Trouble Shooting - Mr. Heater 50KR Operating Instructions And Owner's Manual

DIAGNOSTIC SAFETY SHuTDOWN AND TROuBlE SHOOTING
Model MH125KTR, MH175KTR and MH210KTR heaters are equipped with a diagnostic control board and flashing LED error indicator. This
flashing LED signals indicate unit operation status. See the following diagnostic guide for unit status and corrective action if necessary.
lED uNIT OpERATION
Steady ON System Check
Steady OFF Operation OK
2 Flashes No flame detected
3 Flashes High limit switch
failure
4 Flashes CAD Cell Failure
Power Light Power to control
Model MH50KR and MH75KTR heaters are NOT equipped with a diagnostic control board or flashing LED error indicator. See the following
troubleshooting guide for unit status and corrective action if necessary.
SYMpTOM
High limit switch Open Circuit
Sparks, calling for flame, but
no or slow motor operation
No Spark
Abnormal Motor Operation -
Motor overheats or Stops
Unable to Detect Flame
Flame Control Failure
Mr. Heater, Inc. | Kerosene Forced Air Heater

TROuBlE SHOOTING

System performing self test. No action required.
No action required.
Heater fails to start during the first 30 sec. of operation.
1. Check wiring to motor (per wiring schematic in manual).
2. Make sure that the pressure gauge is in place and not damaged.
3. Adjust pressure for proper heater operation per manual.
4. With heater disconnected from AC source, rotate fan clockwise to verify motor is free.
5. Remove air filter housing from motor and inspect the pump rotor for damage. If damaged, replace rotor assembly.
6. If wiring is correct, pump rotor is okay, and motor is not rotating freely, replace motor or power-pack assembly.
7. If problem persists, replace oil flame control assembly.
8. Check for spark arching from the electrode assembly (ref. 50), to the combustion cylinder (ref. 39).
9. Check the cad cell (ref. 38) for
1. Make sure heater is cooled off, press reset switch and retry.
1. Check wiring to cad cell (per wiring schematic in manual).
2. Clean cad cell photo cell.
• Slide cad cell out of cad cell holder.
• Push the photo cell out of the black rubber cad cell housing by pushing on the 2 purple wires.
• Clean the photo cell with a soft cloth and rubbing alcohol.
• Pull the photo cell back into the cad cell housing and reinstall into holder.
• Test heater.
3. If the heater still does not operate, replace cad cell.
4. Replace oil flame control assembly.
1. Sensing power. No action required.
TROuBlE SHOOTING
1) Make sure heater is cooled off, toggle switch to "OFF" position, wait 5 minutes and retry.
1) Check wiring to motor (per wiring schematic in manual).
2) Make sure that the pressure gauge is in place and not damaged.
3) Adjust pressure for proper heater operation per manual.
4) With heater disconnected from AC source, rotate fan clockwise to verify motor is free.
5) Remove air filter housing from motor and inspect the pump rotor for damage. If damaged, replace rotor assembly.
6) If wiring is correct, pump rotor is okay, and motor is not rotating freely, replace motor or power-pack assembly.
7) If problem persists, replace oil flame control assembly.
8) Check for spark arching from the electrode assembly, to the combustion cylinder.
9) Check the cad cell for continuity.
1) Check length and gage of extension cord for proper amp. draw. (Check requirements on page 4.)
2) Check wiring to igniter (per wiring schematic in manual).
3) Check gap between electrode probes (2.3 - 3 mm).
4) Still no spark, replace igniter assembly.
5) Replace oil flame control assembly.
1) Motor speed too low (Motor should operate at 3450rpm) - Replace motor.
2) With heater disconnected from AC source, rotate fan clockwise to verify motor is free.
3) Remove air filter housing from motor and inspect the pump rotor for damage. If damaged, replace rotor
assembly.
4) If wiring is correct, pump rotor is okay, and motor is not rotating freely, replace motor or power-pack assembly.
5) Replace oil flame control assembly.
1) Check wiring to cad cell (per wiring schematic in manual).
2) Clean cad cell photo cell.
a) Slide cad cell out of cad cell holder.
b) Push the photo cell out of the black rubber cad cell housing by pushing on the 2 purple wires.
c) Clean the photo cell with a soft cloth and rubbing alcohol.
d) Pull the photo cell back into the cad cell housing and reinstall into holder.
e) Test heater.
3) If the heater still does not operate, replace cad cell.
4) Replace oil flame control assembly.
1) Check wiring in heater (per wiring schematic in manual).
2) Replace oil flame control assembly.
continuity.
6
Operating Instructions and Owner's Manual