H8908A/B HUMIDISTAT; H8908C/D DEHUMIDISTAT
5
69-1341EF—07
Fig. 15. Wiring H8908 in line with
air pressure switch/sail switch and humidifier.
Fig. 16. Wiring H8908 with steam humidifiers.
Fig. 17. Wiring H8908 with VisionPRO® IAQ on typical 2-stage furnace.
Fig. 18. Wiring H8908 with VisionPRO®
Thermostat for dehumidification.
Fig. 19. Typical wiring diagram for HR150,
HR200, ER150 and ER200 Ventilator
or DH90 Dehumidifier applications.
M24730B
L1
(HOT)
L2
1
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
24V WIRING.
HUMIDIFIER
TRANSFORMER
AIR
PRESSURE SWITCH/
SAIL SWITCH
H8908
10
OFF
ON
20
30
40
50
60
2
M24731
1
1
1
FOLLOW THE INSTALLATION INSTRUCTIONS
INCLUDED WITH THE STEAM HUMIDIFIER
TO WIRE THE SYSTEM FAN.
NOTE:
HUMIDIFIER
TO
SYSTEM
FAN
HUMIDISTAT
TERMINALS
FAN WIRING
TERMINALS
24V WIRING.
H8908
10
OFF
ON
20
30
40
50
60
EQUIPMENT INTERFACE MODULE
M24724B
H8908B
10
OFF
ON
20
30
40
50
60
1
2
3
C
R
RC
RH
1
2
3
24 VAC
H1
U
M2
D1
H
M2
V1
N
T2
OR
L
NOT USED
OUT1
OUT2
IN1
IN2
DATS1
DATS2
CONV. HP
W1
W2
W3
Y
Y2
G
O/B
AUX
AUX2
Y
Y2
G
TH9421 VISION PRO
THERMOSTAT
24 VOLT
TRANSFORMER
SYSTEM
TRANSFORMER
S688 AIR
PRESSURE
SWITCH/
SAIL SWITCH
COM N.O. N.C.
C
R
L2
L1
C
R
L2
L1
HE225/HE265
HUMIDIFIER
STAGE 1
HEAT
STAGE 2
HEAT
COMPRESSOR
C7089U1006
FAN
RELAY
HEATING
RELAY OR
VALVE COIL
COOLING
CONTACTOR
COIL
FAN
RELAY
COIL
PROVIDE OVERLOAD PROTECTION
AND DISCONNECT MEANS AS REQUIRED.
M24725
1
1
VISIONPRO® THERMOSTAT
Y2
L
A
W2
S1
S2
RC
R
W
Y
G
C
H8908D
10
OFF
ON
20
30
40
50
60
VENTILATOR/DEHUMIDIFIER
M24732
TERMINALS
Fresh Air Ventilation System
Système de ventilation à air frais
H8908D
10
OFF
ON
20
30
40
50
60
