caveating water pump?

[dfrank]

Sorry I cant edit the auto corrected title. Should read cavitating, which apparently isn't a word. Cavitate doesn't seem to be a word either, though cavitation clearly is.

I just replaced my water heater in an older lance, (with a used one that I can't get to light, but that is another thread, maybe)

I filled the tank post winter and I just hear air bubbles in the water heater, and a mix of air and water coming out of the faucet. It won't really flow just straight water.

The pump won't build pressure and shut off.

It sounds like it is cavitating, or moving air. AM I supposed to purge it? Not seeing any bleeder screw type thing.

Did I do something wrong winterizing?

One other possible factor: The keys to the tanks went missing for 2 weeks, and I tried filling the system via hose to kitchen sink faucet. In retrospect, I bet I was forcing the pump backwards to do this. Might this have caused an issue?

Thanks,

 

[simple]

Do you have clear lines so you can see water going from the water storage tank to the pump? Did you double check that all the inline valves are open?

 

[Scoutn79]

Do you have enough water in the fresh water tank to keep the pump from pulling air? I there a loose fitting/crack in a pump supply line/pump allowing the pump to pull air? Can you get the cold water to flow correctly? How long did you let the pump run to bleed the air out of the system?
Darrell

 

[Jonstoy]

I would also check the pressure relief vlave on the hot water tank. I know for my own winterized hot water tank when I drain the water I open the relief vlave to allow more air to get behind the water to purge the water out of the tank quicker. It could just be that you need to close that vlave.

 

[dfrank]

Thanks. I've opened and closed the check valve on the water heater tank.

There is no bypass valve or any valves on the inside of the water heater.

fresh tank is 3/4 full.

I'll try hooking up the city water connection. I've never used this.

Maybe it will burp the pump.

Its odd that it cant burp itself. It pushes air and some water out any of the faucets, but wont build pressure or run without sputtering.

I've let it run for ten minutes at a time on 3-4 occasions. I dont want to burn it out if its semi dry in the pump.

 

[Scoutn79]

It still sounds like you have a leak on the vacuum side of the pump, a fitting, cracked hose or pump crack. Any leak on the pressure side of the pump will be a water getting out not air getting into the system (assuming all air is purged which shouldn't take but a minute or two.) Think of it this way, even a small water pump that moves 1 gallon a minute can fill a 1/2"id tube 1100+ ft (in theory) long per minute so it doesn't take long to purge your camper line.
Water molecules are many times bigger than air molecules so a crack can let air in but won't let water out if it is small enough.
If you didn't put RV antifreeze in your water lines over the winter you may have cracked the pump housing.
I would try another pump...maybe a friends who will let you borrow from their camper. We carry a spare pump just in case one freezes on us Elk hunting.

Darrell

 

[simple]

Did you figure out what what the problem was?