28
Midco International Inc.
8471 95
Part 2 Service - Trouble Shooting for 24V Burners
For 24V Burners:
TROUBLE CHART
Make sure the thermostat and operating controls are calling for heat.
CAUTION
: If a test indicates an electrical component may be defective, before replacing
it, make sure that its associated wiring is not at fault.
ELECTRICAL AND FLAME CHECKS MUST BE MADE IN THE ORDER LISTED BELOW.
A. MOTOR WILL NOT RUN
1.
Con
fi
rm 120V between strip terminals L1 and L2 and verify the circuit polarity and
electrical ground between strip terminal L1 and burner Ground.
2. Check for 120V between strip terminals L1 and L2.
a. No voltage, open circuit in operating controls.
b. Voltage present, motor is defective.
B. MOTOR RUNS CONTINUOUSLY, PILOT WILL NOT LIGHT
1.
Con
fi
rm that ALL Main Manual Shut-O
ff
Valves are open.
2. After the pre-purge, if the pilot
fl
ame is not proven within the pilot
fl
ame establishing
period, or if the proof of
fl
ame is lost during the burner run and the pilot is not re-established
after the pre-purge, the Ignition Control Module will lock out. RESET the 24 volt ignition Control
Module by setting the operating control to OFF or the thermostat below room temperature for at
least 30 seconds.
3. Clogged pilot ori
fi
ce.
4. Pilot regulator mis-adjusted or defective.
5. Defective spark electrode, Ignition Control Module or Transformer for 120V.
6. Defective spark wire.
7. Wrong pilot ori
fi
ce.
8. Defective pilot valve.
9. Defective blower air switch.
10. Step down transformer is defective, (if applicable).
11.
Insu
ffi
cient pilot
fl
ame sensing signal.
C. PILOT LIGHTS, NO MAIN FLAME
1.
Poor
pilot
fl
ame adjustment.
2.
Defective
fl
ame sensing rod or wire.
3. Flame sensing rod mis-located.
4. Pilot regulator defective.
5. Defective Ignition Control Module.
6. Defective main gas valve.
7. Low gas pressure.
8. Grossly mis-adjusted main gas and air mixture.
9
.
Insu
ffi
cient pilot
fl
ame sensing signal.
__________________________________________
XVII Trouble Chart
for 24V Burners
!
A Motor Will
Not Run or Motor
Runs in Repeated
Cycles
B Motor Runs
Continuously,
But no Flame
C Pilot Lights,
No Main Flame
