NOTE: The control center EAC terminals are sized for 12 gage
maximum, solid or stranded wire.
(4.) Route EAC leads through right-hand wire grommet.
(5.) Insert EAC stripped leads into control center EAC
terminals by depressing terminal’s arm with a screw-
driver or finger. (See Fig. 26.)
(6.) Reinstall control box to furnace blower shelf using 2
screws removed earlier.
2. Humidifier (HUM)
Screw terminals (HUM and C
OM) are provided for 24-v
humidifier connection. (See Fig. 24.) HUM terminal is ener-
gized with 24v (0.5-amp maximum) after inducer motor
prepurge period.
NOTE: A field-supplied, 115-v controlled relay connected to
EAC terminals may be added if humidifier operation is desired
during blower operation.
3. Dehumidification (DEHUM)
A dehumidification input is provided via a 1/4-in. male
quick-connect labeled DEHUM located next to the trans-
former secondary connections. When there is a dehumidify
demand, the DEHUM input is activated, which means 24 vac
signal is removed from the DEHUM input terminal. In other
words, the DEHUM input logic is reversed. the DEHUM input
is turned ON when no dehumidify demand exists and is turned
OFF when demand exists. This logic reversal has come about
from historical use of a standard humidistat to do dehumidi-
fication since the contacts open on high humidity, thus
removing the 24-v signal to initiate dehumidification.
The DEHUM output on the thermidistat control or the
humidistat output is connected directly to the DEHUM termi-
nal on the furnace control. In addition, the DE jumper located
next to the DEHUM terminal must be removed to enable the
DEHUM input. (See Fig. 27 and 28.) When a dehumidify
demand exists, the furnace control reduces the blower airflow
by 21 percent to 315 CFM per ton during continuous fan or
cooling operation.
DIRECT VENTING
The 58MVP Furnaces require a dedicated (one 58MVP furnace
only) direct-vent system. In a direct-vent system, all air for
combustion is taken directly from outside atmosphere, and all flue
products are discharged to outside atmosphere.
Fig. 26—EAC Terminals on Control Center
A93053
EAC2
EAC1
Fig. 27—58MVP Variable Speed Furnace Control
A99098
SEC-2
SEC-1
DE
W2 Com
24V
W/W1 Y/Y2 HUMRG
DEHUM
DE CONNECTION
DE CONNECTION
LOCATION
22
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