Waste/pure ratio

[TimB]

Reading your first post you stated the pre-filters were new so did you not replace them.

So I put in the black webbed filter (carbon?) 4 months ago, and the white one (sediment?) 6 weeks ago. I thought they might be the issue so I replaced both with my last new filters at the weekend. The problem persists.

Wondered if leaving the carbon one too long has caused it.

 

[doug atkinson]

Did you get those from us or elsewhere.

 

[TimB]

Did you get those from us or elsewhere.

They were part of a big box that I was given as part of the sale. Found the box with what I think is a label for the carbon filter and a single white filter. So here ya go.

 

[doug atkinson]

Okay filters are fine. What is your pressure gauge reading.

 

[TimB]

Okay filters are fine. What is your pressure gauge reading.

100 psi reading on the guage you can see. Just before it enters the membrane.

 

[scottish cleaning service]

I think you need to flush the carbon filter before you fit it or all the dust goes through the membrane.

 

[ched999uk]

@doug atkinson is the man but just in case. How do you set your waste flow? If it's a gate valve with a hole drilled the holes can wear and let more waste out, if it's just a specific position of the valve then again it could have worn causing more waste to flow.

 

[TimB]

I think you need to flush the carbon filter before you fit it or all the dust goes through the membrane.

Uh oh. Too late!

 

[TimB]

@doug atkinson is the man but just in case. How do you set your waste flow? If it's a gate valve with a hole drilled the holes can wear and let more waste out, if it's just a specific position of the valve then again it could have worn causing more waste to flow.

I don't know as I've never disassembled it since purchase. If the filters are fine as Doug says then the red valve is definitely the likely culprit. To be honest it is looser than it used to be when I turn it. Maybe its wearing out, I just find it a bit confusing as it still works- increases the pressure to 100psi when I close it.

 

[doug atkinson]

Couple of things to check.

Make sure your water tap is fully open
Press the red valves on the filter housings as there may be an air bubble. If water comes through then fine.

Slightly reduce your waste to say 2 litres a minute to see if that increases pure output

 

[TimB]

Couple of things to check.

Make sure your water tap is fully open
Press the red valves on the filter housings as there may be an air bubble. If water comes through then fine.

Slightly reduce your waste to say 2 litres a minute to see if that increases pure output

OK so red buttons produced tiny amount of air before putting out water- no difference to output. I can't increase waste to 2 litres. My pump gets really loud and psi goes to 140 immediately.

I cannot increase pressure before the membrane any more than i have. Maybe others were built differently, but a few have said decrease waste by turning the valve. Seriously think it would explode based on the guage and what it sounds like. Now checking waste valve.

 

[TimB]

Thanks for the help everyone but it's a lost cause I think. Appreciate the responses. After taking everything apart and putting it together, it's no better. Speed of output is in the screen grab of a vid below as i couldnt post the video. Tds is 1 after resin after 2 months and 10,000+ litres on the resin and 4 months on the membrane. So I'm going to just have to put up with it being 70/30 ratio or worse. If it wrecks the membrane then so be it, I'll buy a new one.

Doug, if you can recommend how often the carbon filter should be changed, I'd appreciate it. Thanks.

 

[spruce]

Thanks for the help everyone but it's a lost cause I think. Appreciate the responses. After taking everything apart and putting it together, it's no better. Speed of output is in the screen grab of a vid below as i couldnt post the video. Tds is 1 after resin after 2 months and 10,000+ litres on the resin and 4 months on the membrane. So I'm going to just have to put up with it being 70/30 ratio or worse. If it wrecks the membrane then so be it, I'll buy a new one.

Doug, if you can recommend how often the carbon filter should be changed, I'd appreciate it. Thanks.

I know you have asked Doug, but here's my take.

Different manufacturers quote different usage figures. For example, Fiberdyne 10" filters have a service life of 37800 litres. Some have a service life of 6000 litres, others quote a service life of 10,000 litres and some others, 12000 litres.

The service life of a carbon block filter includes both pure and waste. So if you were using 1,500 litres of pure a week and your waste to pure ratio was 2 waste to 1 pure then your water usage is 3 litres, not 1.

The only way to know when to change your prefilters is to put your r/o on a water meter. I change my Fiberdyne 20" c/b every 77,000 litres, or approx once every 3 months.

The service life of a carbon block filter will depend on how much chlorine is in your water at any given time. If the chlorine in my tap water was half of what the spec is based on, then in theory my c/b filter should last twice as long. I don't know how much chlorine is in my water at any given time, but I have found that using the manufacturer's spec my 4040 membrane is still working to a 97% rejection rate after 10 years.

The first r/o I purchased was from a windie in our area. The r/o was a year old and he had never changed the prefilters. The membranes were shot. So I know I can't leave my prefilters in my r/o for a year without damage to the membrane. Of course, that's a snapshot of my experience 16 years ago. It may not be relevant at all now, as the water board could have improved their dosing methods.

