Can't fill the fresh water tank

[Lorelei56]

Hello! I have a 2016 174 BH. I was trying to fill my fresh water tank to do a sanitizing soak. I put the hose in as usual but it spit the water back out! I opened up the low point drains to ensure the tank was not already full, and also opened up the sink and shower faucets, thinking it might be some kind of weird airlock in the tank. Nothing worked. I took the hose out and filled it slowly and from a short distance so that if there were an airlock, it would let the air out while allowing the water in. I kept hearing the tank inside the camper do a "thump, thump." Still the water was spit out. Nothing is leaking on the inside that I could see. I inserted the hose in the supply valve where you would hook up to if you had a water supply at a campground. The water flowed normally from that source. The water pump works, sending what little water that was in the tank to the faucets.
I've done the water system sanitizing many times before and all the valves were correct for the WH bypass but I've never had the freshwater tank just reject any water. I called the camper place and they said something about a check valve - does that sound right? Is there something I can do before I have to take it in? Thanks, and I hope y'all are staying healthy and safe.

[WeRJuliian]

The check valve is supposed to prevent the water from the city connection flowing into the tank.
If you can hear a "thump", that suggests an air lock somewhere, or a blocked overflow pipe....
Have you tried running the pump while you fill?

[distracto]

The fresh water tank is under the bed, take out the two screws of the plywood, lift it up and you may be able to see if there is any blockage in the fill hose.

There shouldn't be any valves for the fresh water gravity fill, there weren't any on my 2018 174BH

[Jagiven]

Sounds like you have a gravity fill port. Have you verified that the overflow vent under the TT is plugged? Air should escape from the overflow vent under the TT.

Has someone added a valve to the overflow vent, to prevent the dreaded siphoning issue?

If you have a gravity fill port, there is no check valve in the piping, as it is an open system.

[Lorelei56]

I unpiled our bed and took out the two screws above the water tank. Lo and behold, the overflow hose was both kinked because the tank shifted and it had a lot of biological growth clogging up the opening. I didn't even realize there was that tiny port to the left of the water intake port. I unkinked the hose, put some boards in the back of the tank under the strap to keep it from sliding back as much, and brushed out the mold from the overflow hose - yuck! The tank actually was about half full and the sides were bowed in from the air lock, so it wouldn't drain. Now everything is getting good and sanitized. Thanks again - y'all saved me lots of money. I don't work now so that's really appreciated.

[Jagiven]

Originally Posted by Lorelei56

I unpiled our bed and took out the two screws above the water tank. Lo and behold, the overflow hose was both kinked because the tank shifted and it had a lot of biological growth clogging up the opening. I didn't even realize there was that tiny port to the left of the water intake port. I unkinked the hose, put some boards in the back of the tank under the strap to keep it from sliding back as much, and brushed out the mold from the overflow hose - yuck! The tank actually was about half full and the sides were bowed in from the air lock, so it wouldn't drain. Now everything is getting good and sanitized. Thanks again - y'all saved me lots of money. I don't work now so that's really appreciated.

Glad you were able to find the issue, and it was a simple fix.

[JFlightRisk]

Lorelei56, you're now classified as an expert RV technician! Good job finding the issue, and repairing it.

[distracto]

Glad it worked out! Those 174BHs are great little trailers!

[Screwby]

Nice! Just saved yourself like $175/hr. labor from a dealer

[Vista]

Thanks for coming back to post your resolution.