Rheem P-M406 Operating Instructions - Page 46

CONTROL LOGIC - FLOW CHART Power On Is the water temperature displayed? NO YES Push MODE switch to select "Pool" or "Spa" Push Temp arrow to scroll to desired temperature Water temperature and set NO temperature displayed? YES "Heating" will display briefly "Spark" Flame icon displayed and flashing? OR Water temp displayed? (pilot lit and rectified) NO YES • Check On/Off switch (under lid on control panel) • Check for 120/240 volts to the transformer (time clock, circuit breaker, wire connections) • Check for 24 volts to Circuit Board (P6 connector) "Remote" and Water Temperature displayed (a remote control is controlling the heater) Note: Disconnect the remote by turning the remote function off. See page 36 for instructions. NO Is a fault code displayed and flashing? YES Diagnostic Readouts "Sensor Failure," "Sensor Open" or "Sensor Short" Temperature sensor out of range (replace sensor) Sensor Failure Inspect thermister, wires, and connector at Terminal P1 Check resistance value of the thermister. Reference to chart below. Replace thermister if not within 10% of values shown below. If okay, replace Circuit Board. Sensor resistance at various temperatures Temp Degrees F 40 50 60 70 80 90 100 106 Resistance (k) 261.1 199.0 153.1 118.8 93.0 73.3 58.3 51.0 If okay, replace Circuit Board "Water Sw Open" "Hi Limit 1 Fault" "Hi Limit 2 Fault" "Rollout Sw Open" "Clock/Fireman Sw" "Vent/Field Sw #1" Pressure switch. Verify water flow and pressure CLEAN FILTER / STRAINER - backwash if neccessary. High limit switch. Verify water flow. Inspect internal Thermostat (Unitherm Governor) and bypass valve. Rollout Sensor - Check for blocked heat exchanger and soot. Atmospheric Units - Replace fusible link. Lo NOx Units - Press manual reset button. Fireman or Remote switch connected to safety loop is in the OFF mode. Vent switch open. Check connections to the board. If extractor installed, troubleshoot extractor. "Ignition Lockout" "Ignition Failure" Ignition lockout. Check power at pilot valve. Check spark (bad ignition circuit or hi-tension wire). Verify clean pilot orifice and clearance from igniter to ground hood. Ignition failure. Verify gas to the heater. Verify valve operation (gas present at tube fitting). Heater Fired? YES END NO Verify power at MV on P-4 Terminal on digital circuit board. Verify power to valve MV voltage. (Replace valve.) 46