Continuous Fan Mode; Component Test; Bypass Humidifier Mode - Carrier 58MVP Installation, Start-Up, And Operating Instructions Manual

3. Ignitor warm up—After prepurge period, HSI is energized
for 17 sec.
4. Ignition sequence—After HSI warm-up period is completed,
the gas valve is energized, permitting gas flow to the burners
where it is ignited. After 5 sec, the HSI is de-energized and a
2-sec flame-sensing period begins.
5. Flame sensing—When burner flame is sensed, control center
holds gas valve open.
If burner flame is not sensed, control center de-energizes gas
valve and ignition sequence is repeated.
6. Blower off period—Ten sec after gas valve is energized, the
blower stops for 25 sec to allow heat exchangers to warm up.
7. Blower on delay—After blower off period, blower starts.
NOTE: The blower starts at approximately 400-500 RPM. After
20 sec, the motor is turned off for 1/10 of a sec where a coast down
calibration is done to evaluate resistance of the conditioned air
duct system. The microprocessor then determines blower RPM
required to provide proper airflow for heating mode.
8. Electronic Air Cleaner—The EAC-1 terminal is energized
whenever blower operates.
9. Inducer speed reduction—If cycle starts in low heat, inducer
speed reduces slightly after the flame sense. If cycle starts in
high heat, inducer speed increases 15 sec after flame sense.
The reduction in speed in low heat is to optimize combustion
for maximum efficiency.
10. Call for heat terminated—When the call for heat is satisfied,
the R-W/W1 signal is terminated, de-energizing gas valve
(stopping gas flow to burners) and HUM terminal is de-
energized.
a. R-W/W1 signal terminated with R-Y/Y2 and R-G still
present—The blower changes its speed to cooling RPM.
b. R-W/W1 with R-Y/Y2 and R-G signals terminated—
The blower continues to operate completing a normal
blower off delay.
11. Post purge—The inducer continues operating for 15 sec after
gas valve is de-energized.
Step 7—Continuous Fan Mode
1. Operating with continuous fan only.
a. Call for continuous fan—The thermostat closes R-G
circuit.
b. Blower on—The blower starts immediately.
NOTE: The blower starts at approximately 400-500 RPM. After
20 sec, the motor is turned off for 1/10 of a sec where a coast down
calibration is done to evaluate resistance of the conditioned air
duct system. The microprocessor then determines blower RPM
required to provide proper airflow for heating mode.
NOTE: The continuous fan speed is the same as low-heat speed
unless it is field adjusted to another desired airflow. See Continu-
ous Fan Setup Switches section. There is also a chart on wiring
diagram. (See Fig. 23.)
c. Electronic Air Cleaner—The EAC-1 terminal is ener-
gized whenever blower operates, regardless of operating
mode.
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2. Operating with continuous fan (R-G) and call for heat
(R-W/W1) is received—Same as heat pump mode except
blower on delay is 10 sec less than the heat mode. After call
for heat (R-W/W1) is terminated, the blower remains operat-
ing at low-heat speed for selected blower off delay before
resuming continuous fan speed.
3. Operating with continuous fan (R-G) and call for cooling
(R-Y/Y2) is received—See Cooling Mode section. After call
for cooling (R-Y/Y2) is terminated, the blower remains
operating at cooling speed for 90 sec before resuming con-
tinuous fan speed.
Step 8—Component Test
All components are functionally operated except gas valve with
component test feature.
This feature helps diagnose a system problem in case of a
component failure.
NOTE: Setup switch SW-1 MUST be in OFF position or Fault
Code 22 (setup error) will occur.
NOTE: NO thermostat signal may be present at control center,
and all blower time delay off periods must be completed.
To initiate component test feature, proceed with the following:
1. Leave 115-v power to furnace turned on.
2. Remove main furnace door.
3. Remove blower access panel.
4. Turn setup switch SW-6 to ON position.
5. Manually close blower access panel door switch.
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Blower access panel door switch opens 115-v power to
control center. No component operation can occur. Caution
must be taken when manually closing this switch for service
purposes. Failure to follow this warning could result in
personal injury or death.
When items 1-5 have been completed, the following will occur:
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1. The control center goes through a brief self test. This self test
takes approximately 2 sec to complete. After door switch is
closed, red (microprocessor) LED briefly comes on. Then
green LED comes on for 1 sec, followed by 1 sec where both
green and yellow LEDs are on. During this time, the micro-
processor is checking itself.
2. Inducer motor operates for 20 sec at low speed, operates 20
sec at high speed, then turns off.
3. Hot surface ignitor is energized for 15 sec, then de-energized.
4. Main blower motor operates for 20 sec at low speed, operates
for 20 sec at high speed, then turns off.
5. After component operation test is completed, 1 or more fault
codes (11, 22, 41, or 42) will flash. See service label on back
of main furnace door for explanation of fault codes.
NOTE: To repeat component test, turn setup switch SW-6 to OFF
and then back to ON.
After component test, perform the following:
1. Release blower panel access door switch and turn setup switch
SW-6 to OFF position.
2. If applicable, replace blower access panel and check LED
status by removing plug in blower access panel.
3. Reinstall main furnace door if all LEDs are off, indicating
furnace is ready to operate when a signal from thermostat is
received.
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Step 9—Bypass Humidifier Mode
When setup switch SW-3 BPH is in ON position, RPM calculated
for low heat is multiplied by 1.15 for all furnace model sizes. This
compensates for increased return-air temperature caused by by-
passed air supply.
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