Service Procedures - Desa H.S.I. Series Owner's Manual

SERVICE
PROCEDURES
WARNING: Never service
heater while it is plugged in, op-
erating, or hot. Severe burns and
electrical shock can occur.
UPPER SHELL REMOVAL
1. Remove screws along each side of
heater using 5/16" nut-driver. These
screws attach upper and lower shells
together.
2. Lift upper shell off.
3. Remove fan guard.
Upper Shell
Figure 5- Upper Shell Removal
FAN
IMPORTANT: Remove fan from motor
shaft before removing motor from heater.
The weight of the motor resting on the fan
could damage the fan pitch.
1. Remove upper shell (see above).
2. Use 1/8" Allen wrench to loosen set-
screw which holds fan to motor shaft.
3. Slip fan off motor shaft.
4. Clean fan using soft cloth moistened
with kerosene or solvent.
5. Dry fan thoroughly.
6. Replace fan on motor shaft. Place fan
hub flush with end of motor shaft (see
Figure 6).
7. Place setscrew on flat of shaft. Tighten
setscrew firmly (40-50 inch-pounds).
8. Replace fan guard and upper shell.
104655
Fan
Motor
Motor
Shaft
Setscrew
Figure 6 - Fan Cross Section
AIR OUTPUT, AIR INTAKE,
Fan
AND LINT FILTERS
Guard
1. Remove upper shell (see Upper Shell
Removal).
2. Remove filter end cover screws using
5/16" nut-driver.
3. Remove filter end cover.
4. Replace air output and lint filters.
5. Wash or replace air intake filter (see
Preventative Maintenance Schedule,
page 5).
6. Replace filter end cover.
7. Replace fan guard and upper shell.
IMPORTANT: Do not oil filters.
Air Intake Filter
Lint Filter
Air Output Filter
Figure 7 - Air Output, Air Intake, and Lint
Filters

• SERVICE PROCEDURES

PUMP PRESSURE
ADJUSTMENT
1.
2.
3.
Flush
4.
5.
6.
Figure 8 - Pressure Gauge Plug Removal
Filter End Cover
Fan Guard
Figure 9 - Adjusting Pump Pressure
7 For more information, visit www.desatech.com
Remove pressure gauge plug from filter
end cover.
Install accessory pressure gauge (part
number HA1180).
Start heater (see Operation, pages 4 and
5). Allow motor to reach full speed.
Using a flat blade screwdriver, adjust
pressure. Turn relief valve to right to
increase the pressure. Turn relief valve
to left to decrease the pressure. Set pump
pressure at 5.3 for 110,000 and 115,000
Btu/Hr models, 5.4 PSI for 150,000 and
155,000 Btu/Hr models, and 5.6 PSI for
165,000 Btu/Hr models.
Stop heater (see Operation, pages 4
and 5).
Remove pressure gauge. Replace pres-
sure gauge plug in filter end cover.
Relief
Valve
Pressure
Gauge
Plug
Pressure
Gauge
Continued