DeWalt DXH12B Instruction Manual page 8

MAINTENANCE CLEANING AND INSPECTION PROCEDURE
1. Allow heater to thoroughly cool before performing any maintenance.
2. Remove disposable 1 lb. cylinder from heater or turn OFF gas supply at remote cylinder
valve, and disconnect hose from heater.
3. Remove (4) four screws that secure the rear cover to the Heater.
4. Pivot cover outward from bottom. Release from 2 top clips. Set aside.
5. Remove (4) four burner retaining screws and fuel line from burner assembly.
6. Remove burner assembly from back of housing.
7. Inspect interior of housing for accumulation of dust, insect or spider webs. If necessary,
clean interior housing with a vacuum cleaner or apply air pressure. Do not damage any
components within the housing assembly when you are cleaning.
8. Inspect and clean main burner orifice (threaded into orifice holder). Orifice holder is
attached to the burner assembly venturi with (2) two screws.
9. Inspect and clean pilot (mounted to bracket) by using a vacuum or apply air pressure
through the holes in the pilot indicated by the arrows in Figure 8.
WARNING: Never use needles, wires, or similar cylindrical objects to clean the pilot
to avoid damaging the calibrated orifice that controls the gas flow assembly.
10. Apply air pressure (max. 30 psi) into ceramic tile of burner assembly and the venture
tube to remove dust, lint or spider webs.
11. Reassemble main burner orifice holder
onto the burner.
12. Reinstall burner assembly into the heater
housing.
13. Reinstall fuel line and check for leaks.
14. Install heater back cover.
STORAGE
• 1 Lb. Propane cylinder(s) must be
disconnected from heater when not in
use.
• Indoor storage of the heater is permissible only if the cylinder is disconnected
and removed from the heater. Cylinders must be stored outdoors out of the
reach of children and must not be stored in a building, garage or any other
enclosed area.
• If a 20 Lb. Propane cylinder is not disconnected from the heater, the heater
and the cylinder must be stored outdoors, in a well ventilated space, out of
reach of children, and must not be stored in a building, garage or any other
enclosed area.
Pilot Flame
Oxygen Depletion
Sensor
Figure 8
TROUBLESHOOTING
IF SPARK ELECTRODE DOES NOT PRODUCE SPARK
CHECK
• Spark electrode broken - replace ODS (Oxygen Depletion Sensor)
• Igniter wire may not be attached to spark electrode
• Igniter wire damaged - replace
• Pulse Igniter Battery dead - replace AA battery
IF SPARK ELECTRODE PRODUCES SPARK BUT PILOT DOES NOT LIGHT.
CHECK
• No gas to heater - install disposable cylinder or connect hose and filter where
required and turn on valve at remote cylinder.
• "PILOT" position not properly aligned - turn gas control knob to "PILOT" position and
depress.
• Pilot is blocked from spider web or dirt - clean pilot (See MAINTENANCE beginning
on page 7.)
IF PILOT FLAME DOES NOT STAY LIT WHEN KNOB IS RELEASED
CHECK
• Control knob in "PILOT" position not completely depressed or held in long enough to
purge air from lines.
• Pilot flame not surrounding thermocouple - clean pilot (See MAINTENANCE
beginning on page 7.)
• Pilot Assembly defective - replace
• Tip switch wires disconnected - connect
IF MAIN BURNER DOES NOT IGNITE
CHECK
• Main burner orifice is blocked - clean burner (See MAINTENANCE beginning on page
7.)
IF HEATER KEEPS SHUTTING "OFF" DURING NORMAL OPERATION
CHECK
• Pilot is blocked - clean pilot (See MAINTENANCE beginning on page 7.)
• Provide minimum fresh air opening of 9 square inches (example, 3" x 3" opening)
• Tip over switch activated from bumping heater. Re-light.
• Regulator defective - Replace regulator.
• Internal contamination - Replace control valve and regulator
• Call Technical Services for additional information.
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