 

[doug atkinson]

Take out the filters for couple of minutes and see if that improves the flow.

Next run without the booster pump and set to around 55% waste to 45 % pure and see what results you get.

 

[TimB]

Take out the filters for couple of minutes and see if that improves the flow.

Next run without the booster pump and set to around 55% waste to 45 % pure and see what results you get.

The pressure is absolutely fine after the filters, as I checked that before. I can remove the filters but if they aren't affecting pressure in the pipes after them how will removing them do anything?

I ran without pump, and to get a near 50/50 ration I have to turn waste outlet valve to almost closed and a very small stream comes out of both. Reads 60 on pure doing this at closer to 2 mins production.

I have now replaced the outlet 'wheel' with a lever valve but the issue is still there. The only logical thing left, surely, is the membrane or the membrane housing. Is it possible for a 4021 membrane to slow after 5 months like that? The housing is an old style, no idea if that is a problem either.

 

[ks789]

The pressure is absolutely fine after the filters, as I checked that before. I can remove the filters but if they aren't affecting pressure in the pipes after them how will removing them do anything?

I ran without pump, and to get a near 50/50 ration I have to turn waste outlet valve to almost closed and a very small stream comes out of both. Reads 60 on pure doing this at closer to 2 mins production.

I have now replaced the outlet 'wheel' with a lever valve but the issue is still there. The only logical thing left, surely, is the membrane or the membrane housing. Is it possible for a 4021 membrane to slow after 5 months like that? The housing is an old style, no idea if that is a problem either.

Hi Tim, kev here.
Yes seems strange. I used to get roughly 2 litres a minute ( if I recall correctly) but needed the booster for that, and the waste was roughly 3 litres a minute or say 60/40. Membrane was still going well after 4 1/2 years of not heavy use. I never bothered with water softener to help preserve the membrane but had heard that many in our hard water areas do. Either way It seems something amiss if performance down badly after 4 months.

 

[TimB]

Hi Tim, kev here.
Yes seems strange. I used to get roughly 2 litres a minute ( if I recall correctly) but needed the booster for that, and the waste was roughly 3 litres a minute or say 60/40. Membrane was still going well after 4 1/2 years of not heavy use. I never bothered with water softener to help preserve the membrane but had heard that many in our hard water areas do. Either way It seems something amiss if performance down badly after 4 months.

Hi Kev, its been great since april and the new membrane. This all happened over last month.

I will be taking it apart soon including the membrane housing to have a look at it and see if anything obvious is blocking things. Problem is I need to run the system 4 hours a day just to keep my work going so don't get to tinker much until weekends!

I'm very confused by it, but don't want to shell out another few hundred quid until I've exhausted all options and given it a few weeks.

 

[spruce]

I thought it was the higher pressure your booster pump is putting on the membrane, but the Axeon specs give a maximum pressure rating as 600psi.

https://go.axeonwater.com/hubfs/AXEON%20Specification%20Sheets/MKTF%20-%20134%20-%20C_HF4%20Series%20Spec%20Sheet.pdf

I would try to reduce your waste ratio and not worry too much about pressure. The Champ housing has a maximum design pressure of 225 psi, so you need to stay within that figure.

https://www.lenntech.com/Data-sheets/Axeon-Membrane-Housings-L.pdf

@doug atkinson

 

[doug atkinson]

The only thing that will reduce the flow in your membrane if it’s blocked due to dirty water coming in. This is normally caused by dirty mains water.

You can normally unblock it if you flush your membrane for a good hour or so.
If that fails then the membrane may be blocked.

A tell tale sign is when you open the membrane housing and dirty water comes out.

 

[TimB]

I thought it was the higher pressure your booster pump is putting on the membrane, but the Axeon specs give a maximum pressure rating as 600psi.

https://go.axeonwater.com/hubfs/AXEON%20Specification%20Sheets/MKTF%20-%20134%20-%20C_HF4%20Series%20Spec%20Sheet.pdf

I would try to reduce your waste ratio and not worry too much about pressure. The Champ housing has a maximum design pressure of 225 psi, so you need to stay within that figure.

https://www.lenntech.com/Data-sheets/Axeon-Membrane-Housings-L.pdf

@doug atkinson

This is helpful info Spruce, thanks. I had no idea it could run at that pressure.

 

[TimB]

The only thing that will reduce the flow in your membrane if it’s blocked due to dirty water coming in. This is normally caused by dirty mains water.

You can normally unblock it if you flush your membrane for a good hour or so.
If that fails then the membrane may be blocked.

A tell tale sign is when you open the membrane housing and dirty water comes out.

Thanks Doug. I will be opening the membrane housing this weekend(if I can, thing is not easy!), and if it's not dirty I'll flush it for an hour.

If it is mains water, that's the problem...we'll I rent, so not much I can do. But I suppose flushing for longer periods might help?