join up the pump inlet with the pump outlet?  I suppose I could do that if I got a wide enough connector.  I suspect it wouldn't help though as the water pressure is on the low side.  This pump sounds like it is working just fine but I wouldn't know what to look for.

I suspect that what you say about limescale is more likely to be the problem.  However, the water I use at home and the water that supplies my RO are from different sources and water companies as my RO is a few miles from home.
The TDS going into the RO is around 200 - fairly good for a hard water area.  Would a lot of limescale be reflected in a higher TDS?  What is the best way to combat high limescale?  Is it via a backflush?  Or is there an extra pre-filter that can be added to the system.  I don't want to be changing those membranes every year if I can get away with it.  I remember that when I first used the RO it was giving me about 600 - 650 litres a day (20 months ago).  Then it settled down into about 450 - 480 litres a day.  I changed the membranes nearly a year ago as I wrecked them by not changing the pre-filters soon enough (I misunderstood what I was told).  Now it's taken a further dip to about 250 litres per day.  I do remember someone scraping away something that may have been limescale from where the tubes meet the membrane housings.
If backflush cures this, I'm wondering if I need to buy a new RO that can take a proper backflush.  I'm reluctant to go the 4040 route as that would be overkill but I would rather have too much production than not enough.  250 litres a day will not meet my needs but 480 did (just).  You see, I not only want to solve the current problewm but I want to prevent it re-occurring in another year.

[brightnclean]

I honestly dont think you can trully back flush this type of system but a manual flush system has to help a lot. All it does is stop the back pressure caused bt the flow restrictor and allows the water to flow freely through the system at a much higher flow rate. It IS easy to fit one if you havent got one. I did it for a mate a few weeks ago..

The only thing that will take the limescale down before the RO is a water softening unit. I had one on my 40 inch RO and to me eternal shame got fed up regenerating the resin with the salt solution every fill and B8ggered the membrane up. 200 is not a very high reading.. Mine is around 420   Mind you if the calcium content of that 200 is high then yes it could well be the membranes that are gone again. From what you have said about your water pressure I suspect they are 

[Paul Coleman]

I honestly dont think you can trully back flush this type of system but a manual flush system has to help a lot. All it does is stop the back pressure caused bt the flow restrictor and allows the water to flow freely through the system at a much higher flow rate. It IS easy to fit one if you havent got one. I did it for a mate a few weeks ago..

The only thing that will take the limescale down before the RO is a water softening unit. I had one on my 40 inch RO and to me eternal shame got fed up regenerating the resin with the salt solution every fill and B8ggered the membrane up. 200 is not a very high reading.. Mine is around 420   Mind you if the calcium content of that 200 is high then yes it could well be the membranes that are gone again. From what you have said about your water pressure I suspect they are 

That would be a pity if the membranes have gone again.  I do have doubts though as the last time I wrecked the membranes, the slower production was accompanied by a sharp rise in TDS - which hasn't happened this time.
It may be that I need to either add a softening unit or just rip the whole lot out and start again.
It sounds like I could fit a manual flushing unit quite easily and would have no problem doing that.  However, if it only partly rectifies the problem, I could be revisiting this scenario again eventually.  If necessary, I would rather spend extra and sort it out properly.
Thanks for the feedback.

[Ian Lancaster]

Paul,

I've got an RO-man 300gpd that I bought over two years ago.  My input is anything from 230 to 320, but output is 4-7.  I religously change the prefilters when they're due, and I flush every time I start up, for at least twenty minutes.

I can make about 1200 to 1400 lts per 24hrs.

I had to replace the pump a few months ago, the one that came with the system was cr*p, noisy and unreliable.  RO-man sold me a "big" pump which gives a steady 75psi regardless of input pressure.

I think the trick is to always flush - the membranes must get clogged up so a good bath every day does them good.

I suppose I'll have to buy new membranes sometime, but at the moment they seem to be fine, and I'm running three vans off the one system!!!

Cheers,

Ian

[pjulk]

Hi Paul

I have the same filters as you.
My pump packed up several months ago and i just connected it back up without the pump and my water pressure was only 5 bars lower so now use it without the pump.

But last month my TDS out of my R/O's shot up rather quick and the water production did also dip a bit but not a great deal.
I had to change the membrane's and now is all fine again.
Not sure how long they are supposed to last but mine lasted over 2 years.

[Paul Coleman]

Paul,

I've got an RO-man 300gpd that I bought over two years ago.  My input is anything from 230 to 320, but output is 4-7.  I religously change the prefilters when they're due, and I flush every time I start up, for at least twenty minutes.

I can make about 1200 to 1400 lts per 24hrs.

I had to replace the pump a few months ago, the one that came with the system was cr*p, noisy and unreliable.  RO-man sold me a "big" pump which gives a steady 75psi regardless of input pressure.

I think the trick is to always flush - the membranes must get clogged up so a good bath every day does them good.

I suppose I'll have to buy new membranes sometime, but at the moment they seem to be fine, and I'm running three vans off the one system!!!

Cheers,

Ian

It sounds like the flushing is the key to this and possibly using water softener.  Apart from a year ago when I blundered, I have changed pre-filters 6 monthly as advised (they're 20 inch ones).  I was told that a flushing unit was unnecessary by my supplier.  I believe the pump I have is a Flojet.  Not sure about the PSI but I think it's 80.  The membranes have been in just under a year.  They were changed at the end of August last year at the same time as the carbon and sediment pre filters.  I changed the pre filters again at the end of February this year as per 6 monthly schedule.
I need to have a chat with my supplier I think to try to get this sorted out.  I can get away with low production this week as I have a nearly full van mount and will have a full IBC by the time I need it next.  I'm not woirking Thursday and Friday and I have about 150 litres in containers too so no problem there.  At least I have a weeks grace to get this sorted.
Thanks for your input Ian.

[Paul Coleman]

Hi Paul

I have the same filters as you.
My pump packed up several months ago and i just connected it back up without the pump and my water pressure was only 5 bars lower so now use it without the pump.

But last month my TDS out of my R/O's shot up rather quick and the water production did also dip a bit but not a great deal.
I had to change the membrane's and now is all fine again.
Not sure how long they are supposed to last but mine lasted over 2 years.

My membranes have been in just under a year Paul so it will be disappointing if they do need replacing as seems likely.
Tell me, do you flush regularly like Ian mentioned?
Thank you for posting.

[Kinver_Clean]

The best £20 or so we spent was an automatic flush from RO Man. It goes in the pipe instead of the flush tap and auto flushes for 1/2 min or so on switch on and then 18 secs every 20 mins or so. I pump from a header tank and there is a level switch in the pure tank to start and stop the pump. When we fill the van tank the system starts on its own. We check the TDS weekly and change the resin every couple of months otherwise we don't touch it. Our membrane has been on for 2 1/2 years now.
The pump problems may be caused by muck in the pump head or the flap valves wearing. Shurflo pumps have had problems with some of their later pump heads wearing badly. If it is making a rattlelly noise this is probably the cause. Check that the screws holding the head on the pump are tight. If you feel adventurous take the pump off the unit and take the head off and clean it. This must be done in clean conditions with a large sheet under the pump as there are some spring loaded valves that can drop out when the head is taken off. Best is to loosen the screws and then hold the pump head up and lift the top off vertically and carefully. It is amazing what gets in there even after filters.

[pjulk]

Tell me, do you flush regularly like Ian mentioned?
Thank you for posting.

Paul i flush for about 15 minutes once a week


Paul