9
*
Actual
switch
settings
may
vary.
See
Fig.
23-1
for
explanations
or
consult
factory.
High Limit Humidistat
Remove the jumper tab from terminals 24 & 25 and wire the high limit stat between these
terminals. Refer to Figure 8-1 (the overall wiring diagram) for more information. A duct mounted
high limit humidistat is recommended to prevent over-saturation of the duct air. Use an on-off
controller that opens on fault (high humidity). Humidistat should be set for a maximum of 90%
RH. Alternately, a modulating high limit humidistat may be used on applications such as variable
air volume (VAV). Locate the high limit humidistat approximately 10’ (3m) downstream of the
dispersion manifold. If 10’ (3m) is not available, consult the factory. Note: High limit humidistat
will be wired in series with duct pressure switch, if used, see Figure 8-1.
Airflow/Pressure Switch
An airflow switch is recommended to deactivate the humidifier when there is insufficient air flow
in a duct system. A duct pressure switch is preferred as an airflow sensor. The pressure switch
should open on insufficient airflow (opens on fault). Airflow switch should be mounted in supply
air duct upstream of humidifier dispersion. Remove the jumper tab between terminals 24 and 25
and wire the airflow sensor between these terminals. See Figure 8-1 (the overall wiring diagram)
for more information. Complete installation and wiring instructions are contained in the duct
pressure switch package. Note: Duct pressure switch will be wired in series with high limit
humidistat, if used, see Figure 8-1.
Alarm Circuit
The bottom 2 terminals on the TB2 connector on PC board, see PC Board drawing
Fig. 9-1 on Page 9, are connections for a class II NEC alarm circuit (switch closure only,
1 amp. maximum @ 24 Vdc or 0.5 amp. @ 125 Vac). The switch will close when the error or service
LED’s are energized except when high humidity/sail switch circuit is open.
Actual
switch
setting
may
vary.
Please
see
page
8,
item
3.
Figure
9-1
PC
Board
Voltage
Source
Jumper
Please
see
Fig.
8-2
for
proper
setting.
J3
*
