Thermidistat Mode; Super-Dehumidify Mode; Continuous Blower Mode; Heat Pump - Carrier 58MVP Installation, Start-Up, And Operating Instructions Manual

speed, and the R to G-and-Y/Y2 circuits start the furnace
blower motor BLWM at high-cooling ariflow. High-cooling
airflow is based on the A/C selection shown in Fig. 50.
The electronic air cleaner terminal EAC-1 is energized with
115 vac whenever the blower motor BLWM is operating.
When the thermostat is satisfied, the R to G-and-Y1 or R to
G-and-Y1-and-Y2 circuits are opened. The outdoor unit stops,
and the furnace blower BLWM and electronic air cleaner
terminal EAC-1 will remain energized for an additional 90
seconds. Jumper Y1 to DHUM to reduce the cooling off-delay
to 5 seconds. (See Fig. 32.)

THERMIDISTAT MODE

See Fig. 54-57 for Thermidistat connections.
The dehumidification output, DHUM on the Thermidistat should
be connected to the furnace control thermostat terminal DHUM.
When there is a dehumidify demand, the DHUM input is activated,
which means 24 vac signal is removed from the DHUM input
terminal. In other words, the DHUM input logic is reversed. The
DHUM input is turned ON when no dehumidify demand exists.
Once 24 vac is detected by the furnace control on the DHUM
input, the furnace control operates in Thermidistat mode. If the
DHUM input is low for more than 48 hours, the furnace control
reverts back to non-Thermidistat mode.
The cooling operation described in item 3. above applies to
operation with a Thermidistat. The exceptions are listed below:
a. Low cooling-When the R to G-and-Y1 circuit is closed and
there is a demand for dehumidification, the furnace blower
motor BLWM will drop the blower airflow to 86% of
low-cooling airflow which is the true on-board CF selec-
tion as shown in Fig. 50.
b. High cooling-When the R to G-and Y/Y2 circuit is closed
and there is a demand for dehumidification, the furnace
blower motor BLWM will drop the blower airflow to 86%
of high-cooling airflow. High-cooling airflow is based on
the A/C selection shown in Fig. 50.
c. Cooling off-delay-When the "call for cooling" is satisfied
and there is a demand for dehumidification, the cooling
blower-off delay is decreased from 90 seconds to 5
seconds.

SUPER-DEHUMIDIFY MODE

Super-Dehumidify mode can only be entered if the furnace control
is in Thermidistat mode and there is a demand for dehumidifica-
tion. The cooling operation described in item 3. above also applies
to operation with a Thermidistat. The exceptions are listed below:
a. Low cooling-When the R to Y1 circuit is closed, R to G
circuit is open, and there is a demand for dehumidification,
the furnace blower motor BLWM will drop the blower
airflow to 65% of low-cooling airflow for a maximum of
10 minutes each cooling cycle or until the R to G circuit
closes or the demand for dehumidification is satisfied.
Low-cooling airflow is the true on-board CF selection as
shown in Fig. 50.
b. High cooling-When the R to Y/Y2 cicuit is closed, R to G
circuit is open, and there is a demand for dehumidifiation,
the furnace blower motor BLWM will drop the blower to
65% of high-cooling airflow for a maximum of 10 minutes
each cooling cycle or until the R to G circuit closes or the
demand for dehumidification is satisfied. High-cooling
airflow is based on the A/C selection shown in Fig. 50.
c. Cooling off-delay-When the "call for cooling" is satisfied
and there is a demand for dehumidification, the cooling
blower-off delay is decreased from 90 seconds to 5
seconds.

CONTINUOUS BLOWER MODE

When the R to G circuit is closed by the thermostat, the blower
motor BLWM will operate at continuous-blower airflow. Continu-
ous blower airflow selection is initially based on the CF selection
shown in Fig. 50. Factory default is shown in Fig. 58. Terminal
EAC-1 is energized as long as the blower motor BLWM is
energized.
During a call for heat, the blower BLWM will transition the blower
motor BLWM to continuous blower airflow, low-heat airflow, or
the midrange airflow, whichever is lowest. The blower motor
BLWM will remain ON until the main burners ignite then shut
OFF and remain OFF for the blower-ON delay (60 seconds in
low-heat and 35 seconds in high-heat) allowing the furnace heat
exchangers to heat more quickly, then restarts at the end of the
blower-ON delay period at low-heat or high-heat airflow respec-
tively.
The blower motor BLWM will revert to continuous-blower airflow
after the heating cycle is completed. In high-heat, the furnace
control CPU will drop the blower motor BLWM to low-heat
airflow during the selected blower-OFF delay period before
transitioning to continuous-blower airflow.
When the thermostat "calls for high-cooling", the blower motor
BLWM will operate at high-cooling airflow. When the thermostat
is satisfied, the blower motor BLWM will operate an additional 90
seconds at high-cooling airflow before transitioning back to
continuous-blower airflow.
When the R to G circuit is opened, the blower motor BLWM will
continue operating for an additional 5 seconds, if no other function
requires blower motor BLWM operation.
Continuous Blower Speed Selection from Thermostat
To select different continuous-blower speeds from the room
thermostat, momentarily turn off the FAN switch or push-
button on the room thermostat for 1-3 seconds after the blower
motor BLWM is operating. The furnace control CPU will shift
the continuous-blower airflow from the factory setting to the
next highest CF selection airflow as shown in Fig. 50.
Momentarily turning off the FAN switch again at the thermo-
stat will shift the continuous-blower airflow up one more
increment. If you repeat this procedure enough, you will
eventually shift the continuous-blower airflow to the lowest
CF selection as shown in Fig. 50. The selection can be
changed as many times as desired and is stored in the memory
to be automatically used following a power interruption.

HEAT PUMP

See Fig. 56-59 for thermostat connections.
When installed with a heat pump, the furnace control automatically
changes the timing sequence to avoid long blower off times during
demand defrost cycles. Whenever W/W1 is energized along with
Y1 or Y/Y2, the furnace control CPU will transition to or bring on
the blower motor BLWM at cooling airflow, low-heat airflow, or
the midrange airflow, whichever is the lowest. The blower motor
BLWM will remain on until the main burners ignite, then shut OFF
and remain OFF for 25 seconds before coming back on at heating
airflow. When the W/W1 input signal disappears, the furnace
control begins a normal inducer post-purge period while changing
the blower airflow. If Y/Y2 input is still energized, the furnace
control CPU will transition the blower motor BLWM airflow to
cooling airflow. If Y/Y2 input signal disappears and the Y1 input
is still energized, the furnace control CPU will transition the
blower motor BLWM to low-cooling airflow. If both the Y1 and
Y/Y2 signals disappear at the same time, the blower motor BLWM
will remain on at low-heat airflow for the selected blower-OFF
delay period. At the end of the blower-OFF delay, the blower
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