Water pump extra tube

[cwalther1]

I filled my water tank and turned on the pump. The faucets (all of them) continually spit out air and very little water. I found the secret compartment where the water pump is hidden in the master bedroom on the right side of the bed. No leaks anywhere that I could see. Started pulling on various hoses and found one uncapped coming off a pump connection. Luckily it had a valve on it and I turned the valve off. Problem solved, pump now actually turns off after reaching correct pressure and I have good flow on all faucets. My question is what could this extra hose be for, possibly to blow out the lines while winterizing ? I felt around in the dark void where the hoses go behind the pass through storage up front and couldn't feel and loose connections. The last time I tried to use the pump, it ran continually and eventually I had water running out from underneath the bed. Thought I had a busted line somewhere. The uncapped hose must have been shooting water out. Anybody have any insight as to what or why this uncapped hose is down there ?

All comments appreciated.

[Oliver]

Sounds to me like it is probably the suction hose you stick into a a gallon jug of rv antifreeze for winterizing.

[660catman]

^^^^^ this. It’s the suction hose for antifreeze. Once you closed that valve it no longer sucked air.

[dagst1]

The valve at the end of that line turns one way to pull water from tank and the other way to pull antifreeze from a jug. If it was partially turned it would pull water and also air.