Line Voltage And High Limit Eco Testing - Bradford White M-2-50T6DS Service Manual

Line Voltage Testing
1. Turn "OFF" power to water heater.
2. Remove access cover(s) from front of water
heater. Remove insulation and plastic cover
from thermostat.
3. Set multi-meter to volts AC.
4. Turn power "ON" to water heater.
5. Check voltage across terminals L1 & L3
of upper thermostat (see illustration 2).
A) Rated voltage IS present, power to the water
heater is okay.
B) Rated voltage NOT present, Check circuit breaker
at service panel.
High Limit (ECO) Testing
1. Check voltage across terminals L1 & L4 upper thermostat (see illustration 3).
A) Rated Voltage IS present, ECO is okay.
B) Rated voltage NOT present, proceed to step 2.
2. Turn power "OFF" to water heater and firmly press ECO reset button on thermostat(s). Turn power "ON" and recheck
voltage across terminals L1 & L4 of upper thermostat
(see illustration 3).
A) Rated voltage IS present, the ECO has opened indicating the water in the tank is or has over heater.
Check the following:
1. Thermostat must be in full contact with tank.
2. Be sure heating element(s) is not shorted to ground (see page 15).
3. Proper thermostat operation (see procedures beginning on page 16).
B) Rated voltage NOT present, water in tank may be over heated.
1. If water is hot, turn "OFF" power to water heater and flow water through tank to cool below set point
of upper thermostat. Recheck voltage per step 1.
2. If water is cool, Replace upper thermostat.
14
SERVICE PROCEDURE RE-I
Line Voltage & High Limit (ECO)
High voltage exposure. Use caution when
making voltage checks to avoid personal injury.
Illustration 2
Page 14
Testing
WARNING
ECO reset
button
Illustration 3