Nortec NHDI - Manual (Page 12)

4, All blower packs require field wiring between
two pole primary voltage terminal blocks and
two low voltage control (class 1 circuit wiring
required) terminal strips; one of each located
in the humidifier and the remote blower pack
cabinet. To properly access the primary block
on the humidifier, it is necessary to open the
side pan. To connect the primary and control
(class 1 circuit wiring required) wiring, the
wiring is fed through the grommet provided in
the bottom of the blower pack. The terminal
block and strip are accessed by removing the
blower pack cover.
5. Field wiring of remote blower packs must
conform to national and local electrical codes.
Refer to wiring diagram supplied inside the
humidifier.
6. Use approved wire for power connection from
two pole terminal block of remote blower pack
to additional two pole terminal block inside
electrical section of humidifier.
7. Use approved wire to connect the ground
clamp of remote mounted blower pack to
ground clamp provided in the electrical section
of humidifier.
LOW VOLTAGE CONTROL WIRING
On-Off Controls
Controls are available from NORTEC as
accessories. If controls were not ordered with
humidifier, they must be supplied by others. The
following information is relevant to all controls, factory
supplied or otherwise.
A, B, C and D (described below) are to be wired in
series (only one path for current) across terminals 8
and 10 on the low voltage control terminal strip or
replaced with a jumper wire for constant operation.
Caution: this is the “hot” wire from the 24V control
transformer; it will blow the 3A fuse if any control field
wiring touches ground.
A - Wall or Duct Mounted Control On/Off
Humidistat: Wired to make on drop in humidity, break
on rise to set-point. Set to desired % RH. Can be a
make/break set of contacts from a Building Automation
System.
B - Duct Mounted Safety High Limit On/Off
Humidistat (if used): Wired to make on drop in
humidity, break on rise to safety set-point. Set to
approximately 85% RH as a safety to help prevent
saturation and wetting in the duct.
C - Duct Mounted Safety Air-Proving On/Off
Switch (if used): Wired to make with sensed air flow,
break when no air flow. Used as a safety to prevent
saturation when there is no airflow.
1. NORTEC offers various versions of A, B and
C to suit each application. In general, A is
essential, whereas B and C are highly
recommended in ducted applications.
2. Field wiring from humidistat to humidifier and
between devices should be 18 AWG or
heavier and kept as short as possible.
3. Low voltage control terminal strips are
provided in the electrical compartment.
Internal sides are factory wired. External
sides are to be field wired.
4. Each humidifier is supplied with a wiring
diagram inside.
D - Blower pack safeties
CONTROL INSTALLATION
1. Mount any wall humidistat (control or high
limit) over standard electrical box at height
similar to typical thermostat. Any wall
humidistat should be in location
representative of overall space being
humidified and not in path of blower pack or
air supply grille. Do not mount on a outside
wall where temperature fluctuation can affect
control response.
2. Mount duct humidistat in location
representative of overall air humidity, usually
in the return duct. Do not mount it directly in
front of steam distributor or in turbulent or
mixing zone. Mount it where humidity and
temperature are uniform and representative of
spaces being humidified.
3. Mount duct high limit humidistat
downstream of steam distributors far enough
that, under normal humidity and air flow
- 9 -
A
B
C
8 10 External
Internal
D
Figure #15
External Wiring of On/Off Controls