8800 Booster Pump Troubleshooting

chilake08 · May 9, 2018

So I recently had to replace a few elements on my RO/DI system and since i've messed with it the booster pump doesn't seem to be doing anything. I'm having trouble figuring it out, and was hoping for some help.

Recently I had to clean/replace some filters and the pressure gauge died on me. This is on a BRS RO/DI system with double serial connected RO membranes. When I re-assembled everything the pressure at the tap seemed to be boosted from ~40-45 up to just shy of 60psi. When engaging the booster pump the pressure didn't change. When removing the booster pump from the line the system still read almost 60. I was getting closer to 80 psi before.

I checked the power converter for the pump and its outputting the advertised 24 volts. The pump runs when plugged in and with it partially dissembled you can see it moving the diaphragm. I checked all the valves and rinsed them off, and they all seem to be in fine condition. I tried to make sure there wasn't any debris. I also messed with the pressure adjustment screw (which changed nothing).

I also made sure the flow restrictor on the waste water (550 from BRS) out of the RO membrane was working appropriately. It seems to be as best I can tell.

So I don't know if the pump is "running" but its actually broken and is moving too slow to generate the necessary pressure, or if there is something else i'm missing.

60psi isn't horrible but with 2 RO membranes i'd prefer to be in the 75-80 range.

Reefing Madness · May 10, 2018

TheEngineer · May 10, 2018

Let's do a little basic troubleshooting and see if we can narrow down the problem.

The pressure before the pump is 45psi and after the pump it is 60 psi? You see that with or without the pump plugged in? If that's true, one of your gauges is wrong. Let's ignore the gauges for a minute though and see if the pump is actually doing something... run the system with the pump on for 5 minutes and measure how much water comes out. Run the system again with the pump off for 5 minutes and measure that. There should be an appreciable difference.

TheEngineer · May 10, 2018

You could run it for a shorter time too. You can time how long it takes to produce 1 cup of water, for example.

chilake08 · May 12, 2018

Some clarification. My tap PSI used to be around 45. Recently it seems that the tap PSI has gone up to almost 60. With the pump removed from the RO/DI system, the system is running at 59 PSI. With the pump installed in the system but turned off, the PSI is 59. With the pump turned on it is 59 PSI.

There was no noticeable difference in water output with the pump engaged. I have high confidence in the pressure gauge reading as it is brand new.

The pump is not creating an increase in pressure. There is something wrong with the pump, but i'm trying to figure out if its a $20 replacement part or a $100 replacement pump.

TheEngineer · May 12, 2018

Ok, that’s much clearer. The pump has an adjustment screw on it that adjusts the bypass pressure. It is t technically for changing the pressure but that’s the effect of it. It is a small allen head screw on the top of the pump near the water connections. Tighten it a bit and the pressure should go up

theMeat · May 12, 2018

Another thing.
Carbon blocks should be rinsed before pumping through membrane. Disconnect line into membrane and run water through carbon blocks for a few minutes until it runs clear and then reconnect. If you didn’t do that you probably pushed sold carbon into pump and membrane. Which may or may not be the problem

Awesome Dennis · May 12, 2018

Is the pump actually on? Can you hear/feel it running? Do you have it connected with the kit that has the pressure sensor?

chilake08 · May 12, 2018

To answer some more questions:

The adjustment screw was the first thing I tried after looking to see if there was debris. I tried screwing it in quite a bit and back out. The pressure never changed. All the way in I think that pump is supposed to get over a 100 PSI, but then parts of the RO/DI system start leaking out the seams. Unfortunately the diaphragm for the pressure bypass is behind a piece of plastic. If there is some sort of small debris that is holding the diaphragm open that would explain why no pressure is building. I have no idea how to clean or check that.

Carbon Block rinsing. 100% agree with you. But definitely not the problem here. Upon investigating why my pump wasn't working, I learned I had it installed in the wrong spot. Its been running for years in front of the first filter stage. Fortunately I have city water that doesn't have too much crud in it. When I figure this whole thing out i'll be installing it past the filter so I know I don't have to worry about debris.

The pump does run. I can both hear and feel it moving. Additionally I turned it on without the cap on and observed it moving. Now, having said that, I can not confirm that it is running at 100%. If there is something wrong with the motor and it is moving slower than it should be, that could explain why i'm not getting pressure buildup. I am unsure if these are a type of motor that could have partial failure. The pressure sensor I have is a glycol pressure gauge that is installed on my RODI system.

I appreciate the help and ideas so far.