Pool Heater Wiring Issue

[thepoolman1]

Did the pilot auto light or did you have to light it manually? If you lit it, you have a millivolt heater with a standing pilot. No transformer, no electronic ignition, no line voltage to the heater.

DO NOT dry-fire any heater, especially a 400K unit. Even a second or two can cause damage and perhaps personal injury.

[huskyrider]

I'd say it's a millivolt style heater, the wires he described lead to the firemans safety switch.
It could be one of several things
Pressure switch, gas valve, thermocouple and/or its lead wires would be good items to begin with.

See Ya,
Kelly