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  1. #1
    Join Date
    Jan 2011
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    Shut off switch on HTP tank

    I have a newer HTP indirect water tank. There is a switch installed that is supposed to turn off the call for heat, it's basically a thermostat wire with an on/off switch. However even when the switch is off, the tank keep heating the water. One end of the wire goes into the panel on the tank, the other end goes into the TACO box on the wall. If I flip the switch on, I do see a zone activate and I can hear something happening in the tank. But - even after a week with the switch clearly off and then 7+ showers later the water was still very hot and the H pipe on top is also very hot (too hot to hold for more than a second).

    ANy ideas on why the switch would not work? Maybe it's not wired correctly into the tank and the tank defaults to calling for heat?

    I know I can just turn down the dial on top, but this is a seasonal house and I wanted to convert that manual switch to a smart switch so I can turn the water on and off remotely before and after short term renters arrive.

    Thanks in advance!

  2. #2
    Join Date
    Jan 2012
    Broomall, PA
    Post Likes
    Sounds to me like a few possibilities or a combination of:
    -A thermostat wire from the aquastat on the indirect to the Taco zone control is shorted or pinched, calling the indirect.
    -The aquastat on the indirect is defective (least likely but possible)
    -The zone control is defective, easily checked by a qualified tech.
    -Either a flow check is missing, the indirect is piped incorrectly (not trapped), or if it's controlled by a zone valve or circulator, that needs to be checked also.
    This is easy troubleshooting with the right knowledge and a meter by a qualified tech.
    Uh...Google it yourself!

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