Lennox International Inc. AIR HANDLERS Water Heater User Manual


 
Page 20
505047 09/06
WARNING
WARNING TO SERVICE PERSONS! Electric shock hazard. When electrical power to the internal
control box components must be available for troubleshooting, a common practice is to
construct a by−pass" of the door interlock switch. When such a by−pass is in place, a potential
shock hazard is present which can cause injury or death. Make sure any door interlock switch
by−pass has been removed after troubleshooting is complete and BEFORE attempting any re-
pairs to the control box components!
Troubleshooting: Heating Sequence of Operation
NO
Check for 24 Volts Between
W and C at A52 Terminal Strip
CONDITIONS:
Power On
Normal Operation LED: Steady Flash
Fixed blower−ON delay (45−second) complete
Blower Operates at the Heating Speed Selected by
HEAT Jumper and ADJUST Jumper Positions on
the BDC3 Control (A52)
YES
CFM Light on A52 Indicates Blower
Speed Selection with 100CFM / Blink
YES
Thermostat (S1) Demand Satisfied
YES
30 Second Blower Off Delay (Fixed) Complete
Thermostat (S1) Calls for Heat
Demand for Heat Satisfied
Check for 24 Volts Between Pins 3 and 2 on J49
YES
YES
NO