Sterling RT - Manual (Page 18)

18
Starting Unit in Heating Mode
1. Close the unit disconnect switch which provides
power to the unit.
High voltage is present in some
areas of the unit (primarily the main electrical
cabinet) with the unit disconnect switch closed.
Failure to exercise caution when working in the
presence of energized electrical components may
result in injury or death from electrical shock.
2. Set the thermostat/switching subbase as indicated
below:
a. position the heating system switch at either
HEAT or AUTO;
b. set the fan switch to AUTO.
3. Place the system switch in the ON position.
With the thermostat calling for heat, unit operation is
automatic.
Starting Unit in Cooling Mode
1. Close the unit disconnect switch which provides
power to the unit.
High voltage is present in some
areas of the unit (primarily the main electrical
cabinet) with the unit disconnect switch closed.
Failure to exercise caution when working in the
presence of energized electrical components may
result in injury or death from electrical shock.
2. Set the thermostat/switching subbase as indicated
below:
a. position the cooling system switch at either
COOL or AUTO;
b. set the fan switch to AUTO.
3. Place the system switch in the ON position.
With the thermostat calling for cooling, unit operation is
automatic.
Final Checkout
Run the unit sequentially through its stages of heating and
cooling. Once proper unit operation is verifi ed, perform
these fi nal steps:
1. Inspect unit for debris and/or misplaced tools and
hardware.
2. Be sure all gas valves and controls are in the operating
position if the unit will be operating immediately.
3. Cycle unit on all safety controls to verify proper unit
operation.
4. Confirm proper operating control (thermostat or
ductstat) operation by cycling unit.
5. Secure all exterior panels in place.
VI. MAINTENANCE
Open all disconnect switches
and secure in that position before servicing unit.
Failure to do so may result in personal injury or
death from electrical shock.
Gas tightness of the safety shut-
off valves must be checked on at least an annual
basis.
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.
These units have been developed for outdoor installation.
Maintenance is required and it is suggested that the
following unit servicing and inspections be performed
routinely. Also read in entirety and refer to the Outdoor
Duct Furnace Manual for maintenance requirements.
Service technician’s responsibility!
All safety controls must be checked! Check and
test the operational functions of all safety devices
supplied with this unit. Failure to do so could result
in unsafe conditions, and may result in death,
serious injury or property damage.
Inspect area near unit to be sure that there is no
combustible material located within the minimum
clearance requirements (See Figure 2). Service panels
provide easy access to the gas controls (located in duct
furnace section), the blower compartment, the electrical
cabinet and the supply plenum. To remove the service
door from any of these compartments, refer to access
panel removal section in beginning of this manual.
The pilot burner can be serviced by removing the pilot
plate from the main burner drawer assembly.
To remove the main burner drawer assembly (also refer
to Outdoor Rooftop Duct Furnace Installation and Service
Manual) for servicing the burners, proceed as follows:
1. Shut off the gas supply at the gas shutoff valve and
electrical power to the unit.
2. Break the union upstream of duct furnace gas valve
and loosen the union external to the furnace; swing
downward the piping to clear drawer.
3. Disconnect duct furnace gas valve wiring taking note
of all wire locations. Disconnect ignitor and fl ame
sensing probe wires at ignition control module and
any other wires.