shower hot water not working, cold water only comes out?

I have a single handle shower valve. When i turn it to hot, only cold water comes out...at the same rate as when turned to cold. Hot water does work in the bathroom sink, as well as in the rest of the house. I have tried running the hot water in the sink at the same time as the shower, hoping it would "prime" it. No luck there. I cannot see a brand name on the shower valve, but I believe it to be 40 years old, I highly doubt it has been changed out since house was built in 72. It's never been a problem before, but admittedly it's been probably 2 years since it was used.

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    Since you only have this problem in one fixture, and since it once worked, you certainly need to rebuild or replace the mixer valve. I recommend a plumber for showers -- they're the trickiest in the house.

    Source(s): homebuilder
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  • 3 years ago

    Shower Hot Water Not Working

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  • paul h
    Lv 7
    7 years ago

    Some shower valves have an anti-scald feature which is adjustable to prevent scalding hot water from flowing out instead of mixing with cold if the cold side pressure drops like when flushing a toilet ....that anti-scald device may be stuck closed from scale deposits or the mixing valve has internal parts that are clogged or installed improperly. I've seen some newer single handle designs where the person installed them upside down which prevented the hot water side from opening fully. Would have to take the handle and trim plate off and remove stem and check for blockages or other issues....make sure any shutoff valve in the hot water line is not closed or partially open....it could also be clogged with sediments or scale.

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  • Truth
    Lv 7
    7 years ago

    sounds like you hot water heater has tripped it breaker and need to be reset or the element has gone bad and needs to be replaced. I have fix several.

    first check the breakers for any tripped. if not tripped turn off breaker for hot water heater make sure it the right one. then take find the hot water heater ..pull the small cover and press the red it was t reset button on the thermostat.. if it clicks it was tripped and you may have fix the issue .. if not it most likely the element ... in that can you will need to drain the tank and replace the element.. it is the round part looks like a nut with 2 screws in the middle with 2 wires collected. make notes when you pull so you can put back as you found when replaced. you can get the element and any tools needed and any hardware store.. cost about $30 for each element some larger hot water units carry two ..one high 1 low..

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