Pentair Pool Products MiniMax NT Series Service Manual page 32

Troubleshooting
1. Check water temperature, if water has reached the desired temperature, the thermostat will cut
off power to the module and the heater will stop firing. In this case the POWER Light would
remain ON.
2. Check the voltage on the Secondary side of the Transformer. It should be greater than 24 VAC.
If the voltage is less than required, the incoming voltage may be too low for the heater to operate
properly, there could be a wiring short or the wrong voltage connector may be connected to the
White Male Connector. Because the Power light is not a specific 24 VAC light, it will illuminate
with less than 24 VAC, so even if the Power Light is ON, the voltage may not be correct.
3. The Pool/Spa switch may have inadvertently been switched Off. Even though the Pool/Spa
switch does not have to be ON for the POWER Light to be ON, it does have to be pushed to
either the Pool or Spa position in order to transfer voltage to the rest of the controls.
4. Make sure that the Thermostat Knobs have been turned to Hot because the voltage must pass
through the thermostat (potentiometer) first before going to any other control. If the
potentiometer or thermistor is not working or is disconnected from the Control Board, only the
POWER Light will be ON. If you suspect that this may be the problem, first check the
thermistor connections on the back of the Control Board. If this does not light the T-STAT Light,
connect a known functional thermistor to the Control Board. If the light still does not come on,
the Control Board is bad.
Figure 26.
P/N NTSM03
DIAGNOSTIC LIGHTS SHOW
"POWER" ONLY!
32
Rev. B 2-11-04