AHRI (-)98VA060M317USA, Installation Instructions Manual

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CALIBRATION SEqUENCE OF OPERATIONS
WHAT'S UNIqUE ABOUT MPL
MODEL 9375 PRESSURE
SWITCHES
MPL Model 9375 pressure switches have calibrated Make
points (contacts close) versus calibrated Break points
(contacts open) experienced with most pressure switches
used in a Rheem furnace. The R97V downflow/horizontal
modulating furnace will calibrate inducer RPM’s based on
the Make point of the low, mid and high fire pressure
switches. T
CALIBRATION SEqUENCE OF
OPERATION
HONEyWELL CONTROLS Integrated Controls
with Direct Spark Ignition
A typical calibration sequence is performed prior to the
pre-purge under the following conditions:
1. The first gas heat call after cycling of main power (line
voltage).
2. Once every 1000 heat calls.
Notes:
1. During calibration, the IFC (Integrated Furnace Con-
trol) determines the minimum inducer RPM necessary
to keep respective pressure switches closed. The fea-
ture enhances the high energy efficiency experienced
with this model.
2. Burner compartment door must be ON furnace before
calibration sequence begins.
3. The IFC will finish the cold and warm calibration even
if gas heat call is removed during the calibration
process.
4. Duriing the initial or start-up call for heat, if the con-
densate trap has not been primed, a water sensed
fault (59) may occur during warm calibration. The gas
valve circuit will be de-energized and the calibration
sequence will begin anew.
Calibration Cycle
The seven-segment display “CL” (for Calibration) at the
start of the cold calibration and through the warm calibra-
tion sequence. Normal calibration sequence will take ap-
proximately 9.5 minutes to complete.
Cold Calibration- Low Pressure Switch
The IFC will energize the inducer at a low starting RPM
and increase the inducer speed until the low pressure
switch closes. At this point, the IFC notes the inducer RPM
when the low pressure switch closes and adds this value
to a predetermined value and saves the result in memory.
Cold Calibration- Mid. Pressure Switch
The furnace IFC will continue increasing the inducer RPM
until the mid. pressure switch closes. At this point, the IFC
notes the inducer RPM when the mid. pressure switch
closes and adds this value to a predetermined value and
saves the result in memory.
Cold Calibration- High Pressure Switch
The furnace IFC will continue increasing the inducer RPM
until the high pressure switch closes. At this point, the IFC
notes the inducer RPM when the high pressure switch
closes and adds this value to a predetermined value and
saves the result in memory.
Immediately following cold calibration the furnace IFC be-
gins a 30 second pre-purge period and up to a 7 second
Trial for Ignition (spark ignitor is energized). Following
burner ignition the furnace will begin a 2 minute warm-up
period. Following the warm-up period, the IFC will deter-
mine the necessary inducer RPM corresponding to the
open and closed points of the high, mid and low fire pres-
sure switches.
Warm Calibration- High Fire Pressure Switch
Inducer RPM will decrease steadily until the high fire pres-
sure switch opens. The inducer RPM is then increased
steadily until the high fire pressure switch closes. At this
point the IFC notes the inducer RPM when the high fire
pressure switch closes and adds this value to a predeter-
mined value and saves the result in memory. This value is
used as the target RPM for 70% to 100% firing rates.
Warm Calibration- Mid-fire Pressure Switch
Gas valve output is reduced to 65%. The inducer RPM is
decreased steadily until the mid-fire pressure switch
opens. The inducer RPM is then increased steadily until
the mid-fire pressure switch closes. At this point the IFC
notes the inducer RPM when the mid-fire pressure switch
closes and adds this value to a predetermined value and
saves the result in memory. This value is used as the tar-
get RPM for 50% to 65% firing rates.
Warm Calibration- Low Fire Pressure Switch
Gas valve output is reduced to 40%. The inducer RPM is
decreased steadily until the low fire pressure switch
opens. The inducer RPM is then increased steadily until
the low fire pressure switch closes. At this point the IFC
notes the inducer RPM when the low fire pressure switch
closes and adds this value to a predetermined value and
saves the result in memory. This value is used as the tar-
get RPM for 40% firing rates.
Calibration complete. Furnace will respond to thermostat
demand.
!
WARNING
SHOULD OVERHEATING OCCUR OR THE GAS
SUPPLy FAIL TO SHUT OFF, CLOSE THE MANUAL
GAS VALVE FOR THE APPLIANCE BEFORE
SHUTTING OFF THE ELECTRICAL SUPPLy.
FAILURE TO DO SO CAN CAUSE AN ExPLOSION
OR FIRE RESULTING IN PROPERTy DAMAGE,
PERSONAL INJURy OR DEATH.