Installation Instructions

HM750A1000
33-00289EF—01 14
Fig. 24. Wiring the steam humidifier with a mechanical thermostat.
NOTE: If a Prestige, VisionPRO, Lyric (or similar) are used to control humidity, wire the two HUM contacts to terminals 1
and 2 on the HM750. With the jumper in place between terminals 1 and 8 on the HM750, only these two wires are
necessary to control humidity. Be sure to configure the control to force fan on with a call for humidity, or run on a
heat cycle if the fan enable wiring is not used.
HVAC
THERMOSTAT
R
C
U
U
S
S
GYWRRc
GYW
R
C
M37198
OUTDOOR
SENSOR
NOTE: SPDT RELAY IS NECESSARY TO PREVENT
ENERGIZING THE Y TERMINAL IF THE
THERMOSTAT DOES NOT ISOLATE Y AND G.
SPDT RELAY
COM
NC
NO
AIR PROVING
OR JUMPER
24VAC
COM
HUM
HUM
AP
AP
GT
RF
GF
Air Proving
Humidistat
External