Demand Water Pump Questions

[tdbennett]

I've read some of the FAQS, but still have questions. I'll start by telling what I did, probably not the smartest thing.

We were getting some freezing temps here in the Mojave desert and I got concerned about freezing pipes in our RV. the plan was to go to Laughlin, NV over New Years, which we did, and I did not want to winterize since it was within a month of use.

I drained the fresh water tank and used the water pump until I got mostly air coming thru.

When I filled the tank prior to our trip I turned on the pump and opened the faucets one at a time to get flow. Now the pump runs a long time and any faucet gets a good flow the first time I turn it on then it slows to a dribble, if any at all, and the pump runs continuously. Works fine on city water. I have no idea what I screwed up. 

Any help is appreciated

 

[tdbennett]

Yes, I now realize I posted this in the wrong place

 

[Karl]

Sounds like you might have some ice crystals or chunks which congregated on the pump inlet filter, faucet screens, or elsewhere in the plumbing. I'd try warming things up in the outside bays and see if the problem doesn't clear itself in time.

 

[Bob Buchanan]

I drained the fresh water tank and used the water pump until I got mostly air coming thru.

Any help is appreciated

When you drained, did that empty the hot water tank? If so, it would take the pump extra running time to refill -- and reduce the pressure to an open valve during the process.

I replaced a water pump a couple of years ago -- so would agree with Karl that you take a look at the inlet filter on the pump. Mine was a mess at the time. I also replaced filters at each faucet, and they had enough built up to slow the flow consideralby.

 

[Karl]

When you drained, did that empty the hot water tank? If so, it would take the pump extra running time to refill -- and reduce the pressure to an open valve during the process.

Good point, Bob! Also, draining the system, especially the water heater, may have caused hard water deposits to flake off and cause clogs.

 

[tdbennett]

I don't know if that drained the hot water tank. I did forget to mention that everything works fine on city water. will it hurt to let the pump run and just keep bleeding the faucets?

 

[Gary RV_Wizard]

will it hurt to let the pump run and just keep bleeding the faucets?

No. Modern demand pumps can run dry or semi-dry for a long time without damage. I wouldn't let it run for hours, but 15-20 minutes won't hurt a thing.  And if you get occasional spurts of water, it can probably run longer than that. Otherwise let it cool a bit before re-trying.

It's possible the pump lost its prime, though they are supposed to be self-priming. You may have to inject a bit of water diretcly to the pump inlet to get it restarted.

Since it works fine on city water, the lines must be full and (if the hot water taps run OK) the water heater tank full. Therefore I would guess the problem is either at the pump or the line to the tank from the pump. Neither of these are part of the system when on city water..

 

[tdbennett]

Thanks Gary, I'll see if I can get it working this weekend.

 

[Lowell]

If the pump has lost its prime and is having difficulty getting water to it intake, you might aid it by using a wet/dry vacuum.  You would need to put the intake hose of the wet/dry vacuum on an open faucet and seal around the faucet as best you can.  You could probably use a plastic bag for that wrapped around the faucet and spicgot and vacuum hose.  Turn on the pump and then turn on the vacuum.  It should pull water from the tank,  through the pump, and to the faucet.

 

[KodiakRV]

If the pump has lost its prime and is having difficulty getting water to it intake, you might aid it by using a wet/dry vacuum.  You would need to put the intake hose of the wet/dry vacuum on an open faucet and seal around the faucet as best you can.  You could probably use a plastic bag for that wrapped around the faucet and spicgot and vacuum hose.  Turn on the pump and then turn on the vacuum.   It should pull water from the tank,  through the pump, and to the faucet.

Is that a high-falutin' way of saying you could suck on the spigot?  ;D

 

[Lowell]

Is that a high-falutin' way of saying you could suck on the spigot?   ;D

I guess it is. 

 

[tdbennett]

Thanks for all the advice and help. I found the problem, line from the tank to the pump is kinked and pump can't draw enough water to keep the line charged. I have some other small warranty issues to fix so I'll let the dealer fix it.

And, yes, I did suck on the spigot