RO won't build pressure

[Don m]

So I'm having a problem with my RO not building pressure. I'm trying to do a rinse (beginning year rinse) and I can't get enough pressure to build to keep the low pressure cut off from kicking in. The RO is Deer Run Maple 75 so it's a smaller unit. I'm hoping I don't have a leak in the membrane which is causing this to happen. It will circulate water through but it will only flow through the concentrate side and not the permeate side (which seems backwards). Any suggestion what I might need to do to remedy this problem?

Thanks, Don

[ALSMAPLE]

Is it possible that you're supply line either has an air leak or the plug/ seal on top of the pump is drawing air? or the supply line is into the tank too far,sticking to the bottom of the tank due to the suction.

[DoubleBrookMaple]

I don't know Deer Run, but you do not say how much pressure you get, and I do not know if you have an indicator. It is possible your pump is not building pressure, or that your pressure switch has failed. If you have a pressure indicator, and you can monitor it, you can bypass the pressure switch with a jumper.
That is my first thoughts...

[DoubleBrookMaple]

Even better idea... Call Ray

[Don m]

yes I was planning on calling him. I've talked to him a few times this spring. He's a busy man and hard to get in touch with at times. We end up playing phone tag back and forth.

[bowhunter]

I would check to make sure the pressure pump isn't vapor locked. If the pump is really quiet when running you may have the pump full of air. Don't worry there won't be any permeate if the system doesn't build pressure. It sounds like you're getting some water out the concentrate side, but that could be coming backwards through the recirculation needle valve if Ray's units use recirculation? If the pump is really noisy then you may have some restriction on the suction side. Make sure the filter element is not plugged or restricted. I assume you installed a new one to start the system up. If the pump is full of water and there's no suction side restrictions such as a plugged filter then maybe the needle valve(s) is broken and is not closing properly so you can't build any pressure. You'll get it resolved once you figure out the problem. If the membrane were damaged you would be getting a lot of water out the permeate side but it would be sap.

[mapleack]

So I'm having a problem with my RO not building pressure. I'm trying to do a rinse (beginning year rinse) and I can't get enough pressure to build to keep the low pressure cut off from kicking in. The RO is Deer Run Maple 75 so it's a smaller unit. I'm hoping I don't have a leak in the membrane which is causing this to happen. It will circulate water through but it will only flow through the concentrate side and not the permeate side (which seems backwards). Any suggestion what I might need to do to remedy this problem?

Thanks, Don

I'm not familiar with Deer Runs other than seeing them, but on a rinse the flow should all be coming out the concentrate side. Like doublebrook asked, what pressure are you getting to? What is the low pressure cut out setting? Is your pre-filter clean? Obstruction in the line somewhere else? Did you change your feed tank set up or anything that would've changed inlet head pressure from last year?

[maple flats]

If you are not getting good pressure, open the membrane canister. Then lift the membrane by clamping onto one of the plastic ridges that radiate out from the center hole, do not lift on the center, Then look at the seal, It should have the open U shape open on the bottom. That way pressure forces it against the canister wall and the membrane, forming a seal. Possibly it got put in upside down, or maybe it got damaged.

[Don m]

Mapleack-

I don't get any pressure. The gauge doesn't move at all. The lower pressure cut off is set at 50 lbs. I have installed a new pre-filter. This is the second year with this RO and last year when I would do a rinse I would always have pressure. I'm sure it's something simple and not the membrane. I will double check to make sure something isn't restricting my supply flow or for a air lock. If all else fails I will give Ray a call.
Thanks for the help.

[maple flats]

Are you getting no pressure on the feed side, that is the gauge next to the pre-filter? If that is the case, make sure the feed pump is primed. That might help if you fill the wash tank, establish pressure from that, then switch to the suction line. If you lose pressure, switch back. You may have issues if there is air in the suction line. With the pump housing filled if it keep happening, my guess is that you have a leak in the suction hose.