Problem with Static RO set up

[Greener]

Hi All, especially @Alex Gardiner @doug atkinson

Firstly sorry for the long thread Im just trying to give as much info as poss

Im in the middle of trying to set up a new static RO, I purchased the Gardiner 40-40 housing :

FRP 4040 - 4"x40" RO Membrane Housing with Brackets - RO Housings & Fittings - Water Treatment - Pure Water Systems - All Products Gardiner Pole Systems

and the Axeon HF5 4040 Membrane:

AXEON HF5 4040 40" RO Membrane - Reverse Osmosis Membranes - Water Treatment - Pure Water Systems - All Products Gardiner Pole Systems

Ive followed the fitting instructions to the T and am confident that Ive plumbed it in correctly (Pictures Attached)

Photo 1: Water inlet after Pre filters

Photo 2: Water inlet (Tap) to Pre filter then water inlet into membrane

Photo 3: waste and pure outlet

1

I have two problems, the first one being pressure, I tested my tap pressure using one of these:

Mains Water Pressure Test Gauge 11 Bar - Toolstation

And the reading I get from outside Tap is 70psi, I have ran around 20ft of garden hose from the tap then plumbed onto pressure gauge connected to the first pre filter as shown in picture No2. I expected a small drop in pressure due to the length of the hose, however the gauge shows a psi of only 40psi when I turn the water on Full.

I have also tested the flow rate coming from the hose (20ft) and the flow is I believe really good 14ltr per min?

Ive also tested the flow rate after the pre filters and this is around 12-13ltr per min.

Now on to the RO and water production, I have fitted a gate valve I purchased from Pure Freedom,This has a small hole drilled in it so it doesn't close fully as required when using on a RO.:

Brass Female / Female Gate Valves-1/2" BSP - Pipe Fittings and Valves - Fittings & Acc's

Whilst the gate valve is fully opened (to flush the membrane) I have no pressure through the Pre filters and subsequently the RO housing although I do have a very fast flow rate coming through the waste hose,as I understand it this would be correct?

As I understand it to produce pure I need to slowly close the the gate valve so roughly around half way and this will then increase the pressure within the membrane and in turn start producing pure as well as waste water?

However I need to close the waste valve fully (with only the small hole allowing waste water through) to achieve any pressure (a measly 40psi). Even with the gate closed fully the flow from the waste hose seems to still be high and the pure is IMO slow:

5mins 38sec to fill 10ltr pure

2mins 52sec to fill 10ltr waste

Tap TDS 298ppm

Pure from RO 22ppm

At first I thought the gate valve may be faulty, however I have eliminated this but opening the gate valve fully but restricting the flow by kinking the waste hose to simulate the reducing affect but the results are the same (a measly 40psi) .

mins 38sec to fill 10ltr pure

2mins 52sec to fill 10ltr waste

Tap TDS 298ppm

Pure from RO 22ppm

Any help advise would be very much appreciated as its dong my head in :thumbsup:

 

[doug atkinson]

Looking at the figures it will be the gate valve at fault. I'm not a fan of pre-drilled holes and would only use a gate valve to set the ratio. With your pressure I would expect on a setting of 50/50 a litre to take 15/20 secs

 

[Greener]

Looking at the figures it will be the gate valve at fault. I'm not a fan of pre-drilled holes and would only use a gate valve to set the ratio. With your pressure I would expect on a setting of 50/50 a litre to take 15/20 secs

Hi @doug atkinson and thanks for your prompt reply :thumbsup: (the reading I get from outside Tap is 70psi, I have ran around 20ft of garden hose from the tap then plumbed onto pressure gauge connected to the first pre filter as shown in picture No2. I expected a small drop in pressure due to the length of the hose, however the gauge shows a psi of only 40psi when I turn the water on Full) can you think of the reason I have such a drop in psi?

also At first I thought the gate valve may be faulty, however I have eliminated this but opening the gate valve fully but restricting the flow by kinking the waste hose to simulate the reducing affect but the results are the same (a measly 40psi) /emoticons/sad.png.

 

[Greener]

I'm not a fan of pre-drilled holes and would only use a gate valve to set the ratio. With your pressure I would expect on a setting of 50/50 a litre to take 15/20 secs

Hi @doug atkinson Please could you explain in a bit more detail as I don't quite understand? Many thanks

 

[Greener]

I'm not a fan of pre-drilled holes

so are the gate valves with pre drilled holes meant to be fully shut to produce a set amount of waste/pure??

 

[spruce]

so are the gate valves with pre drilled holes meant to be fully shut to produce a set amount of waste/pure??

I hadn't linked your purchasing the gate valve from Pure Freedom and it arriving with a redrilled hole in the valve. Sorry.

If the valve has a hole in it then it will allow a certain amount of water to waste, so slowly close it some more and see what happens.

One of the local cleaners has a 4040 unit supplied by PF and he fully closes his gate valve when I watched him complete a flush once.

Maybe the thing to do is to go down to your local plumbing outlet and buy a standard gate valve that hasn't a drilled hole in it and put that in. I drilled a 1mm hole in mine as I was concerned that one of the lads might mess with it and I didn't want the membrane inadvertently damaged.

 

[spruce]

Looking at the figures it will be the gate valve at fault. I'm not a fan of pre-drilled holes and would only use a gate valve to set the ratio. With your pressure I would expect on a setting of 50/50 a litre to take 15/20 secs

@Greener, Doug means that with a pure to waste ratio of 50/50 (equal amounts of waste to pure) you should produce 1 liter of pure in twenty seconds or 3 liters in a minute.

At 50psi with an HF5 membrane I'm getting approx 2 liters of waste with 2 liters of pure in a minute.