Several days ago I discovered that my Pentair MasterTemp 400 heater shut off before reaching the set temperature. This was the case in both the general filtration mode & the spa mode. Having had this issue before, I discovered that the thermal regulator was corroded & would not open. So I installed a new regulator. Unfortunately, it did not solve the problem. There was no error code on the LCD screen & the Service Heater light was NOT illuminated. Looking at the rear of the circuit board, none of the LEDs were lit (except LED9 was dimly lit a green color).
Next I tested the thermistor by removing the 2 wires & connecting a resistor between them. The heater still would not fire. Finally I cleaned all of the electrical contacts. I even removed the circuit board (which had bit of corrosion) & gently cleaned it with electrical contact cleaner & a soft brush. After I reconnected everything, still the heater would not fire. However, the Service Heater light was on; but no error code. On the back of the circuit board, LED11 was lit (which I assume is associated with the Service Heater light).
So, at this point I am at a loss what to do next. With no LEDs illuminated, I'm starting to get suspicious that the circuit board itself might need to be replaced.
If anyone can offer me some guidance, I would truly appreciate it. Thank you so much.
Kit
Next I tested the thermistor by removing the 2 wires & connecting a resistor between them. The heater still would not fire. Finally I cleaned all of the electrical contacts. I even removed the circuit board (which had bit of corrosion) & gently cleaned it with electrical contact cleaner & a soft brush. After I reconnected everything, still the heater would not fire. However, the Service Heater light was on; but no error code. On the back of the circuit board, LED11 was lit (which I assume is associated with the Service Heater light).
So, at this point I am at a loss what to do next. With no LEDs illuminated, I'm starting to get suspicious that the circuit board itself might need to be replaced.
If anyone can offer me some guidance, I would truly appreciate it. Thank you so much.
Kit