Detroit Radiant Products Company UH Series - Manual (Page 50)

50
UH Series
5.0 Maintenance
To check gas tightness of the safety shut off valves, turn off the manual valve upstream of the appliance
combination control. Remove the 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. Any 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. 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.
2 Turn off the manual gas valve and electrical power to the unit heater. Remove service access panel.
3 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. With the burner
removed, wire brush the inside surfaces of the heat exchanger.
4  Remove any dirt, dust, or other foreign matter from the burners using a wire brush or compressed
air. Ensure that all parts are unobstructed. Then reassemble the unit heater by replacing all parts in
reverse order.
5 Complete the appropriate unit startup procedure as given in the Operation section of this Manual.
(See lighting instructions on the unit nameplate.)
• Check the burner adjustment.
• Also check all gas control valves and pipe connections for leaks.
6 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.
7 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.
8 If combustion air is room supplied, ensure that a 12 inch clearance is maintained all around the inlet
openings.
9 Check lubrication instructions on motor. If oiling is required, add three or four drops of SAE 20 electric
motor oil:
• After three years or 25,000 hours (for light-duty operation).
• Annually after three years or 8,000 hours (for medium-duty operation).
• Annually after one year or 1,500 hours (for heavy-duty operation).
Never over-oil the motor, or premature failure may occur.
10 Check and test functions of all safety devices supplied with the heater.
5.0 Maintenance
NOTICE