Water pump hums - no water pumping

[lezmark]

For the winter I left all the valves in the trailer open. Today was open her up day and I started out by draining the fresh water tank and refilling. That might be part of my problem. Anyway, once i was filled up I went inside to turn the pump on, while all the valves were open. I could hear the pump, just not getting water up. I know where the pump is, and i can touch it over a plastic shield in the front pass through hatch. Darned if i can figure out how to remove the shield. I am thinking there is air in the line. Who can help please?

[wolfe10]

When you say "all valves open" you need a faucet open to allow air to bleed out and on many RV's the "tank fill" valve closed.

[lezmark]

what I am thinking is that the pump lines lost a "vacuum" when i drained the tank with all the valves open. I tried leaving the pump on opening and closing the valves. Just had an idea of hooking up to city water and "burping" all the fixtures and THEN see if the water pump will work...

[garywilson]

Pump may have lost prime...although usually self-priming.
Mind did it last year.
Added water to the pump by pouring water in the winterizing hose.
Hasn't happened since.
Also, sometimes the screen in the pump bowl gets clogged, but I haven't experienced that yet.

[Bill Nourse]

I had the same problem. Turns out I did not put winterizing valve back in the right position when I started up. The pump was trying to take suction from the winterizing hose instead of the fresh water tank.

[MSchu]

My Shurflo 4088 did the same thing after being winterized. Mine turned out to be a stuck check valve, Once I got it freed up the pump worked fine.
I think that using air to blow out the lines last fall might have caused it, but it might have just been due to sitting for months.