Resolved Only getting a trickle of water from the HOT side

[mnvelocitypilot]

Only getting a trickle of water from HOT side
I'd sure appreciate some ideas on this...

After camping a few weeks ago at a full hook up campground, I'm now only getting a slow trickle of water from the hot side in our 2000 Itasca SunCruiser and it's 2 year old Atwood 10-E hot water heater.

Here are some specific observations I've made...

• Start with main house tank EMPTY and HW tank EMPTY
• Fill the main tank. I hear the pump filling the HW heater tank.
• I'm pretty sure I can hear the HW electric heater working.
• Once main house tank is full and HW tank seems full (i.e., pump has stopped running), I get GREAT pressure out of the HW side for a few moments, followed by a copious amount of air, followed by just a trickle of water on the hot side. Cold side water flow & pressure are normal.
• Opening the HW heater pressure relief valve (on the heater), I get lots of high pressure water coming out of the pressure relief.
• After I do that (release some of the water from the HW tank via the pressure relief), I get flow from the HW side for a short period ... then back to just a trickle.

I tried to fix this by replacing the one way water valve that's on the input side of the heater. I thought that might have been damaged by the high pressure water at our last campground. No luck; same results.

It seems like there has to be a bubble in the HW heater that I'm not draining, or some sort of problem with the heater itself (like a second, internal, one way valve that's stuck). The fact that I can get normal pressure flow out of the HW side for brief periods seems to tell me that there isn't a problem with the HW plumbing lines. But, beyond that idea, which I don't know how to fix, I'm stuck.

Anyone out there ever faced this before? Any ideas? I'd be GRATEFUL!

Thanks much!
Dave

 

[Kevin D Pem]

Do you have bypass valves on the water heater, and if so are they both open completely.

 

[RandyB]

If your plumbing is equipped with a water heater bypass, it is possible that the outbound valve is partially closed.
Most units have 3 valve system. One on the inlet port, one on the outlet port and the third one is between the inlet and the outlet. Most often this valving is on the back side of the heater. It purpose is to allow winterization without filling the water heater.
normal operation: inlet and outlet open, bypass closed.
Gaining access to the back of the heater can be as easy as opening a door or lid, but also as difficult as removing some kitchen drawers.

 

[mnvelocitypilot]

Do you have bypass valves on the water heater, and if so are they both open completely.

Hi Kevin -

Yes I've got a bypass valve. Yes, at least as far as I can tell it's fully functional and in the correct position (positioned to NOT bypass the water heater). The valve stayed in the "water heater ON" position throughout this failure; at the last campground everything was working fine and we had good hot water. Then this failure; the water slowed to a trickle. As a part of replacing the reverse flow prevention valve on the input side to the heater I manipulated the valve to bypass the heater, and it worked fine in doing that. When I tested the system after the replacement I returned the valve to WH On position and found the same issue as before... a mere dribble of water on the hot side.

But ... thanks much for your question!

Dave

 

[Kevin D Pem]

Hi Kevin -

Yes I've got a bypass valve. Yes, at least as far as I can tell it's fully functional and in the correct position (positioned to NOT bypass the water heater). The valve stayed in the "water heater ON" position throughout this failure; at the last campground everything was working fine and we had good hot water. Then this failure; the water slowed to a trickle. As a part of replacing the reverse flow prevention valve on the input side to the heater I manipulated the valve to bypass the heater, and it worked fine in doing that. When I tested the system after the replacement I returned the valve to WH On position and found the same issue as before... a mere dribble of water on the hot side.

But ... thanks much for your question!

Dave

darn, was hoping for something simple.

 

[RKins]

I am going to assume that you had good hot water while camping a few weeks ago - do you have an outdoor shower wand in the wet bay? If so, did you use it and shut it off at the wand instead of the cold/hot mixing valves that feed the wand?

 

[mnvelocitypilot]

darn, was hoping for something simple.

Me too!

 

[mnvelocitypilot]

I am going to assume that you had good hot water while camping a few weeks ago - do you have an outdoor shower wand in the wet bay? If so, did you use it and shut it off at the wand instead of the cold/hot mixing valves that feed the wand?

Hi RKins - thanks for asking. Yes we do have an outdoor shower wand but no, I never touched it. But good question!
Dave

 

[RandyB]

Quote: I tried to fix this by replacing the one way water valve that's on the input side of the heater. I thought that might have been damaged by the high pressure water at our last campground. No luck; same results.

Have you double-checked the check valve (one-way valve) for installing in the proper direction? There should be an arrow or some other indication of the flow direction. If on the inlet side as you say, it should be pointing towards the heater tank. If on the outlet side, pointing away from the heater.
However, based on your trial of opening the pressure relief and you had good flow, I would suspect the check valve is on the outlet and should be pointing away from the tank, but might not be.

 

[mnvelocitypilot]

Quote: I tried to fix this by replacing the one way water valve that's on the input side of the heater. I thought that might have been damaged by the high pressure water at our last campground. No luck; same results.

Have you double-checked the check valve (one-way valve) for installing in the proper direction? There should be an arrow or some other indication of the flow direction. If on the inlet side as you say, it should be pointing towards the heater tank. If on the outlet side, pointing away from the heater.
However, based on your trial of opening the pressure relief and you had good flow, I would suspect the check valve is on the outlet and should be pointing away from the tank, but might not be.

Thanks, Randy. Yup, it's installed correctly. That's not the problem. Keep in mind that I get a strong flow at first when starting with an empty tank, and that the problem didn't change at all after I installed the new valve. But thanks for asking, sir! Any other ideas?