DeWalt DXH135HD, Instruction Manual

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Diagnostic Safety Shutdown and Trouble Shooting
These instructions are applicable for DXH135HD, DXH190HD, DXH215HD
SYMPTOM TROUBLE SHOOTING
High limit switch Open Circuit 1) Make sure heater is cooled off, toggle switch to “O” position, wait 5 minutes and retry.
Sparks, calling for flame, but 1) Check wiring to motor (per wiring schematic in manual).
no or slow motor operation 2) Make sure that the pressure gauge plug 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.
No Spark 1) Check length and gage of extension cord for proper amp. draw. (Check requirements on page 5.)
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.
Abnormal Motor Operation - 1) Motor speed too low (Motor should operate at 3450rpm, except 50K at 1550rpms) - Replace motor.
Motor overheats or Stops 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.
Unable to Detect Flame 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.
Flame Control Failure 1) Check wiring in heater (per wiring schematic in manual).
2) Replace oil flame control assembly.