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HCSTEAM−16/−35 SERIES
Conventional 24 VAC
Humidistat (Cat no.
X9553 or equivalent)
NO
C
NC
C
NO
Alarm
terminals
(if used)
Outdoor AC Unit
Note 1. Blower interlock is required.
Note 2. 48G96 relay field supplied.
Note 3. Remove factory jumper between AB−AB
48G96 SPDT Interlock Relay
C
NO
Thermostat
Required Air Proving
Switch (provided)
GND
24VAC
N2
GND
N1
AB
AB
GND
IN
Typical Air Handler /
Furnace Control
(AHC or IFC)
(not
used)
(not
used)
Humidifier
low voltage
wiring panel
Figure 13. Humidifier with conventional 24V humidistat and interlocked with HVAC blower
S
When the humidity in the space falls below the conventional humidistat’s RH set point, the circuit closes from "GND" to "IN"
on the humidifier controller and in turn, closes the EXT FAN contacts ("NO" to "C") in the humidifier controller.
S
Terminal R on the furnace or air handler feeds 24V to the EXT FAN contacts (now closed) and to the blower interlock relay
coil. The interlock relay normally−open contacts close to energize G" on the furnace or air handler and start the indoor blower
(if not already running by a heating demand). The interlock relay also isolates G" from the thermostat to prevent a back feed
that would start the outdoor unit.
S
When the indoor blower achieves sufficient speed, the air proving switch contacts close completing the circuit from "AB" to
"AB" on the humidifier controller. Steam production will now start and continue until the humidistat demand is satisfied.
S
When the humidistat has reached its RH set point, its contacts open stopping steam production. The humidifier controller EXT
FAN contacts open, de−energizing the blower interlock coil and stopping the indoor blower (if not running due to a heating
demand or thermostat blower demand). When the indoor blower stops, the air proving switch contacts will open.
SLP98 Furnace /
CBX40 Air Handler
C
NO
Note 1. Do not connect H" on CS7000 to H" on furnace
or air handler control board.
Note 2. Set up humidifier per CS7000 thermostat installa-
tion instructions.
Note 3. 48G96 relay field supplied.
Note 4. Remove factory jumper between AB−AB.
Outdoor AC Unit
ComfortSense
®
7000
Thermostat
48G96 Relay
Alarm
terminals
(if used)
(not
used)
(not
used)
(not
used)
Required Air Proving
Switch (provided)
NO
C
NC
C
NO
GND
24VAC
N2
GND
N1
AB
AB
GND
IN
Humidifier
low voltage
wiring panel
Figure 14. Humidifier with ComfortSense
®
7000 thermostat used as humidistat and interlocked with
HVAC blower
S
Humidification is controlled by the humidity sensor in the thermostat
. When the humidity in the space falls below the thermo-
stat’s humidity RH set point, 24 volts goes on the thermostat’s "H" terminal to energize the humidifier isolation relay coil which
closes the open set of contacts in the relay, and completes the circuit between "GND" and "IN" on the humidifier controller.
S
The thermostat will also send power to the "G" terminal on the air handler or furnace control to start the indoor blower.
S
When the indoor blower achieves sufficient speed, the air proving switch contacts close completing the circuit from "AB" to
"AB" on the humidifier controller. Steam production will now start and continue until the humidity demand is satisfied.
S
When the RH set point is reached, the thermostat removes 24 volts from H" which opens the isolation relay circuit and, in
turn, opens the circuit between "GND" and "IN" on the humidifier controller, stopping steam production. The G" signal will
also be removed to turn off the blower (if not running due to a heating demand or thermostat blower demand). When the indoor
blower stops, the air proving switch contacts will open.
