I started having a random, erratic problem with my 2yr old Pentair Mastertemp 400 natural gas heater in October. Using either the EasyTouch keypad, or my Pentair ScreenLogic app on my iPhone, I turn the spa on... give it a minute or two, then turn on the heater.
I check the back of the control board in the heater and the LED7 light is on, which is right next to thermistor plug... so, it seems to be a bad thermistor. I replaced the thermistor today and it did the same thing.
For the fun of it, I unplugged the connector to the thermistor from the board and tried firing it up... it did the same thing, even with the thermistor not plugged in.
Thoughts?
- System goes into Spa mode
- PENTAIR MASTERTEMP 400 turns on
- Goes through the standard boot up procedure (128/R13 appear on the LCD of heater)
- Then the display shows "1"
- The heater fires up and starts heating for about 3-4 minutes
- Then it errors out with E01... and keeps the code on for a long while.
I check the back of the control board in the heater and the LED7 light is on, which is right next to thermistor plug... so, it seems to be a bad thermistor. I replaced the thermistor today and it did the same thing.
For the fun of it, I unplugged the connector to the thermistor from the board and tried firing it up... it did the same thing, even with the thermistor not plugged in.
Thoughts?