Water pump issues? 2021 Micro Minnie 2108DS

[dougs]

Just back from a 4-night camping trip with a question about my 2108DS water pump. We were plugged in to shore power, and our fresh water tank was full. I noticed water pump very occasionally came on, just for a moment, even when we hadn't turned any faucets on. My first thought was a water leak, but I checked all the usual suspects and found none. Could there be a small leak under the floor? Or is this normal? Thanks for any suggestions.

[Bcborn]

We noticed that it would do the same momentarily during the night. We now turn it off when we go to bed.

No present leaks, Thinking it could be water contraction through change in temperature, no water leaks, so chocked it up as weak pressure switch or normal.

Ideas?

[creativepart]

If it does it so little that it doesn't wake you or bother you, and if you don't see any sign of a leak then it's not that big of a deal.

There is a pressure switch on the pump that you can adjust that can limit or even eliminate this... unless you have a real leak. But be forewarned, its a sensitive adjustment that if you get wrong can have unintended consequences. Like a pump not turning on when you open a tap, or a pump running after you close a tap.

It's not dangerous our something that can't be fixed if you get it wrong... it's just that it takes a fine touch to make very small pressure adjustments.

Look at your water pump, there will be a label with the model make and number. Then look up the pump on line and read about adjusting the pressure switch.

Many Winnebago RVs have a Shurflo 4008 pump. I know from experience it's easy to adjust, but it's also easy to go overboard and "adjust" it too much.

[Eagle5]

Mine too would do that. It is because the pump's pressure controller was set for too low a pressure. To fix this, I increased the pump's built-in pressure regulator with a 1/16" Allen Wrench and turned it tighter.
I tired of not being able to control the pump accurately, and the pump's noise, so I installed an:
Water Pump Variable Speed Controller for a 22M
Thanks, Eagle5

[Bcborn]

Those are some great options, thanks guys.

[Morich]

An alternate view?
Consider how the pressure switch works. It keeps the pump on until the pressure on the output side reaches the set level and then turns the pump off.
We know little about the parts on the trailer group but we have to assume it is much like the motorized where we have super nice detailed drawings of where the lines run so that we can see the route the water uses in the different modes, line pressure or pump pressure.
I feel there are two places which can explain why the pump will shut down as the set pressure is reached but then restart for just a short time later and repeat it all through the night.
But the details may vary for different RV, so it takes a bit of looking or checking to sort which is more likely in any given RV.
The easier one to spot and test is at the connection where the pressure water hose is connected. Looking directly into that connection we often see a small plastic disk which is held against the inside of the fitting by a small spring.
This small disk acts as a check valve to keep the pressure and water from the pump from just blowing out this connection when we have no hose connected and the pump runs!
If you have one of these, it is easy to see what might happen if the little disk is not sealing really well. Depending on line layout, if you push in on the little disk while the pump has pressure built, you will likely get a burst of air and then shortly after a jet of water and your pump will kick on to rebuild the pressure you have released!
If it leaks enough and your pump pushes enough air and water out, you may notice a bit of water in the wet bay, but how close do most of us look if we see water drops in the wet bay? I suspect most would ignore it and figure we dripped some!

A plastic plug screwed into the input port may stop the air leak and be an easy try??

A second and pretty common problem is one I suspect is likely but harder to diagnose and cure. But we do know lots of check valves at the water pump do give people fits when they start to let pressure go back through the pump! It often lets the fresh water tank fill and overflow when we are hooked to pressure water!

If we let the pump build pressure on the output side of the water pump and check valve but that valve lets pressure and water slip back through the check valve, it goes back into the tank and the water pump senses low output and starts to rebuild to the set pressure! No water leaks to spot but the water pump starts at times for no reason we know about!



Just picking numbers out of a hat, say the pump comes on when pressure goes down to 10PSI and runs until it reaches 20PSI on the output side? If that water and pressure leaks from the right side of this drawing back through the check valve at the pump, that 20 PSI it built at the right side is gone and the pump starts again?

Rebuilding the internal check valve in the pump or adding a second check valve in the output line may cure the backflow!

[Gunny Rio]

Many great comments here. I had the same problem a few weeks ago camping in PA. I couldn't find any leaks but every 5-10 min the pump came on for a second or two. Long story short, one of the shower faucets was just open enough to allow pressure to slowly bleed off (less than a degree or two). If this is a new problem I would first make sure all the faucets are completely closed.

[dougs]

thanks for the responses!