Very confusing water issue - not flowing to some faucets after de-winterizing

[Airmon]

Hi all, 

We're in a 2003 Southwind 32' Class A. We have spent most of decade on the road as full timers ( the last couple of years sharing that with a diesel trawler doing the great loop ) so we're not noobs, but for a variety of reasons we've been stationary in Virginia for the last year or so. 

While we're in southern VA and it's not as cold as some parts of the states, winter temperatures below freezing are enough of an issue that we winterized the RV for the first time late last year. 
The one previous time it was winterized was when we bought it about eight years ago and that was done with the pink non-toxic antifreeze. It took us FOREVER and several tanks ( 100 gallons ) of water run through everything to get the taste of that antifreeze out of the system. I have to use that on our boat when we winterize and I rather hate that stuff. I'm not even sure the well here at the house has enough capacity to run a few hundred gallons. 

So this year I got a hookup to use my air compressor to blow the water out of the lines.
I drained all the liquid from all tanks and the water heater, and as much water as I could get from the low point drains.  I then hooked  the air line up to the city water inlet.  With the compressor regulator set at about 30 PSI I proceeded to blow out all the lines until I got air out of all water outlets. Then pink antifreeze into all the traps and a gallon or so into the black and gray tanks.  Everything seemed fine and the RV sat in the yard until I went to get her ready for a short trip this spring. 

I added water to the tank, flipped the pump on and purged the air from the water heater, low point drains and the outside rinse faucet. So far, so good. 

Then, I went inside to start purging the lines to the sinks ( bathroom and kitchen ), toilet and shower. 
The shower worked normally, but the other three...didn't. The kitchen sink and the toilet have basically zero water coming out of them ( the kitchen faucet gurgles a bit sometimes when the valve is open ) and the bathroom sink flows a bit, maybe 30% or something, but not always, just sometimes. It's the same for the hot and cold water in both faucets, despite having pressure in the water heater tank. 

Ambient temps were in the 60's, so there's no water frozen somewhere. There's no break, because there's no water leaking and the pump isn't cycling unless I open one of the other, working, water outlets. 

Just no water coming out of the faucets and the toilet. Could there be check valves somewhere that are stuck? Any idea where I'd look? Some of the lines are absolutely inaccessible under the floor and there's no way to replace or get to them. 

I'm open to suggestions on where to look or how to diagnose this, because I got nuthin'. 

Thanks!

[rpnelson11]

That isn't making sense to me either.  The only thing I can think of is your water tank may be empty.  Try adding more water to it and be sure the tank drain is closed.

[Travelin2]

Sounds like the valves on the back of the water heater may be positioned incorrectly.

[Travelin2]

Sounds to me like the valves on the back of the water heater are positioned incorrectly.

[bobndot]

Once you check all faucets screens to be sure they are clean , i would drain the system.  
Then I would blow compressed air through the lines as well as the vent tube next to the gravity water fill port. 
 Have someone open each faucet one at a time to see if air flows out.    

  A dirty pump filter will reduce water flow and allow enough pressure for some faucets while not others.   
 

 When manufacturers drill holes in fresh water tanks to install fittings they sometimes leave plastic debris inside the tank.   Over time , that debris can find its way into a system.     
   There could a clog at an elbow fitting where the compressed air might dislodge it while water pressure did not.   

[opnspaces]

I think these systems are pretty basic with the only check valve being in the water heater. That check valve can come apart and pieces will flow downstream until the first 90  degree bend. But you have no cold water flow so that's probably not it.


When you turn on the kitchen faucet does it  sputter and does the water pump run continuously like the water is flowing somewhere?
Maybe try disconnecting the tubing at the water pump and at toilet and use your compressor to blow air backwards toward the pump.

[MNtundraRet]

It almost looks like the line to the toilet and kitchen may be clogged with calcium build-up caused using hard water over the years. If you had a leak, it would have shown up by now. 

[MNtundraRet]

It looks like the only thing you haven't tried is to hook up to an outside water spigot, or pump water through the normal water intake connection. That should release as stuck intake valve.

My motorhome was a 2003 . You would have the same system as mine. There has to be a bypass valve somewhere in your MH. 

[Airmon]

I will give that a shot. I didn't think if it in part because we're so rarely hooked up to city water. 

[Airmon]

Well, that seemed like a good idea, but no change. No water at toilet and kitchen. I confirmed no water pressure/flow in the lines to those items. 

I also checked the shower again, since it's the only outlet that still has the original two knobs for hot and cold, the sinks have newer faucets with single levers. Water is indeed coming from both hot and cold. 

There is no check valve under the sink. 

When the weather warms again I'll take apart as much of the wet bay plumbing as I can and see what I can see, but there's not much back there. Most of it is under the floors somewhere. 

[Ldfeat]

Make sure both of the outside shower faucet-knobs are off. I've read that this can cause similar problems. Even if the shower-head shut off-valve is off while the faucet knobs are on, can cause this issue.  Good Luck! Larry, 2014 Reyo P

[Airmon]

They're off, though that doesn't make any difference on our RV. 

[MNtundraRet]

My Bypass valve was found under the kitchen sink. I can't believe you don't have one.

[Airmon]

I'll look. 

[RICHB1]

Before tearing up the floor, try disconnecting the faucets and see if you get any flow.  Also, you may try blowing out the lines backwards or forward and see if you get any air flow.

Rich