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NOTE FOR OUTDOOR ENCLOSURE:
- Primary power should be routed through the grille at
the bottom of the unit.
- If backup heater is used, separate 240 supply must be
provided with disconnect brought to the Enclosure for
the heater. (Heater uses 20A- consult local codes for
wiring size) See installation drawing provided with the
heater for instructions on page 32. Note: Heater may
be plugged into 3-pronged, 30 ampere, 240 V outlet.
- If units operates during the summer, wire exhaust fan
provided with the enclosure (120Vwires supplied with
enclosure). Exhaust fan power can be the same sup-
ply then the power to the unit.
LOW VOL rAGE CONTROL WIRING
On/Off Signal Loop
(BModels)
A
sI
-r
C.l
Figure #7
External
Internal
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Available
All GH models require at least one type of input
control signal for unit operation. Refer to the sections
below that detail the types of controls that can be used
with each model.
Low voltage control terminal strips are provided in
the electrical compartment. Internal sides are factory
wired. External sides are to be field wired. Refer to
the specific control-wiring diagram supplied with each
unit.
Field wiring from humidistat to humidifier and
between devices should be 18 AWG or heavier and
kept as short as possible.
Controls are available from NORTEC as
accessories and can be ordered with the humidifier.
Controls by others maya/so be used as long as they
meet the criteria noted below. The following is a
summary of the common types of controls that may be
used with NORTEC Gas Humidifiers.
A - Wall or Duct Mounted Control On/Off
Humidistat: Wired to make on drop in humidity, break
on rise to setpoint. Set to desired RH. Can be a
make/break set of contacts from a Building Automation
System.
- 9 -
B - Duct Mounted Safety High Limit On/Off
Humidistat: Wired to make on drop in humidity, break
on rise to safety setpoint. Set to approximately 85%
RH as a safety to prevent saturation and wetting in the
duct. Highly recommended for ducted applications.
C - Duct Mounted Safety Air Proving On/Off
Switch: Wired to make when sensing air flow, break
when no air flow. Used as a safety to prevent
saturation when there is no air flow. Highly
recommended for ducted applications.
D&E - Wall or Duct Mounted Modulating
Humidistat: Provides a modulating signal to the unit
that represents the output (up to 100%) required from
the humidifier. Refer to the sections below that detail
the signal ranges that can be used with each model.
NOTE FOR OUTDOOR ENCLOSURE: Control
wiring should be routed through the grill at the bottom
of the unit.
GHB MODELS
GHB models will accept on/off controls only (see
A, B & C on figure #4.1). In general, A is essential
whereas Band C are optional. On/Off controls are to
be wired in series (only one path for current) across
terminals 1 and 2 on the low voltage control terminal
strip. All on/off controls used must be of the type that
the contacts are closed when operation is required and
open to shut off the unit. A jumper wire may be placed
. across these terminals to replace on/off controls and
provide for constant operation.
Caution: Terminal 1 is the "hof' wire from the
24Vac control transformer; it will trip the 3A breaker on
the transformer if any control field wiring touches
ground metal.
GHP MODELS
GHP models accept a single 0-10 VDC or 0-20
mA control signal (see D on figure #4.1) across
terminals 4 and 5 on the low voltage terminal strip to
generate a modulating output from the humidifier.
Terminals 1 and 3 are 24 Vac and ground respectively
and may be used to power a remote mounted
modulating humidistat.
An on/off security loop exists across terminals 1
and 2 and should be wired as described for GHB
models.
GHMC MODELS
GHMC models may be configured for either single
or dual channel modulation. Control signals can be
0-10 VDC or 0-20 mA (0-5 VDC, 1-5 VDC and 2-10
VDC are also available). The unit must be ordered
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