Hot water heater problem

[upstech76]

Helping a family member work on their TT. They have little to no water flow through the hot water tank. I've checked all the obvious and pretty sure a check valve is stuck but not sure where it is located. Here is what I know.

1. Water Input (bottom) valve is open.
2. Water Output valve (top) is open.
3. Bypass is closed (when I do open this water will bypass the heater and flows out the hot side of the kitchen/bath tap.
4. Hot water flows from the blow off valve when opened.

So the problem as to be between the tank and the T for the bypass right? Would the right angle piece coming from the tank contain a check valve? Would the output valve have a check valve in it?


Thanks in advance.

Michael

[C-Leigh_Racing]

upstech76 wrote:
Led 67, this TT was recently purchased so I don't know any background on the unit other than it doesn't have a anode rod because someone installed an electric Hot Rod kit in it.

C-Leigh Racing, if I recall correctly they are metal shafts on the valves and both feel normal when opening/closing them. When the bypass is open, the water is bypassing the heater and is cold at the taps.

The next trip out I am going to disconnect the hot side and allow water to flow into a bucket to check and see if I have good flow coming out of the heater. Hopefully this will narrow it down between the right angle fitting and the shut off valve.

Ok, I see what your saying, so the bypass when open, is just letting the water flow past instead of going into the water heater & then back out. That how it should be.

Next thing, those two on & off valves, you can take the screw out of that handle, pull it off & then theres a cap you can screw off of the valve body, then you can screw the shaft out.
On the end of that shaft, there should be a rubber washer that when you screw the shaft in, that rubber washer would close off a opening down in that valve body to shut the water flow off. Could be, that rubber washer has come apart & blocking the passage way & preventing water to flow into the heater.

Theres two types of valves that look like that, one will have the shaft with the rubber washer on the end, that you'll need to rotate several time to open or close completely, then theres another that will be maybe a 1/2 turn rotation to open or close & theres a ball inside of the valve body with a hole threw the middle.
Both types of valves will work the same, but will be less chance of the ball type to have a blockage, unless something was in the water lines from the pump to that ball valve.

You can unscrew the water line fitting where it connects to the brass elbow on the water heater tank & see right quick if you have any fresh water flow going into the tank.
You could as well while you have that fresh water line off, open one of the faucets on the hot side & blow into the heater tank & see if you get any flow from the heater doing that.
Neil

[Old-Biscuit]

IS the WH an Atwood or Suburban??

IF Atwood....Hot Rod kit OK as no anode rod is needed

IF Suburban.......hopefully previous owner bought the Hot Rod kit with the small anode on the end of element....it's a small one but better than nothing.

Pull the Hot Rod out/drain/flush WH....problem could be from sediment due to lack of routine draining/flushing due to Hot Rod kit. Folks tend to just ignore WH once those are installed.

[wa8yxm]

It appears that with no pressure in the water system you can unscrew from the top 90 degree outlet adapter..

Hook up a hose by whatever means you choose (Adapter and garden hose. Or just clamp a hose over it) then close the bottom valve. Pressurize the system (City or pump) (Oh, close all 3 valves) and then open the bottom vavle with the hose outdoors where it won't make a mess. How is the flow?

If Good, Problem is one of the valves or inlet

If bad, Problem is water heater,, Now since I do not think there is a check valve post and we will do our best.

If you get poor flow in this test close lower valve, drain water heater (outside drain) reconnect the top line and disconnect from the bottom line.

Adapt the hose to the line, open the lower valve and check flow

If flow is good, Problem is heater, If bad, Lower valve.

The rest of the system you have already checked.

[upstech76]

Led 67, this TT was recently purchased so I don't know any background on the unit other than it doesn't have a anode rod because someone installed an electric Hot Rod kit in it.

C-Leigh Racing, if I recall correctly they are metal shafts on the valves and both feel normal when opening/closing them. When the bypass is open, the water is bypassing the heater and is cold at the taps.

The next trip out I am going to disconnect the hot side and allow water to flow into a bucket to check and see if I have good flow coming out of the heater. Hopefully this will narrow it down between the right angle fitting and the shut off valve.

[C-Leigh_Racing]

Those two valves in your pic, the inlet & outlet in the lines, do those have metal shafts or are they plastic shafts like the handles.
If they are plastic shafts, it could be the shaft on the outlet side has broken & when you screw the handle out it is not opening the valve.

You listed you could open the bypass valve & could get water flow in the bath room & kitchen, is that water flow hot or cold water coming out, which you could only tell if the water heater was on.
Neil

[Led_67]

Question...What maintenance does your family member have for this TT. If there is an anode rode then when was it replaced last ?? If not replaced then could it have a floater blocking the outlet during flow or possibly gotten as far as the valve ??
Just my .02 Good Luck

[64thunderbolt]

duplicate post

[64thunderbolt]

Old-Biscuit wrote:

64thunderbolt wrote:

Old-Biscuit wrote:
Before messing with the PEX clamps/fittings check the tank nipples.

