HOT water problem

Support your community
Advertise with us
shop deals on amazon
Shop deals on ebay
Plumbing Forums

Help Support Plumbing Forums:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
I

IHatePlumbing

Member
Joined
Nov 12, 2021
Messages
16
Reaction score
4
Location
Washington, DC
Hello - another day, another plumbing problem.

I had some plumbing work done recently and now I'm almost completely without hot water. I had a small section of galvanized pipe replaced at the main water entry point (before water heater) and also some flex pipe at the water heater replaced with hard copper piping. The expansion tank was corroded, and needed to be replaced, but the plumber didn't have the right one at the time, so he piped it without the expansion tank while a new one was on order. Everything was working fine after this. Plumber came back and put in the expansion tank and we've not had reliable hot water since then. Plumber came back out and said everything looked fine and advised me to call manufacturer of water heater. I got a new water heater in 2017 (50 gallon Rheem gas water heater). I called Rheem and they had me turn off the inlet valve to the water heater and turn on the hot water valve on a nearby faucet. I let it run for 5 minutes and it flowed very fast, but was not hot. Rheem said that the fact that water still continued to flow means that there is a problem with the plumbing. Also, all status lights on the water heater suggest that it is operating normally. Plumbers are coming back out, but they don't think it's a plumbing issue from the work they did. They want to check every fixture in the house to see where the water could be mixing. I found it interesting that the plumber held the outlet pipe at the water heater and could tell that it was at 70ish degrees.

I'm including some pictures of the piping at the water heater. Any help or suggestions?

Thanks,
Brian
 

Attachments

  • PXL_20220105_143921988.jpg
    PXL_20220105_143921988.jpg
    2.6 MB · Views: 29
  • PXL_20220105_143913640.jpg
    PXL_20220105_143913640.jpg
    2.3 MB · Views: 28
Symptoms certainly indicate a cross-over issue and it may be a mixing valve at one of your fixtures ( tub - shower or single handle faucet ). One of the experienced pros will be along to guide you on the diagnosis / isolation process.
 
Turn the water heater cold inlet valve off.

Turn the hot water valve off to the washing machine and disconnect the hose.

Now turn the valve to the washing machine hose back on to attempt to bleed the pressure down

If it’s crossing over it will have flow and never bleed down the pressure.


Now go to each fixture that has hot and cold water and turn off just one of its stop valves.

When you find the offending fixture that’s crossing over, the water flow will stop out of the washing machine hose. You may even hear the crossover flowing at the fixture as you turn it off.
 
Is there a routine to follow if the home does not have a washing machine ?
 
@Twowaxhack - I just saw your reply, but I did some tinkering before seeing it.

I turned off every single shut-off valve I could find in my basement and confirmed that all water was off at all fixtures on the top floor. Then on the main floor, just the toilet and sink in the bathroom are not linked to a shut-off in the basement. So, I didn't bother with the toilet, since it wasn't running. I turned the cold off just before where it connects to the sink and confirmed I didn't get any water when I turned the handle. When I turned the hot valve off, water still flowed, so I guess the valve is not functional at this point. So the only places water was not turned off is at the hot valve to the bathroom sink, the cold to the toilet, and the hot and cold at my basement laundry sink. There is no mixer valve at the laundry sink. The bathroom sink does have a mixer situation, but since the cold was shut off, would that affect anything?

I never got any hot water with all of the valves shut off. I let it run for a while too.
 
IHatePlumbing said:
@Twowaxhack - I just saw your reply, but I did some tinkering before seeing it.

I turned off every single shut-off valve I could find in my basement and confirmed that all water was off at all fixtures on the top floor. Then on the main floor, just the toilet and sink in the bathroom are not linked to a shut-off in the basement. So, I didn't bother with the toilet, since it wasn't running. I turned the cold off just before where it connects to the sink and confirmed I didn't get any water when I turned the handle. When I turned the hot valve off, water still flowed, so I guess the valve is not functional at this point. So the only places water was not turned off is at the hot valve to the bathroom sink, the cold to the toilet, and the hot and cold at my basement laundry sink. There is no mixer valve at the laundry sink. The bathroom sink does have a mixer situation, but since the cold was shut off, would that affect anything?

I never got any hot water with all of the valves shut off. I let it run for a while too.
Click to expand...

Just do what I lay out on post number 3 and report back.

You must be thorough or the test will not tell you anything.

