Water Pressure Woes

[ln106]

Hey y'all. New to this place, but I figured I'd join as soon as I got stumped, and, well, that didn't take long.

I recently became the new owner of a 90s Japanese class C (similar in stature and construction to a Sunrader 4x4, lucky me)

After our first weekend out, I'm slowly learning just how much doesn't work. 3-way fridge is no good on DC, propane alarm (with solenoid shutoff) is worn out so I can't get any propane, shoilet doesn't flush (hopefully that's just from the missing 3A fuse for the Thetford, not something more complicated...) but anyways, all of that I think I have a handle on.

What's got me stumped is the plumbing gremlins.

There are three plumbing fixtures. A faucet with one hot/cold tilt and swivel handle in the kitchen sink, a faucet/shower with a single on/blend knob, and an outdoor shower with hot and cold knobs.

Initially, when I filled up the holding tank and turned the pump on, I was able to run kitchen cold, outdoor hot and cold. Suspecting the pump, I hooked up to a garden hose and got the same symptoms.

When we got back, I figured I'd try to sanitize the tank and also run the air out of the hot water system. I was hoping that would help everything work - maybe the hot water tank full of air was upsetting the balance in the plumbing system.

So I did that - filled the tank back up, pressurized, and opened the hot valve in the kitchen sink. I could hear it whoosh and feel the air being pushed out as the tank filled. And then I could hear the water coming up, and it seemed like the instant it got to the fixture, it stopped. Not only was there barely a drip through the hot, all of a sudden there was barely a drip through the (previously fine) cold as well!

The outdoor shower still works perfectly. Everything behaves the same whether I'm hooked up to city water or pressurizing the tank.

Any thoughts on things I should check? I can't find a check valve or pressure regulator anywhere in the system, although there is a bunch of plumbing in the cavity under the shoilet sink that I can neither see nor reach without punching a hole through the wall.

I also don't have a socket wrench big enough to pull the drain cap off the water tank (a small suburban direct vent) but I'll do that and see if there's any gunk in there...

[BobBeery]

I have not had this problem, but I might try shutting off the pressure and taking the kitchen fixture apart to clean it.  Sounds like some crud got in it.  An alternative would be to disconnect the water lines from the fixture, have a big empty pan handy, and BRIEFLY turn on the water.  If still no water, it's piping.  But if water comes freely, it's the fixture.  A new fixture at an RV store should cost far less than a home kitchen fixture.

[Maineah]

Try opening the over pressure tap on the water heater (small handle on the valve) that will let any air out. Is the outside shower and add on? There is no pressure regulator other than the pump cutoff switch (part of the pump) so be careful when connected to the house it will supply greater than the system is designed for. No ideal about the outside shower it is possible it has some kind of diverter valve system to default to the shower when it's taps are open otherwise you might not have enough water for two or more fixtures at the same time. 

[Utah-Clay]

Take off all the screens and aerators on the faucets, the little passages get plugged with sediment and hard water deposits. 

[ln106]

Thanks all. I'll try with the kitchen faucet first, I can get at both sides of the plumbing. The screens are clean, but it could be gunked up in the valve.