Service manual

27
All heating equipment should be serviced before each heating season to
assure proper operations. The following items may be required to have
more frequent service schedule based on the environment in which the unit
is installed, and the frequency of the equipment operation.
General Unit
When providing annual maintenance for the unit heater, keep the unit free
from dust, dirt, grease and foreign matter. Pay particular attention to:
1. The combustion air and exhaust vent piping.
2. The burner ports and pilot burner orifices (avoid the use of hard,
sharp instruments capable of damaging surfaces for cleaning these
ports). To check the burner port and pilot burner orifice, see Burner
and Pilot Assembly Removal.
3. The air shutters and main burner orifices (avoid the use of hard, sharp
instruments capable of damaging surfaces for cleaning these orifices).
To check the air shutters and main burner orifices, see for Manifold
Assembly Removal.
4. The heat exchanger. Clean tubes from the bottom with a stiff non-wire
brush.
5. The heat exchanger should be checked annually for cracks and
discoloration of the tubes. If a crack is detected, the heat exchanger
should be replaced before the unit is put back into service. If the tubes
are dark gray, airflow across the heat exchanger should be checked to
insure that a blockage has not occurred or the blower is operating
properly.
Electrical Wiring
The electrical wiring should be checked annually for loose
connections or deteriorated insulation.
Gas Piping & Controls
The gas valves and piping should be checked annually for general
cleanliness and tightness.
The gas controls should be checked to insure that the unit is operating
properly.
Propeller Assembly
Check the motor for lubrication if the motor is not perminatly lubricated.
Inspect the fan for damage and fit on motor shaft. Clean any dust, dirt or
foreign matter from the fan blades.
Blower Assembly
The blower assembly includes the bearings, drive sheaves and belts.
Blower bearings should be checked and lubricated based on the blower
manufacturer’s recommendations. Bearings should also be checked for any
unusual wear and replaced if needed.
Drive sheaves should be checked at the same time the bearings are
inspected. Check to make sure the sheaves are in alignment and are
securely fastened to the blower and motor shafts.
Belt tension should be rechecked shortly after the unit has been installed
to check for belt stretching. After the initial start-up, monthly checks are
recommended.
Manifold Assembly Removal
To remove the manifold
1. Shut off gas and electric supply.
2. Lower bottom pan to expose burner and manifold (see fig. 13.1)
3. Disconnect pilot tubing and thermocouple lead (or ignition cable)
at the combination gas control (and ignition control).
4. Disconnect control wires for the combination gas control.
5. Disconnect gas manifold at ground union joint.
6. Remove the two screws holding the manifold to the heat
exchanger support.
7. Clean the orifices and adjust the air shutters as necessary.
8. Follow steps 2-6 in reverse order to install the manifold
assembly.
9. Turn on the electric and gas supply.
10. Check the ground union joint for leaks with a soap solution.
Tighten if necessary.
Burner and Pilot Assembly Removal
To remove the burner
1. Shut off gas and electric supply.
2. Lower bottom pan to expose burner and manifold (see fig. 13.1)
3. Disconnect pilot tubing and thermocouple lead (or ignition cable) at
the combination gas control (and ignition control).
4. Remove the two burner retaining pins holding the burner in
place. The burner can then be easily lowered from the unit.
5. Examine the burner and pilot assembly for cleanliness
and/or obstructions as necessary (see General Unit for
cleaning instructions).
6. Replace the burner assembly in reverse order. In replacing the burner,
be certain that the slots at the front of the burner are located properly
on their shoulder rivets and that the burner retaining pins are put back
into their proper locations.
8. Reconnect the ignition cable and pilot gas supply line.
9. Turn on the electric and gas supply.
MAINTENANCE