Your type of valves rarely fail stopping flow when opening.
If they fail it's usually that they don't fully close and leak thru.
When you open hot out valve and get flow then it stops sounds like the symptoms of a check valve problem.

Some rv builders installed check valves even with the 3 valve systems.
Even put them in the cold inlet nipple vs hot outlet nipple.

Next time out to trailer........open WH tank PRV via lever then turn on pump.
If you get steady flow out PRV then cold inlet isn't problem. One less thing to check/worry about. Then you problem is on hot outlet side

He said he had flow from the PRV. The hot supply valve is suspect. Whenever I replace I use 1/4 turn ball valves.

OK.....missed that on initial post
Still think the problem is at the tank outlet and not with the shutoff valve

Could be. In 15 yrs of 5th wheels I've never had this issue so I'm not sure theres a check valve in that fitting or not.

[Ex-Tech]

enblethen wrote:
Look closely at the incoming cold water line. It could have a check valve. They don't look like much, just a short nipple on outside but is actually a check valve. It is use to prevent hot water from backing into the cold water line.
You could remove the drain plug and see if you get good water flow into water heater.
Qest check valve

Since the OP stated he has pressure from the pop-off valve, that would indicate cold water is entering and pressurizing the tank.

[Old-Biscuit]

64thunderbolt wrote:

Old-Biscuit wrote:
Before messing with the PEX clamps/fittings check the tank nipples.

Your type of valves rarely fail stopping flow when opening.
If they fail it's usually that they don't fully close and leak thru.
When you open hot out valve and get flow then it stops sounds like the symptoms of a check valve problem.

Some rv builders installed check valves even with the 3 valve systems.
Even put them in the cold inlet nipple vs hot outlet nipple.

Next time out to trailer........open WH tank PRV via lever then turn on pump.
If you get steady flow out PRV then cold inlet isn't problem. One less thing to check/worry about. Then you problem is on hot outlet side

He said he had flow from the PRV. The hot supply valve is suspect. Whenever I replace I use 1/4 turn ball valves.

OK.....missed that on initial post
Still think the problem is at the tank outlet and not with the shutoff valve

[64thunderbolt]

Old-Biscuit wrote:
Before messing with the PEX clamps/fittings check the tank nipples.

Your type of valves rarely fail stopping flow when opening.
If they fail it's usually that they don't fully close and leak thru.
When you open hot out valve and get flow then it stops sounds like the symptoms of a check valve problem.

Some rv builders installed check valves even with the 3 valve systems.
Even put them in the cold inlet nipple vs hot outlet nipple.

Next time out to trailer........open WH tank PRV via lever then turn on pump.
If you get steady flow out PRV then cold inlet isn't problem. One less thing to check/worry about. Then you problem is on hot outlet side

He said he had flow from the PRV. The hot supply valve is suspect. Whenever I replace I use 1/4 turn ball valves.

[Old-Biscuit]

Before messing with the PEX clamps/fittings check the tank nipples.

Your type of valves rarely fail stopping flow when opening.
If they fail it's usually that they don't fully close and leak thru.
When you open hot out valve and get flow then it stops sounds like the symptoms of a check valve problem.

Some rv builders installed check valves even with the 3 valve systems.
Even put them in the cold inlet nipple vs hot outlet nipple.

Next time out to trailer........open WH tank PRV via lever then turn on pump.
If you get steady flow out PRV then cold inlet isn't problem. One less thing to check/worry about. Then you problem is on hot outlet side

[Dutch_12078]

Most hardware and home improvement stores carry one of several brands of PEX push-on fittings, including inline shutoff valves, that do not require any tools except a sharp (utility) knife for installation. Common brands include SharkBite, Gater Bite, Watts, and Sea Tech.

[upstech76]

Thanks everyone for the advise.

powderman426, I wasn't aware a valve of this type could fail but I really suspect that is what is happening. With all others in their normal operating position, as I open the hot side valve I start to get flow then it suddenly stops.

enblethen, its definately not on the supply (cold) side because I have plenty of flow when opening the blow off valve outside.

Old-Biscuit, I plan to investigate the output fitting on the tank closer but I couldn't find a flow direction stamped on it so I didn't think it would have a check valve in it.

dbbls & RoyB,
The input/output (cold/hot) valves are not the 90 degree shut off type valves. These turn approximately 360 degrees from full open to full close (much like a standard outdoor faucet.

It will be a couple weeks before I can look at it again but hope to solve the issue soon. Any advice on dealing with Pex tubing since I don't have a crimp tool for it?

Michael