PUMP PRESSURE
ADJUSTMENT (USING
EXTERNAL GAUGE)
1. Remove pressure gauge plug from filter
end cover (see Figure 11).
2. Install 0-15 PSI pressure gauge.
3. Start heater (see Operation, page 7). Al-
low heater to reach operating temperature
(approx. 10 minutes).
4. Set heater to MANUAL MODE, SETTING
5. This is the only setting that will allow
pressure adjustment.
5. Adjust pressure. Turn relief valve to right
to increase pressure. Turn relief valve to
left to decrease pressure. See specifica-
tions with Figure 12 for correct pressure
for each model. DO NOT OVERTIGHTEN
ADJUSTMENT SCREW. Service pump if
pressure can not be adjusted to proper
setting (see Figure 12).
6. Remove pressure gauge. Replace pres-
sure gauge plug in filter end cover.
Pressure
Gauge
Plug
Figure 11 - Pressure Gauge Plug
Removal
Pump
Model Pressure
110 6.9 PSI
160 6.7 PSI
175 6.8 PSI
220 8.4 PSI
Figure 12 - Adjusting Pump Pressure
Using External Gauge
PUMP PRESSURE ADJUSTMENT
(USING BUILT-IN GAUGE)
1. This heater continuously monitors pump
pressure with a built-in pressure sensor.
2. When the heater starts, pump pressure
will be displayed for 6 seconds.
3. To display the pump pressure while oper-
ating, operate the heater for 2 minutes, set
14
SERVICE PROCEDURES
Relief
Valve
Pressure
Gauge
www.usaprocom.com
the heater to MANUAL MODE, SETTING
5, then press the MODE/RESET button
once. Pump pressure will be displayed
(example: "6.9") for 5 seconds.
4. Adjust pressure. Turn relief valve to right
to increase pressure. Turn relief valve to
left to decrease pressure. See specifica-
tions with Figure 12 for correct pressure
for each model. DO NOT OVERTIGHTEN
ADJUSTMENT SCREW. Service pump if
pressure can not be adjusted to proper
setting (see Figure 12).
Relief Valve
Figure 13 - Adjusting Pump Pressure
Using Built-In Gauge
FUEL FILTER
1. Remove side cover screws using 5/16"
nut-driver.
2. Remove side cover with a 5/16" nut driver.
On 160, 175 and 220 models, remove two
wheel support bolts and nuts with a Phillips
screwdriver and an adjustable wrench.
Side
Cover
Upper Fuel Line
Figure 14 - Fuel Filter Removal
LED Display
Fuel Filter,
Bushing,
and Lower
Fuel Line
160108-01C