They may have you crossed up at the water heater itself. They may have piped the cold water to the hot side and the hot water pipe to the cold inlet.
 
@Twowaxhack - I followed your instructions and it led to my main floor bathroom shower. It has a hot knob, a cold know, and a flow knob. The flow knob was closed, but the hot and cold were both open. When I shut those off, water stopped flowing out of the laundry hose.

But then after I put everything else back to normal, still no hot water. I checked the piping at the water heater and they were connected to the correct sides. Outlet pipe at water heater is lukewarm to the touch. Again - status lights on the water heater indicate normal operation.
 
@Twowaxhack - plumber just got here and pulled water out of the valve at the bottom of the water heater and read only 80 degrees. Could that still be a mixing issue or does that point to the water heater?

Thanks,
Brian
 
The drain valve is near the outlet of the dip tube. It’s not a good place to draw water from.

Draw a quart of water out of the relief valve and take it’s temperature. Write that number down.

A water heater should put out 70% of its capacity within 20 degrees of the thermostat setting.

70% of 50 gal tank is 35 gal.

You should be able to get 35 gallons of hot water within 20 degrees of the temp of the quart of water that you took from the relief valve pipe.

Make sure you don’t have a crossover before performing the draw test.

Make sure the thermostat is satisfied and the water heater is not heating. It’s ok for the heater to fire during the draw test. But the burner must be at rest when the test starts.
 
@Twowaxhack - if I understand correctly, my tinkering from above suggests there is no crossover. The plumber took the temperature at both the drain valve and the relief valve and got a very narrow temperature difference. It was 83 degrees at the relief valve and 70something at the drain valve. The water heater was set to 120 degree setting and it was satisfied during the test. He also turned the setting up to the next heat setting and the burner turned on for no more than 5 seconds before it was satisfied. I would have expected it to stay on for some time.

I'm sorry if my understanding of this is frustrating. I really have no idea how plumbing works.
 
And I'm back. Rheem sent out a gas control, but not the temperature probe, so the plumber changed out the control and of course it still doesn't work. Now, Rheem is sending out the temperature probe and has offered to pay up to $250 for the installation of the temperature probe. Plumber is saying it's a $600 job. What is a reasonable cost for this? Keep in mind, I'm in Washington, DC and labor is higher here than in more rural areas.

Should I just do it myself? My big concern with doing it myself is if it doesn't fix the problem.

Let me know your thoughts and thanks everyone for the help.
 
I always go where angels fear to tread so I'd recommend a DIY but that's just me. I have, on balance, come out ahead in the long run. If you are even considering a DIY you are probably okay. Do you have the tools necessary?
 
Update: The plumbers came back out and installed the temperature probe and it's the same problem. Rheem told me that the only other thing it could be if it's water heater related is the dip tube. But plumber tested temp at top and bottom and highest temp was 83 degrees, so could that really be the dip tube? What else could it be? Is there any chance it's the expansion tank? The issue coincides 100% with the installation of the expansion tank. I'm losing my mind here. My kids haven't bathed in over 2 weeks.

Brian
 
It’s the dip tube or you still have the cross connection or the control is bad.

Start with checking for the cross connection as you did before.

Then check the dip tube.

If those two check out then it absolutely has to be the controls of the water heater.

Make sure the dip tube is installed in the inlet that’s receiving the cold water. Very very important.
 
@Twowaxhack - here is the thing... everything was operating normally until the flex tubes were changed for hard copper and when the expansion tank was installed. The dip tube hasn't changed unless it was moved from one side to the other by the plumber who hard-piped it. My question is... is it possible that the change to hard piping or installation of the expansion tank damaged the dip tube? Plumber is trying to charge me for all this labor, but I just want to make sure it's impossible for them to have damaged it during installation of those items. If they were sweating pipes that were hooked up to the water heater, could this have damaged the dip tube?
 
I looked at your pic again. Your heater has those long nipples so I doubt the plumber melted the dip tube.

You could cut the hot pipe a foot or so from the water heater and connect a hose Bibb to the supply pipe from the heater. Or you could just clamp a hose onto it some how, doesn’t matter.

Then conduct a draw test and see if the water heater is functioning or not.

This eliminates your other plumbing as a possible cause, without question.

You must isolate and eliminate or you will be chasing your tail.
 
You must log in or register to reply here.

Latest posts

Back
Top