Reznor R6GI Unit Installation Manual - Manual (Page 20)

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11. The inducer motor is de-energized after a 30 second
post purge.
12. The circulating air blower will remain energized for
approximately 120 - 150 seconds after the demand
for heat is no longer present.
13. Abnormal Conditions - If a limit switch opens during
heating operation the gas valve is de-energized
immediately. The control de-energizes the induced draft
motor and runs the indoor blower motor continuously
while the limit switch is open.
Cooling Mode
Before the first start after power-up and between cycles
there will always be a 5 minute (re)start delay imposed.
With a call for cooling and before the compressor is turned
on, the outdoor fan will run for 1 minute to assure that
the outdoor temperature measurement is close to that of
the ambient air. The compressor will then ramp up to a
speed selected by the capacity control scheme.
The unit is a true variable speed unit. Normally the
compressor will operate at one of 5 speeds in cooling,
each predetermined for a balance of optimum efficiency
and capacity.The outdoor fan motor and indoor blower will
also operate at multiple speeds, following the compressor.
For cooling mode, the speeds used will depend on several
factors, including:
• Whether first or second stage operation is called for by
the thermostat (which must be two stage-capable),
• Outdoor ambient temperature.
• The length of time the equipment has been operating
during the current cycle
• The operating speed history, for both the current and
the previous operating cycles.
For example, with a first stage call in cooling, if the setpoint
was satisfied quickly, the unit will restart the next time
at a lower speed. At a low or intermediate speed, if the
setpoint is not satisfied within 60 minutes, the speed will
be increased. If the unit cycles off after having a speed
increase, the entire next cycle will be at the higher speed.
Also, the outdoor fan will run for an extra minute after the
compressor shuts off.
The actual current operating compressor speed can be
determined by checking the 2-character display on the
interface board. Refer to
Figure 14 (page 31) , Figure
15 (page 32) , and Table 17, (page 31) .
The blower speeds for the various cooling stages
are programmed and controlled in accordance with
compressor speeds. It is possible to adjust blower airflow
if required by application, in which case the controller will
adjust all speeds according to the adjusted nominal speed.
The airflow is set by DIP switches on the blower control
board, providing one flow for second stage compressor
speeds and a lower flow for first stage compressor speeds.
De-Humidification Control
If installing a humidistat, install it in the return air duct
as directed in the installation instructions included in the
accessory kit. Run the humidistat wiring through the low-
voltage wire entrance in the packaged unit and connect
one side of the humidistat to the R terminal of the low
voltage field connection board & the other side to the
DEHUM terminal located on the blower control board.
Wire the humidistat to close on rise in humidity.
For dehumidification, the Dehum input on the VSHE board
can be used to control this function. If the Dehum input is
active and the unit is operating in second stage cooling,
the following will happen. The suction line temperature
sensor is used for coil temperature.
• The blower CFM is 75% of cooling value for the operating
speed.
• If coil temperature is less than 37 0 F for 30 seconds,
then blower CFM is set to 85% of cooling value. If coil
temperature rises above 37
0 F for 5 minutes, then blower
runs at 75% of cooling value.
• If coil temperature is less than 35 0 F for 30 seconds,
then blower CFM is set to 100% of cooling value. If
coil temperature rises to between 35
0 and 37 0 F for 5
minutes, then blower CFM is set to 85% of cooling value.
If coil temperature rises above 37
0 F for 5 minutes, then
blower CFM is set to 75% of cooling value.
Delay Override
When performing startup tests or troubleshooting, the 5
minutes startup delay can be skipped by shorting the two
J4 Test pins indicated in
Figure 14 for about 1 second
while the compressor is off and waiting to start.
NOTE: This will also clear the faults stored in memory.
Fan Only Mode
1. On a call for fan only operation, the thermostat applies
24 VAC to the G terminal on the furnace control board.
2. The circulating air blower ramps to 1/2 of the selected
airflow.
EQUIPMENT MAINTENANCE
WARNING:
ELECTRICAL SHOCK, FIRE OR
EXPLOSION HAZARD
Failure to follow safety warnings exactly could
result in serious injury or property damage.
Improper servicing could result in dangerous
operation, serious injury, death or property
damage.
• Before servicing, disconnect all electrical
power to furnace.
• When servicing controls, label all wires
prior to disconnecting. Reconnect wires
correctly.
• Verify proper operation after servicing.