Gas Fired High Efficiency Unit Heater - General Maintenance

Note: The heater and vent system should be checked once a year by a qualified technician.

WARNING: Open all disconnect switches and disconnect all electrical and gas supplies and secure in that position before servicing unit. Failure to do so may result in personal injury or death from electrical shock.

WARNING: Gas tightness of the safety shut-off valves must be checked on at least an annual basis.

WARNING: Under no circumstances should combustible material be located within the clearances specified in this manual. Failure to provide proper clearance could result in personal injury or equipment damage from fire.

To check gas tightness of the safety shut-off valves, turn off the manual valve upstream of the appliance combination control. Remove the 3/32 hex head 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:

• 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.

• Turn off the manual gas valve and electrical power to the unit heater.

• Remove service access panel.

• To clean or replace the burner, remove retainer from around manifold orifice, disconnect flame sensor and igniter from control board, remove burner assembly mounting screws. See Figure 31.

• With the burner removed, wire brush the inside surfaces of the heat exchanger.

• Remove any dirt, dust, or other foreign matter from the burners using a wire brush and/or compressed air. Ensure that all parts are unobstructed.

• Reassemble the unit heater by replacing all parts in reverse order

• Complete the appropriate unit startup procedure as given in the “Operation” section of this manual. (See lighting instruction on the unit nameplate).

• Check the burner adjustment.

• Check all gas control valves and pipe connections for leaks.

• Check the operation of the automatic gas valve by lowering the setting of the thermostat, stopping the operation of the gas unit heater. The gas valve should close tightly, completely extinguishing the flame on the burner.

• 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.

Check lubrication instructions on motor. If oiling is required, add 1 or 2 drops of electric motor oil as follows:

• Light Duty - After 3 years or 25,000 hours of operation

• Average Duty - Annually after 3 years or 8,000 hours of operation

• Heavy Duty - Annually after 1 year or at least 1500 hours of operation.

Check and test the operational functions of all safety devices supplied with your unit.

• Pass
• Flag
• Fail

CAUTION: Never over oil the motor or premature failure may occur!