electrical
customer complains unit isn't working at all.
You find 120 volt power but no 24 volt
what part has most likely failed
The transformer
units blower motor has high amperage draw, static pressure is .8 inwc, unit says its max is .7 inwc.
The duct work is proper, and evaporator coil is clean, you find the return side has the highest of the two for static pressure
what should I do next
Check Return Grill
The furnace is going out on high heat
The blowers amperage is high
The air supply is slightly weak
what's my problem
Air restriction
customer complains unit is not responding at all
you find unit has 120 and 24 volt power. you find out you can jump wires to make unit work
What part most likely has failed
thermostat
unit is making a horrible loud noise. This is only when the blower is on. The unit shakes aggressively
What should I do next (two things)
Check The squirrel cage of the blower to make sure nothing is on it and check bearings of motor
Burnt wires on high volts side
breaker is tripped
Whats my problem
grounded out high volt hot wire
Customer complains that they have had 3 companies out and none have found the problem
you notice that the unit runs perfectly fine for the first 2 start ups but on the 3rd you notice the blower motor shuts off before inducer motor and flame
what part has most likely failed
The control board
The unit has been shutting off after running for only 5 or so minutes
The flame is blue with orange tip, nothing changes when the blower comes on. after running for 5 minutes the unit shuts off.
what should I do next
OHM across or check volt for high temp limit switch
motor only spins sometimes
makes weird noise
motor has low and high voltage
what's my problem
The bearings
customer complains that unit would try to run but now wont.
you find unit is in a hard lock out, you reset power
the unit turns on the inducer motor but nothing after. the inducer motor gives off .9 inwc
the pressure switch calls for .5 inwc
what part most likely has failed
the pressure switch
Unit is in hard lock out. you find the flame rolls back when unit comes on unit confirming cracked heat exchanger
what do I do next
LOCK OUT TAG OUT!!!
nothing hooked to either plenum
customer left basement door unlocked
what's my problem
someone stole it
customer says unit is not blowing any air
you find that the blower motor has 120 volt power and 24 volt call. the motor is a PSC motor the motor its self is fine
what part most likely has failed
Unit isn't working at all
you find that 3amp fuse on board is popped. you put a resettable fuse
what should I do next
unit has soot everywhere
the burners are warped
what's my problem
too much gas pressure let through gas valve