Hello everyone, need a little help! ...

[MrB18]

Hello everyone, need a little help!  I have a 2003 Sundancer 300 and have rarely used the on board water system since I always hook up to water at our dock as well as when traveling.  Unfortunately it is that time of the year on the Great Lakes and need to winterize my water system.  I disconnected my shore water and turned on my water pump breaker and my pump started to run continuously with or without any faucet open.  When I do open a faucet no water comes out even though my level on the panel says I have 1/2 tank.  Any one have an idea as to what is going on?

Thank You

Allen 

[wingless]

My speculation is that there is air in the system, so the pump cannot pressurize enough to make the switch "happy" to turn off the pump.

If the parts are working then opening the fresh water taps should permit the pump to draw in water from the tank, distributing it to the taps until normal flow is established.

Once normal flow is established, then shutting off the taps should permit the system to pressurize enough to make the switch happy and shut off the pump.

[wingless]

It is possible that the tank level sensor is bad, showing water present when empty.

An easy check is to add ~5 gallons of water to see if that effects the problem.

[MrB18]

Thank you heading to the Boat Sat morning and will try your suggestions, It looks like there is a vent for the tank and was thinking it may have a spider web blocking it not allowing air to back fill the tank.

[wingless]

Yes, a blocked vent could cause the problem.

FWIW, when I add fresh water I overfill the tank, purging the vent of any obstructions. I then operate / discharge fresh water restoring to a normal level.