Ro/di unit & water pressure

This question is for the RO/DI gurus out there (and you know who you are). I could not get the pressure in my RO/DI unit to go above 43 psi. Because of this low pressure, I have had to replace my membrane. carbon filters and the DI resin twice in the last six months. My solution for this low pressure was to purchase a pressure booster pump. Works great ( from BRS). My pressure went from 43psi to 92 psi. This should preserve my filters a little longer (I hope). My question is this; Is there a downside to having this much pressure (92 psi) going through my unit?

 

I'm not 100% of how at all if high pressure can adversaly effect the membranes. I know my SpectraPure model, I recall, says the target pressure going through should be around 60-70psi. I actually usually get about 50psi but fortunately my membranes have been good still since January.

I would think that the more pressure, the quality of the water would go down a bit, ie too much high volume with less quality control but I doubt it's anything significant.

I'm sure others like AZ will chime in, he's our resident RO/DI specialist.

 

Thanks MoJoe. I was getting around 55-60 psi during the winter but my psi going through my unit once it got warmer, dropped to the 43 psi. I think the pressure drop was a combination of dirty filters/membrane and the lower household pressure due to more watering in the community? I did purchase a hand-held TDS meter to double check the TDS meter on my unit (BRS) and it is showing 00.0 ppm. same as the meter on the unit. Anyway, thanks for the input.

 

No prob, I'm def no expert but when researching RO/DI systems I know I read some things concerning more TDS getting through under higher pressure, which is why they give you a target psi to shoot for optimal performance.

I also got a handheld TDS meter & it's extremely useful, I trust it's accuracy a bit more to the in-line meters, even though they're usually correct.

You could PM AZDesertRat, he's very knowledgeable & always helpful.

 

Thanks MoJoe.

 

RO membranes function better at higher pressures, not only do you get higher GPD but the quality improves significantly too.
I run my booster between 90 and 100 psi myself and get 99.35% rejection out of my membrane at over 110 GPD with 68 degree water temp and an incoming TDS between 600 and 800.

The target psi most vendors show is the pressure the membrane manufacturer tests their membranes printed performance, it is by no means its most efficient point. Membranes are the most robust part of the system with max pressure ratings of about 150 psi, the housings and fittings are the weak points so they recommend 90 psi or less in most cases.

Higher pressure is a good thing and it helps overcome colder water temps in winter months too. You are far better off to raise pressure than to try and heat the water to the recommended 77 degrees F since warmer water does not treat as well and will give you higher TDS in treated water compared to colder water.

 

Thanks AZDesertRat, I appreciate your help and expertise which is probably spot-on correct as usual.

 

Glad I could help.