[combat1]

Hi All, changed my prefilters recently and, as usual, the pressure after my booster pump has dropped to 60. Its usually 80.
Have bled the system and the pure going to the di vessel is a constant flow and dosent seem to have air in it.
This happens every time I change the filters and I never remember what I do to get it back to 80.
Bleed the system by undoing the filter vessel chambers and letting out the air, the chambers get air in them when I turn off and I bleed again until no air in system.
Any ideas
Thanks.

[Spruce]

Where is your booster pump and where is your pressure gauge fitted to your r/o Combat?

[combat1]

Booster is after the filters, which i know is different but it s always worked at 80  until filter change. Swopped the tubes yesterday to put in front of filters no difference.

[Spruce]

I agree, its confusing. If the booster and the pressure gauge were before the prefilters, then you could say that as the filters became clogged with sediment, the restricted flow would cause the booster pump pressure to rise.

The most common way of fitting the booster pump is after prefilters and before membrane/s.

[combat1]

Thanks Spruce, I have just taken all three canisters off, cleaned all the threads and o rings, silicone grease on the rubber rings and ptfe on the threads, just the same, I wonder if its the fact that I didn't flush the filters first, just changed them and started up again,

[combat1]

Update.. the booster was before the pre filters. Everyone suggested putting it after the filters, suppliers  etc.
Well it drained the canisters and burnt the pump out!
New pump fitted before the filters again and still 40 instead of 80.
Very frustrating.
I found out that by turning the waste tap a quarter turn the pressure rises back up to 80 and production is fast.
Pump sounds ok, very quiet compared to the last one. Dont think it will damage the pump?

[nathankaye]

By turning the waste valve down your creating more back pressure which is giving the higher psi reading.

The question i would be asking is why did it burn your pump out, when it was set after the prefilters and before membranes. This is the most common method, as eater pressure of a higher psi isnt required for the prefilters. However the prefilters does lower the psi of the water flow b4 it hits the membranes, hence why most put the pressure pump at this point.
Which then could be suggestive of poor tap pressure perhaps? What is your tap psi before prefilters and after prefilters? It might be worth checking that out, if youve not already done so.

[combat1]

Very clever Nathan. You are an expert.
I have a pressure guage on the inflowing tap water - around 20!.
Two possible reasons one the unit is about 25 feet from the tap and i do have a sub meter, dont know if that would reduce pressure.
I have tried putting the pump after the filters a few times, bled the air out and when the pump starts it drains the nearest filter chamber.
As you suggested i think the pump is so much stronger than the water pressure.
The old pump had done two  years.
Working well now with the tap reduced.
Pump is so quiet compared to the old one.
Thanks for your help. Seasons greetings.