Check valve on city water inlet line? De-winterizing headaches.

[Dipodomys]

Getting ready to head for Bears Ears for our first trip of the season, and looks like we may be going with bottled water. After filling the water tank and turning on the pump, I can't pressurize the system because water just pumps out of the city-water inlet on the outside of the camper.

Last fall I winterized the camper by draining the water system at every available outlet and blowing out the system with an air compressor attached to the city water inlet. I'm pretty sure I had the faucet open when I started the air, but if I didn't then that might be how I messed up and broke the check valve. At any rate, I'm assuming the check valve is bad now and needs to be replaced.

Where is it? The camper is a 2017 Fleet (front dinette). Inside the cabinet, I can see where the city-water line Ts into the outlet from the water pump before that line enters a manifold. I can't see anywhere I check valve might be located, however. I've attached a photo where you can see the entire city water line from its attachment on the side of the camper to where it Ts into the pump outlet line on its way into the manifold. The second photo shows the water pump. The outlet line is on the left side and flows directly to the T fitting with the city water line in the first picture. I'm obviously missing something, and probably something obvious, but I can't figure out where that valve is!

 

[Dipodomys]

Related question: It occurs to me that an air/water tight cap on the city water inlet (where a hose would attach) could allow me to pressurize the system and use it as normal until I can replace the valve. Can you see any potential problems with doing that?

 

[Jon R]

A cap should work fine. I would install it as water is running out to try to minimize the amount of air in the line.

 

[Bigfoot Dave]

The cap should do fine. My city water inlet would drip sometimes after winterizing/dewinterizing. I just keep the plug screwed in.
Most city water inlets have a dome shaped rubber plug attached with a spring to the inside of the inlet. Blowing air can displace the domed plug and it won't seal. If you look closely at the inside of the inlet you can sometimes poke the dome back into place.
Happy Easter, Bigfoot Dave

 

[Dipodomys]

The cap should do fine. My city water inlet would drip sometimes after winterizing/dewinterizing. I just keep the plug screwed in.
Most city water inlets have a dome shaped rubber plug attached with a spring to the inside of the inlet. Blowing air can displace the domed plug and it won't seal. If you look closely at the inside of the inlet you can sometimes poke the dome back into place.
Happy Easter, Bigfoot Dave

Thanks, Dave! That was just what I needed to find the thing. We just got back from our trip to Bears Ears and a cap over the city-inlet allowed us to use our water like normal, so that's a good thing to have around for a quick fix in any case. I had already drained all the water when I saw your message, so I'll try to poke it back into place and see if it'll hold pressure when the weather warms back up a bit.

 

[Dipodomys]

Update: I may not bother fixing that valve if poking at it from outside the city-water inlet doesn't do the trick. I had to go online to find a male-threaded cap, but now that I have one installed and the plastic door will shut and lock with the cap in place, I can't really see how a working valve would be any better.