Service Procedures; Upper Shell Removal; Spark Plug - Desa SB350D Owner's Manual

HIGH PRESSURE PORTABLE FORCED AIR
HEATER 350,000 AND 600,000 BTU/HR
SERVICE
PROCEDURES
WARNING: Never service
heater while it is plugged in, op-
erating, or hot. Severe burns and
electrical shock can occur. Only
a qualified service person should
service and repair heater.

Upper Shell Removal

1. Remove screws along each side and top
of heater using 5/16" nut-driver. These
screws attach upper and lower shells
together (see Figure 5).
2. Lift upper shell off.
Figure 5 - Upper Shell Removal, 600,000
Btu/Hr Model
Fan Blades and Air Deflectors
1. Remove upper shell (see column 1).
2. Clean fan blades and air deflectors with
clean, soft cloth moistened with kero-
sene or solvent (see Figure 6).
3. Dry fan blades and air deflectors thor-
oughly.
4. Replace upper shell.
Air Deflector
Upper Shell
Figure 6 - Fan Blades and Air Deflectors

Spark Plug

1. Remove upper shell (see column 1).
2. Remove spark plug wire from spark
plug (see Figure 7).
3. Remove spark plug from burner head
using 13/16"
open-end wrench (see Figure 7).
4. Replace spark plug if damaged or
heavily coated with carbon.
5. Clean and regap spark plug electrodes
to .075 inch (see Figure 8).
6. Install spark plug in burner head.
7. Attach spark plug wire to spark plug.
8. Replace upper shell.
Burner Head
Figure 7 - Spark Plug Removal
Figure 8 - Spark Plug Gap
Nozzle
1.
2.
3.
4.
5.
6.
7.
8.
9.
Fan Blade
10. Replace nozzle into burner head and
11. Attach burner head to combustion
12. Install spark plug in burner head.
13. Attach spark plug wire to spark plug.
14. Attach fuel line to solenoid valve.
15. Replace upper shell.
Nozzle
Burner
Spark Plug Head
Figure 9 - Replacing Nozzle
Spark
Plug Wire
.075
inch
10
Remove upper shell (see column 1).
Remove fuel line from solenoid valve
using 7/16" wrench.
Remove spark plug wire from spark
plug.
Remove spark plug from burner head
using 13/16" open-end wrench.
Remove five screws using
5/16" nut-driver and remove burner
head from combustion chamber.
Place burner head into vise and lightly
tighten.
Carefully remove nozzle from burner
head using 5/8" socket wrench (see Fig-
ure 9).
Inspect nozzle for damage. If damaged
or clogged, replace nozzle.
Make sure plug is in place on burner
head.
tighten firmly (175-200 inch-pounds).
chamber.
Tighten firmly.
Spark
Plug
Plug
Solenoid
Fuel
Valve
Line
Spark
Plug
Wire
106029