650. Support: Baptistry or Baptismal Heater Unit Heater ON light is not activating.

You have reported that the heater unit is not activating the heater, and the heater ON light does not come on. 1) Verify to make sure correct power is supplied to the heater unit. 2) Make sure the pump is discharging water through the heater with strong water flow. A pressure switch is installed on this heater unit, therefore the pump much apply pressure through the heater. If the pump is sucking water from the heater, it will not work. 3) Baptistry tubs or pools normally don't have jets installed, and the output pipe is an open flow with minimal pressure. If there are no jets installed and there is only an open flow on the output line, make sure to install a ball valve on the output side of the heater (within the return line). Then adjust the ball valve slightly to the position that will allow the heater ON light to turn on (water temp must be below 104 degrees with the thermostat turned to max). This is to increase water pressure in the pipe that will activate the pressure switch on the heater unit. Do not adjust the ball valve completely. This will stop water flow and can damage the pump and heater unit. A reducer can be installed on the end of the pipe (a trial and error is required to determine the correct size reducer). Or an elbow fitting can be installed on the return pipe (within 6 inches from the heater). 4) It is possible that the heater ON light is not working but the heater is heating. Make sure to allow the pump and heater unit to run for at least 1 hour to determine if there is a heat rise (within 5-8 degrees for 220V). An electrician can also verify voltage across the heater terminals. If there is strong water pressure from the pump, the pump is discharging water from the heater, and there is at least 1.5 PSI pressure towards the pressure switch, the problem may be the pressure switch or the heater circuit. Request an RMA to authrorize the return of the heater unit for inspection.