Another drain issue

[azfiredog300]

Hey guys, didn't want to hijack someone elses thread so figured I should start a new one. in looking at other threads I haven't been able to find my answers.

When I am hooked up to city water or turn on my own pump all the water drains out of the drain tube. I have checked all the valves to make sure that the right ones were opened and the right one was closed but haven't been able to figure it out. It worked well for several years but this year its giving me a headache, any ideas?

[Inland RV Center, In]

Originally Posted by azfiredog300

Hey guys, didn't want to hijack someone elses thread so figured I should start a new one. in looking at other threads I haven't been able to find my answers.

When I am hooked up to city water or turn on my own pump all the water drains out of the drain tube. I have checked all the valves to make sure that the right ones were opened and the right one was closed but haven't been able to figure it out. It worked well for several years but this year its giving me a headache, any ideas?

Which exact drain tube, since there are several.

Andy

[ventport]

If you mean the drain tube under the trailer, you may have left the drain valve open that should be closed when the trailer is in use.

[azfiredog300]

the drain tube that normally empties my water tank when I am done with a trip. Thinking it was the valve itself I already took it apart and replaced all washers but still having problem when system is under pressure.

[TG Twinkie]

There should be no pressure in the fresh water tank, since it is gravity fed to the pump intake. If you fill the fresh water tank. Does water run out the drain valve? Even when closed?
It sounds like the check valve in the pump may be bad or have something in it where it won't seal.
When you are on city water, the plumbing system is pressurized throughout the coach. With the exception of the line between the FW tank and the pump.
Does your fresh water tank fill when connected to city water? If not. I would say the check valve in the pump is leaking slightly and with the drain valve open it is keeping up with the leak thru the pump.
I would disconnect the water line at the tank and cap it off temporarily and see if the water stops draining from the tank.