We are currently doing a full en-suite bathroom remodel. About 2 weeks ago all of the plumbing was completed and about the same time we noticed that we weren’t getting as hot of water in the other bathroom we have been using as well as the kitchen sink, etc. I gave it a few days and no change so I called the plumbing company that installed our 50 gallon Rheem Pro atomospheric tank in late November 2017 as I figured something might be faulty.

They came this morning and as usual, everything seemed “reasonable” to him upon inspection and the tank fired up after about 6 gallons of water was run through the shower head. He adjusted the mixing valve on the shower to allow for a bit more hot water. Stated he felt it was our consumption which was causing the “lack of hot water”. He didn’t think it would be the dip tube cause the tank is so new.

This evening we were doing dishes and had the faucet cranked to full hot and we were getting luke warm/cool water. I checked the tanked and the burner wasn’t even on. I adjusted the thermostat and it kicked in.

I’m at a loss here and quite annoyed that despite’s having the tank inspected we are still experiencing issues. Could the new plumbing be causing issues or is it entirely conincidental? FYI the water lines into the bathroom from prior to the renovation were used just adjusted as required. The water main was turned off multiple times over several days during the plumbing install.

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    What is the thermostat set to now? Is the heater working better with the new setting? Commented Oct 16, 2018 at 10:45

1 Answer 1


Probably the temperature in the boiler is set too low: you should keep it, at least, at 70°C to have enough hot water because if you keep it lower, cold water coming inside the boiler will cool the water present quickly.

Another option is that the anti-scald automatic valve has gone bad (or is poorly set).

  • Recommendations I see are to set the temp in the tank to a "minimum" of 60 C (140 F), which most people respond to by setting it to exactly 140 F, but if one is running out of hot water then one could set it higher. Of course, an anti-scald shower valve would be essential if the temp is set at even 140 F. The problem here does not seem to be running out of hot water, but the failure of the heater to keep the water at the set point, at least at a "lower" setting. Most tank heaters have a "recommended" setting indicated on the dial. Commented Oct 16, 2018 at 10:33
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    The thermostat was set at 150. This morning I had a Luke warm shower again (valve cranked to hot) and the temp from the sink hot only was more or less the same temp. I “cycled” the thermostat and the tank did a recovery cycle and my other half had a hot shower and water from all sinks in the house was also hot. I’m assuming that the tank isn’t “sensing” it needs to heat until it is forced into recovery by use of water?
    – Thamil
    Commented Oct 16, 2018 at 13:20
  • If she used the same shower as you and had hot water after you had a lukewarm shower and then cycled* the thermostat on the tank, then this indicates that the thermostat is defective and the gas valve w/ thermostat must be changed. If you want to document the behavior more exhaustively keep documenting the behavior, and notify the company that sold you the heater exactly how it is failing to perform properly. *Does "cycled" mean turning the temp knob to high enough setting to make the burner light or to the max temperature, then back to 150 F after the main burner lights? Commented Oct 16, 2018 at 16:25
  • Which kind of gas valve does this heater have--the new digital one or the older analog one? youtube.com/watch?v=km3BtB1pjFM Commented Oct 16, 2018 at 16:40
  • Thanks for the feedback - yes the second shower was in the same shower. Yes, “cycling” means tuning the thermostat to hot to get it to ignite and then back to 150. It is an anolog not digital thermostat.
    – Thamil
    Commented Oct 16, 2018 at 18:31

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