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Thread: Pentair MasterTemp 400 won't shut off

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    Pentair MasterTemp 400 won't shut off

    I turned on my pool heater today to heat up the pool and when I went to shut it off it would't. None of the buttons are functioning but the heater is still working. The LED is still functioning as the temp shows and changes as the pool heats up. All the buttons feel fine. The only way it will shut off is when the pump is off. And I can't switch from pool to spa so I can't heat the spa over the temperature I set for the pool which was 80. Please help, I can't find any topics online for this.
    30K gallon IG
    Pentair MasterTemp 400

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    Re: Pentair MasterTemp 400 won't shut off

    Sounds like the keypad membrane is bad. Replace it and hopefully it will be fine. Only other part could be the control board under the keypad. You don't have the heater on a seperate breaker?
    Paul
    http://www.gastekservices.com A word of caution: When working with gas and electrical you might want to consider a licensed contractor. Consider the value of your life and others around you. If you would like to provide a review of the help I provided, please use the following link to leave a review. gastek - Google Search,

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    Re: Pentair MasterTemp 400 won't shut off

    We are hoping it is just the membrane. It doesn't have a separate breaker, we think it is wired into the same breaker as the pump. The membrane was peeled up a little, my husband peeled it off and looked at the buttons, all but one seem ok but one definitely doesn't feel right. We are worried that moisture got in where the control board is but I would think that would short out the whole thing. Everything still totally functions including the LED, it is just stuck in the last setting I put it on. The heater fires, the temperature is reading accurately and the heater is shutting itself off properly when it hits the set temperature.
    30K gallon IG
    Pentair MasterTemp 400

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    Re: Pentair MasterTemp 400 won't shut off

    Sounds like the board is probably good since the unit fires, gets to temp and then shuts off.
    Paul
    http://www.gastekservices.com A word of caution: When working with gas and electrical you might want to consider a licensed contractor. Consider the value of your life and others around you. If you would like to provide a review of the help I provided, please use the following link to leave a review. gastek - Google Search,

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    Re: Pentair MasterTemp 400 won't shut off

    Cross your fingers for me, just ordered the membrane....a MUCH cheaper fix then the board. Thanks for the reply, this is our first time having pool.
    30K gallon IG
    Pentair MasterTemp 400

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