Sterling GF-400 User Manual

24

2.  Turn off the manual gas valve and electrical power to 

the unit heater.

3.  To clean or replace the burners, remove burner 

cover. Remove top strip from above burners. Lift 
burners up and pull away from manifold to remove.

4.  With the burners removed, wire brush the inside 

surfaces of the heat exchanger.

5.  Remove any dirt, dust, or other foreign matter from 

the burners using a wire brush and/or compressed 
air. 

6.  Reassemble the unit heater by replacing all parts in 

reverse order.

7.  Check the burner adjustment.
8.  Check all gas control valves and pipe connections for 

leaks.

9.  Check the operation of the automatic gas valve by 

lowering the setting of the thermostat, stopping the 
operation of the gas duct furnace. The gas valve 
should close tightly, completely extinguishing the 
fl ame on the burners.

10.  Inspect and service motor/fan assembly. To maintain 

efficient air flow, inspect and clean the fan blades 
and guard to prevent buildup of foreign matter.

11.  Check lubrication instructions on motor. If oiling is 

required, add 3 or 4 drops of electric motor oil as 
follows:
a.  Light Duty - After 3 years or 25,000 hours of 

operation.

b.  Average Duty - Annually after 3 years or 8,000 

hours of operation.

c.  Heavy Duty - Annually after 1 year or at least 

1500 hours of operation.

12.  Check and test the operational functions of all safety 

devices supplied with your unit.

All Maintenance/Service information should be recorded 
accordingly on the Inspection Sheet provided in this 
manual.

To check gas tightness of the safety shut-off valves, 
turn off the manual valve upstream of the appliance 
combination control. Remove the 1/8 inch pipe plug on 
the inlet side of the combination control and connect 
a manometer to that tapping. Turn the manual valve 
on to apply pressure to the combination control. Note 
the pressure reading on the manometer, then turn the 
valve off. A loss of pressure indicates a leak. If a leak 
is detected, use a soap solution to check all threaded 
connections. If no leak is found, combination control is 
faulty and must be replaced before putting appliance 
back in service.

Should maintenance be required, perform the following 
inspection and service routine:

1.  Inspect the area near the unit to be sure that there is 

no combustible material located within the minimum 
clearance requirements listed in this manual.