Power Switch Module (Psm) Testing - Bradford White ERE240 Service Manual

SERVICE PROCEDURE
PSM Testing

Power Switch Module (PSM) Testing

1. Turn all power to the water heater "OFF"
2. Remove lower access cover and insulation from inside the hand hole.
3. Disconnect the wires at the three screw terminals
4. Set the multi-meter to the Ohms (Ω) setting.
5. Check resistance between terminals 1 and 2 (Figure 6), as well as terminals 1 and 3 (Figure 7) on the Power Switch
Module. This should read somewhere between 25MΩ-150MΩ depending on the quality of multimeter used.
a. If the resistances fall within the specified range and are approximately equal between the two measurements
the Power Switch Module is functioning properly.
b. If one or both of the measurements are out of that range, or they are significantly different (i.e one
measurement reads 50MΩ and the other reads 80MΩ) then the power switch should be replaced.
16
High voltage exposure. Be sure power is
"OFF" when performing this procedure.
Figure 6
Figure 7
16
WARNING