Honeywell TrueSTEAM HM612A1000/U Installation Manual page 35

IMPORTANT NOTE: The images below are not complete wiring diagrams. It only depicts power monitoring and is not
meant to be a stand alone diagram. Please refer to the "Wiring the steam humidifier" section in the following pages for
complete wiring diagrams.
Steam Humidifier
HUM
HUM
Steam Humidifier
Humidity Control
HUM
HUM
Steam Humidifier System 69-2285—11
Thermostat with
Humidity Control
HVAC System
1 2 3
R
C
Thermostat
G
HVAC System
GT
R
GF G
WIRING BASICS: CONFIGURATION 1
When using a thermostat with integrated
humidity control (such as VisionPRO IAQ
or Prestige):
• A thermostat controls the fan and steam
humidifier. The control will not allow steam
production unless the system fan
is on.
• Wire Thermostat G to the HVAC system G
as normal.
• Wire steam humidifier HUM terminals to
the system HUM terminals.
M29617A
WIRING BASICS: CONFIGURATION 2
When using a humidistat separate from the
thermostat (such as H6062 or TrueIAQ):
• The external humidity control does not
monitor or control the system fan. Steam
humidifier must confirm that the fan has
power before allowing humidity.
• Break the thermostat G to HVAC system
G connection. Wire thermostat G to steam
humidifier GT. Wire steam humidifier GF to
HVAC system G.
• Thermostat G calls will pass directly
through steam humidifier. If this signal is
not present, and humidity is needed, steam
humidifier will relay power from its RT
M29618B
terminal to GF and out to HVAC system
G to ensure the fan has power for
humidity calls.
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