Honeywell H8908B Installation Instructions Manual page 3

WIRING
CAUTION
Personal Injury Hazard.
Power supply can cause electrical shock and
injury.
Disconnect power supply before installation or
servicing.
All wiring must comply with applicable local codes,
ordinances and regulations. Make wiring connections
according to humidifier (or dehumidifier/ventilator)
instructions, if available; otherwise, see typical wiring
diagrams in Fig. 5 through 12.
IMPORTANT
Select models of fan centers include humidifer
taps so the current sensing relay or sail switch
is not needed.
If not using a current sensing relay or sail
switch, the humidifier must be energized during
blower motor cycles for proper operation.
On multispeed blower applications, do not wire
the high voltage side of the transformer to the
same power source that services the furnace
blower. Premature transformer burnout can
occur.
On HE360 fan powered humidifier models, only
the two yellow wires are connected to the con-
trol. The remaining two red wires are only used
with electronic humidity controls.
L1
(HOT) POWER
FAN CONTROL
SUPPLY
L2
1
FURNACE
FAN
MOTOR
1 PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION
AS REQUIRED.
2 24 VAC WIRING.
Fig. 5. Typical wiring diagram for
system with fan interlock.
2
H8908B
TRANSFORMER
HUMIDIFIER
M13368
H8908B HUMIDISTAT/H8908C DEHUMIDISTAT
L1
(HOT) POWER
FAN CONTROL
SUPPLY
L2
1
H L
C
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
2 24 VAC WIRING.
Fig. 6. Typical wiring diagram for system
with 2-speed fan motor.
H8908B
TRANSFORMER
CURRENT
LO
SENSING
RELAY
C
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
2
24V WIRING.
Fig. 7. Typical wiring diagram of current
sensing relay with humidifier.
SAIL
SWITCH
TRANSFORMER
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS
AND OVERLOAD PROTECTION AS REQUIRED.
2 24V WIRING.
Fig. 8. Typical wiring diagram
of sail switch with humidifier.
FAN WIRING
TERMINALS
H8908B
1
HUMIDISTAT
TERMINALS
1 24V WIRING.
NOTE: FOLLOW THE INSTALLATION INSTRUCTIONS
INCLUDED WITH THE STEAM HUMIDIFIER
TO WIRE THE SYSTEM FAN.
Fig. 9. Typical wiring diagram for steam humidifiers.
3
H8908B
2
DPST
TRANSFORMER
SWITCHING
RELAY
2-SPEED
FAN
HUMIDIFIER
MOTOR
WATER
2
SOLENOID
LEAD WIRE
1
L2 L1
(HOT)
HUMIDIFIER
HI
M13386
H8908B
2
1
HUMIDIFIER
L2 L1
(HOT)
M13385
1
TO
SYSTEM
FAN
HUMIDIFIER
M13387
M13384
69-1341EF