Welcome to the UK Window Cleaning Forums

Starting or own a window cleaning business? We're a network of window cleaners sharing advice, tips & experience. Rounds for sale & more. Join us today!

Still Not Happy With My RO

WCF

Help Support WCF:

Tuffers

Well-known member
Messages
10,918
Location
\_( ' ; ' )_/
I've got a purefreedom setup with 20" prefilters and a 40" membrane, an HF5.

When I first got it it ran well, 008PPM out of membrane etc...

In the last few weeks it seems to have gone downhill.

I've tested the water pressure from my tap using a pressure meter and it reads 40psi. Water was coming out of the prefilters at about 38psi. It's now down to about 30psi at best, sometimes as low as 20psi. There is no hissing coming from the membrane anymore, possibly due to low water pressure?

Prefilters have been changed and flushed several times.

I changed the gate valve hoping that was knackered. That doesn't seem to be the case.

Water is about 3 parts waste to 1 part water. If I close the valve to try and get more pressure the PPM coming out of the RO goes up to 050PPM, if I open the valve the PPM comes down to around 016/017. If the valve is fully open PPM is about 030.

I have the sediment filter in the first canister and the carbon filter in the second canister.

I have a solenoid auto shut off device fitted just before the prefilters. Could this have become partly closed somehow?

My main query is why is the pressure so low coming out of the prefilters?

What is going on here? Can you help @spruce or @doug atkinson please.

 
I'm at a lost @Tuffers. Can you check to see how many liters per minute of water comes out of your tap or the pipe just before it enters the r/o.

I'm also at a lost to understand your r/o tds readings as they don't make sense to me.

When you flush your membrane the water pressure will drop on the gauge as there will be little restriction in the system. As you close the gate valve you should get an increase of pressure on the membrane which will produce more filtered water.

What I can't understand is why your best rejection rate is at 3 waste to 1 pure. It should be better at a reduced ratio.

Mine is best at about 1 waste to 1 pure. It takes time for the r/o to settle down and produce good results.

Maybe @doug atkinson has an idea of what the problem could be.

Sorry

 
Take the pre filters out and test again with empty canisters, this will rule out if you have bad pre filters.

I don't know your particular system, but generally the pre filters canisters have direction arrows (in and out) check they are the right way round.

Sent using the Window Cleaning Forums mobile app

 
I've had the same problems all week, my have produced 300L of pure in 9 hours!! Gonna check the direction of the filter but I doubt it's that as it happened out the blue last week. I'm going to attach a pump to get water going in to 100psi tonight and see if that flushes the problem out... I'll let you know. My PPM is ok, so probably a different issue but thought I'd assure you we're all having stinkers [emoji85][emoji23]

Sent using the Window Cleaning Forums mobile app

 
Last edited by a moderator:
Take the pre filters out and test again with empty canisters, this will rule out if you have bad pre filters.I don't know your particular system, but generally the pre filters canisters have direction arrows (in and out) check they are the right way round.

Sent using the Window Cleaning Forums mobile app
My prefilter canisters are fixed to the side of the system so I doubt they're the wrong way round but will check tonight,

I've been on the phone to PF and they have said to put original gate valve back on and flush for an hour. I'll give it a go but I'm not confident it will change things because this problem was happing before I changed the prefilters and I changed them thinking they were contributing to the problem. I've also pushed the red buttons down on the top of the canisters just in case there was an air lock.

 
They also asked for a reading of litres per minute going into the filters and after RO plus a waste reading because 3:1 waste is going to cost me a fortune on my water bill.

 
Have you changed your filters in time? Maybe buy new membrane and filters and start again.

 
Too me it sounds like something has clogged up the membrane. I know a couple of window cleaners in Wales and their water is awful and clogs up the membrane.

Or it could be the set up.

I travelled all the way from Scotland to Bristol as a customer had a problem with his R/O and it was fine when we tested it here. I found out what the problem was and resolved it, maybe ask Pure Freedom to do that.

I think the membrane is an issue but you would have to take it out for it to be inspected.

 
Maybe sent the wrong pr-filters?I would Check the pre-filters are 5 micron and not 0.5 micron etc

 
Too me it sounds like something has clogged up the membrane. I know a couple of window cleaners in Wales and their water is awful and clogs up the membrane.
Or it could be the set up.

I travelled all the way from Scotland to Bristol as a customer had a problem with his R/O and it was fine when we tested it here. I found out what the problem was and resolved it, maybe ask Pure Freedom to do that.

I think the membrane is an issue but you would have to take it out for it to be inspected.
Funny you say that Doug. I'm with Welsh Water. I took a photo of the last sediment filter I changed. How does this look?

image.jpg

 
If your running 3:1 you'll be pushing 6000 litres a week through your filters, how often do you change them?

 
If your running 3:1 you'll be pushing 6000 litres a week through your filters, how often do you change them?
Changed twice since September :oops:. You think membrane is knackered? But why is pressure low before it?

 
How many litres is recommended before changing filters? I know mine

mine is 10,000 and change filters every month.

 
@Tuffers take the thing to purefreedom and let them figure it out something tha new shoukldnt be messing uop
I have phoned them and they have asked for some figures regarding waste and pure per minute. I'll do the test probably later in the week. I live miles from them plus it's a 1000 litre IBC system. I just can't understand why the pressure is low before the RO and after the prefilters. I've also attached the input pipe to another tap to rule out low pressure from the garage tap I use, but it's still the same. When I put a water pressure meter on either tap it reads 3 bar or around 40 psi, when I take a reading off the unit it reads 2 bar or around 30 psi. I think I might have to get a new membrane the way it's going.

 
So - your prefilters are dragging your pressure down 10psi? That in itself is not 'that' unusual but consider now that you are only pushing 30psi through your membrane, your waste to pure will be poor at that. Your sediment filter looks normal to me and if you are using the fibredyne carbon from gardiners you have - essentially- two pre filters at 5 micron (I believe). Something must have changed with the pre filters (brand/quality?) to make such a difference to the pressure which is causing a knock on effect to the pressure into your RO and subsequently your product TDS. Do you have anyone near to you that can plug in a booster to see if your membrane performs again? Other than that try operating using pure instead of your tap water, that should clean your membrane out. I'd be surprised if your membrane has gone unless you've missed carbon filter changes.

Sent using the Window Cleaning Forums mobile app

 
Back
Top