Reznor R6GP Unit Installation Manual - Manual (Page 20)

20
WARNING:
Label all wires prior to disconnection when
servicing controls. Wiring errors can cause
improper and dangerous operation.
3. Disconnect the wires from the gas valve, ignitor, and
flame sensor.
4. Using two wrenches, separate the ground-joint union
in the gas supply piping at the unit.
5. Remove the piping between the gas valve and the
ground-joint union, if necessary.
6. Remove the four screws securing the burner assembly
to the unit.
7. Carefully remove the burner assembly from the unit. DO
NOT DAMAGE THE IGNITOR OR FLAME SENSOR
WHILE REMOVING THE BURNER ASSEMBLY.
8. Remove three nuts securing the combustion blower to
the collector pan.
9. Remove the complete combustion blower from the unit.
10. Remove the screws securing the collector box cover
to the unit and remove cover plate.
11. Remove the screws securing the balance plate to the
collector box and the balance plate.
12. Remove the turbulator from each heat exchanger tube.
13. Attach a round wire brush to a length of high grade
stainless steel cable, such as drain cleanout cable.
Attach the other end of the spring cable to a variable
speed reversible drill. Slowly insert and rotate the cable
into the top portion of the heat exchanger. Operate the
drill alternating between forward and reverse, working
the cable in and out several times to obtain sufficient
cleaning. Repeat this sequence for each heat exchanger
tube.
14. Remove all loosened debris from the heat exchanger
tubes using a vacuum cleaner.
15. Using a light, check the condition of the upper and
lower sections of the heat exchanger tube.
16. Inspect the burners and if necessary, clean them
carefully with a soft wire brush and/or the nozzle of a
vacuum cleaner. DO NOT DAMAGE THE IGNITOR OR
FLAME SENSOR WHILE CLEANING THE BURNER.
17. Replace all the parts in reverse order from which they
were removed. NOTE: If screws or other hardware are
corroded, replace only with corrosion resistant stainless
steel hardware of similar design.
18. Follow the operating instructions found on the right
side door and the User’s Information Manual to return
the unit to operation.
High Pressure Switch
- This factory installed switch
is designed to de-energize the unit when excessive
pressure occurs due to abnormal conditions. Under normal
conditions, the switch is closed. If the discharge pressure
rises above 650 psig, then the switch will open and de-
energize the outdoor unit. The switch is a manually reset
type and will remain open until the button on top of the
switch is depressed.
Indoor Coil Freeze Protection Thermostats - The freeze
protection switches are designed to protect the indoor
coils from ice and frost accumulations in the event of a
loss of airflow by preventing the liquid refrigerant from
reaching the compressors. During normal operation, the
switches are closed and will open if the coil temperature
reaches 28° F (-2° C). The switches will close if the coil
temperature reaches 57° F (12° C).
Low Pressure Switch
- This factory installed switch is
designed to protect the compressor from a loss of charge.
Under normal conditions, the switch is closed. If the suction
pressure falls below 5 psig, then the switch will open and
de-energize the outdoor unit. The switch will close again
once the suction pressure increases above 20 psig.
Over-Temperature Limit Control - The over-temperature
limit control acts to prevent the air temperature leaving the
unit from exceeding the maximum outlet air temperature.
If the limit opens, the blower limit relay will energize. The
circulating air blower and combustion blower will continue
to operate if the over-temperature limit control opens.
The descriptions below are various functional components
that affect the operation and shutting down of this unit.
Some of these components and their locations are shown
in Figure 11 (page 21).
If any component on this unit must
be replaced, use only factory authorized replacement parts
specified in the Replacement Parts List provided online.
Centrifugal Switch
- The centrifugal switch acts to verify
that the inducer motor is running. Combustion gases are
drawn through the heat exchanger tubes and vented
through the vent system.
Flame Roll-Out Control - The flame roll-out control acts
to verify that the burner flame is being drawn into the heat
exchanger tubes. If the burner flame is not being drawn
into the heat exchanger tubes, the roll-out control will
open within several seconds. The combustion blower will
continue to operate if the flame roll-out control opens until
it is manually reset.
Flame Sensor - The flame sensor acts to prove that flame
has carried over from the ignitor to the right-most burner. If
no flame is sensed, the unit will be shut down automatically
and attempt two additional ignition trials before going into
lockout. Recovery from lockout requires a manual reset
by either resetting the thermostat or removing 24 volts
for a period of 5 seconds. If the thermostat is still calling
for heat after one hour the control will automatically reset
and attempt to ignite the burner again.
Gas Valve - The gas valve controls the flow of gas to
the burners in both low and high fire. When the valve is
energized, it automatically opens and regulates the gas
pressure to the manifold.
COMPONENT FUNCTIONS