fresh water tank issue/question

[scout_dad]

Hi there hoping for insight on these questions, have BH TT I have never put in any water in fresh water tank via water inlet, have always removed drain cap on tank when I winterized. I day last summer was looking underneath trailer and noticed the hose which looks like the hose that connect from the top side out side connection has a sharp bend in it near where it attaches to tank underneath.

I figure that I could loosen clamp cut excess off to do away with bend. I will have to drop tank because the clamp screw is at top, no room to get too:

Fast forward to this past weekend while I was camping was looking at hose again, moved it and heard gurgle noise like water in tank, removed drain cap and sure enough there was water coming coming, here is first question, is it normal to tank to fill up when you are connected to city water?

Second question, while I was disconnected from city water, I turn on pump and open faucet up to let water run it ran out but not very fast, but when I went outside of trailer I noticed water pumping out of the city water inlet where you put water hose too.
Could this be due to fresh water hose tank having kink in it, making it run out city inlet or another problem?

Like to use fresh water tank at some point but not if don't work right. Any help would be grateful.
Thanks

[Harvey51]

This sounds a little like my setup for measuring how much water is in the tank. I attached a 2 foot clear plastic tube to the tank drain routed upward so water doesn’t drain out. I can see the water level by briefly opening the tap.

[4x4van]

As Drew said, the water leaking back out of the city water inlet means a bad check valve in the inlet assembly.

Some RVs have only a gravity fill line to the fresh tank (sounds like that is what yours has, and it's kinked), others have a valve that directs the city water hookup into the tank (city tank fill), and some RVs even have both. In the case of a "city tank fill" valve, they can sometimes go bad, leaking water from the city hookup into the fresh tank even if the valve is turned off.

The only other way for the fresh tank to fill while using city water is a leaking check valve in the water pump itself. That sounds like your issue.

[scout_dad]

No worries, maybe I was not clear enough either, yes my trailer has separate connection for fresh, and city side. Basically you use a funnel, or hose attachment and put water in thru opening to fill tank for fresh water tank, so think it is the hose one side to tanks and other side inlet port.

Yea did not think it should have a bend in it like that.

[DrewE]

OK, I think the hose in question is the "gravity fill hose" (perhaps among other names) to fill the water tank from what you're calling the fresh water inlet. It should not be kinked.

What I meant by "water filling from the fresh water connection" is water getting into the tank from the (pressure) city water connection. That wasn't the clearest of wording, for sure. All I can say in my defense is that my RV has only a city water connection, with no separate gravity fresh water fill, and the tank is filled by fiddling with valves to direct the city water into it. (Well, technically I could also fill it with the winterize/suction fill port, pumping water into the tank from some external container, but that would be a fairly slow and cumbersome process for a tankful of water.)

[scout_dad]

Thanks DrewE,
The hose I am referring to is a larger hose, it attaches at one end of tank, it goes thru some insulation underneath and up, right above it is the fresh water inlet not city side. I would guess this is the hose that attaches to other side of inlet assembly, would have to pull off the connection to see.
YES the hose has a sharp bend in it, like if you bent a water hose in two to stop water coming out.

Also not sure what you mean, water is filling the fresh water tank from city side.
Thanks

[DrewE]

Water coming out the city water inlet would be due to the check valve in the inlet assembly being broken or out of position or otherwise not working properly. The first thing I'd do is see if I could tweak it with a finger or something. If that doesn't work, an easy quick "fix" is to screw a plug/cap into the hose connection so water cannot come out.

Water filling the tank from the fresh water connection generally means that either a fill valve is not shut (if you have such a valve, not all RVs do) or the check valve that's incorporated into the water pump is leaking. The latter is often caused by a tiny spec of debris in the diaphragm of the pump, and if so may fix itself with some pump usage or with disassembly and cleaning. If the pump works decently otherwise, and the check valve can't be cleaned/fixed, installing a separate check valve on the pump suction line is a reasonable fix too.

The other hose sounds to me like it may be the vent hose for the tank, though it's hard to say without more details on where it goes from or to. If it is the vent hose, you want it to have a high spot above the top of the tank to avoid having water overflow through it when the tank isn't full (and, potentially, to help avoid siphoning a good portion of the water from the tank). A small kink in a vent line isn't going to cause major problems; there's a lot less resistance to airflow than water flow for the same size opening. Of course, if it's pinched shut or nearly so, that's a different matter entirely.