Having issues with RODI booster pump

[turbo2oh]

I recently installed the Aquatec CDP-8800 booster pump along with my BRS 5-stage 75 GPD RODI unit. I’m running into some confusion around how the pressure switch is supposed to work.

At first, I had the pressure switch installed after the DI resin canister. Based on some research, I moved it to just before the DI stage, but when I close the float valve on my output container, the booster pump keeps running and doesn’t shut off.

Am I missing something in how this is supposed to work? Is the pressure switch supposed to shut off the pump when the float valve is closed and backpressure builds up? Also, should the booster pump be running even when no source water is flowing, or is it common practice to only power it when you’re actively making water?


Any guidance on wiring, switch placement? Trying to make sure I don’t damage the pump or waste water.

 

[mann1139]

You want that shutoff as close to the RO output as possible.

I usually put a manual valve upstream of the DI so I don't have to rely on the float switch.

I also unplug my pump when I'm not actively producing water to prevent wear and tear.

 

[EricR]

I have Aquatec CDP-8800 booster pump also, on BRS 6 stage RODI unit.
I have my pressure switch after DI, right before the float in my Brute container.
Mine works perfectly the couple of times I've forgotten I was making RODI and the couple of times I've purposely tested.
It does shut off the pump.

I've never tried to run the pump with source water OFF so not sure what's supposed to happen in that case.

You said your unit keeps running:
How high does your pressure get (when float closed and pump still running)?

 

[edd59]

pressure switch is triggered by your auto shut off valve, if your unit is not equiped with one or its not working you will keep dumping water to waste.

 

[turbo2oh]

pressure switch is triggered by your auto shut off valve, if your unit is not equiped with one or its not working you will keep dumping water to waste.

Where should it be in relation to the ASOV? I moved The pressure switch to be back after the DI canister. You can kind of see the ASOV and pressure switch both in this photo

 

[EricR]

I could be just mis-remembering but I feel like my setup works like this:
- Pressure switch is closest to float and shuts off booster pump
- ASOV is earlier in chain and cuts off source water

I feel like mine work independently but I need both to handle both needs (pump off AND no more source water flowing).

I start everything manually (pump and open source water valve) when I make water so mine are just there for end of cycle if I'm not paying attention.

 

[turbo2oh]

You said your unit keeps running:
How high does your pressure get (when float closed and pump still running)?

The pressure reading on the RODI gauge never changes (80). But if I hold the float closed the DI canister starts leaking so it’s definitely building up pressure probably post-gauge. Mentioned above but also moved the pressure switch for the pump to be back after the DI right before the brute

 

[EricR]

Right,,, that was probably a stupid question anyway.
The pressure switch should shut off the pump when the the final output pressure reaches something like 40 PSI,,, but those pressure switches are usually adjustable also.

Sounds like it's not working but that's all I got.
Hopefully others can chime in with better diagnosis ideas.

 

[turbo2oh]

Yeah I actually talked to BRS support. They say the pressure switch is adjustable. There’s a super tiny adjustment screw? I might have to buy a smaller Allen wrench assuming I’m looking in the right spot.

 

[EricR]

Yes -- super tiny Allen wrench. Not sure the size as I never adjusted mine. (It just worked fine at the default setting so I never touched it).

If you're building up so much pressure that your DI is "leaking" (if I read that right), seems like it might not just be the adjustment,,, more like the switch may be faulty,,, but good luck.

 

[edd59]

Yes -- super tiny Allen wrench. Not sure the size as I never adjusted mine. (It just worked fine at the default setting so I never touched it).

If you're building up so much pressure that your DI is "leaking" (if I read that right), seems like it might not just be the adjustment,,, more like the switch may be faulty,,, but good luck.

system pressure adjustment is on the booster pump. switch is a different adjustment.

 

[EricR]

system pressure adjustment is on the booster pump. switch is a different adjustment.

Correct -- if he wants to set his pressure switch to shutoff the pump at lower pressure (at the switch), that's what I think he's trying to adjust to see if it helps.