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Thread: Minimax NT won't stay lit

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    Minimax NT won't stay lit

    My 8 year old Minimax NT Lo Nox heater was dead. Checking voltages, I figured out that the transformer went bad. I replaced the transformer and now get power to the Digital Display Temperature Controller (DDTC). But now I get an E05 (ignition failure) message.

    There are 4 LEDs in the back of the DDTC. The HiTemp, Tfuse, and Fan LEDS are lit. the PV LED is not lit. When the heater is turned on and it goes through startup sequence, the fan blows, the igniter gets red (can't see it directly, but can see the reflection in one of the burners), gas turns on, burners ignite and light for about a second, then turn off while the fan continues. Occasionally, when the burners light it will be somewhat explosive and flame will shoot out past the orifices. Most of the time, the burner light normally though.

    I took out the burners and checked the orifices and cleaned everything up, but they weren't too dirty. This didn't help. I checked the resistance of the igniter/flame sensor and read 55 ohms cold. I took the wires off of the igniter/flame sensor and connected my voltmeter to them. There was low voltage during the first part of the startup sequence, and then it increased, but only to about 90 volts. My source is 240 volts.

    Any chance this is the igniter/flame sensor gone bad? How can I check the flame sensor? It seems as though the igniter portion of the igniter works since the burners light. I'm hoping it's not the ignition control module, but 90 volts seems wrong. Then again, I'm not sure my test is valid since I removed the wires from the igniter/flame sensor.

    Any thoughts are appreciated.

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    Join Date
    May 2010
    Yuma AZ

    Re: Minimax NT won't stay lit

    I'm currently having issues with my Mastertemp not staying lit. You should give Pentair customer service a call. They are very helpful and will talk you through some troubleshooting directions over the phone. Wait time for me was about 10 minutes and the technician was very helpful.
    Good luck,

    Pentair customer support 800-831-7133
    10,000 gallons IG Freeform, 8ft raised spa,pebble finish
    FNS 60 Sqft DE Filter,2HP Whisperflow for Pool/Spa filtering
    2HP Whisperflow for Spa jets
    1HP Whisperflow for Waterfall
    Master Temp 400,000 Btu Heater

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