11
Wiring for Electrically Operated Humidifiers–EM Models
EM Models
STEP 9E (EM): Make Electrical
Connections
as recommended by the
manufacturers of the operators and
controls.
“EM” Series electric motor operated
humidifiers are furnished with a choice
of Honeywell M9182A operators,
Barber-Coleman MP361 or MP461, or
Belimo AF24SR or NVF24 electric
motorized operators. These operators
may be controlled by compatible
humidity controllers or electronic
humidity panels.
For all EM operators, mount
operator so that the motor shaft is
horizontal to the floor.
STEP 10E (EM): Install Temperature
Switch.
Remove cover of switch for
access to adjustable mounting strap.
Strap the switch to the humidifier drain
line piping just ahead of the steam
trap.
Solenoid Models
(DSA Models)
STEP 9E: Make Electrical
Connections
as diagrammed in Fig.
11-2. Be sure wiring is adequate for
the requirements of the system. Check
voltage ratings on operator nameplate.
STEP 10E: Install and Wire Humidity
Controller
as specified by the design
engineer and in accordance with
manufacturer’s instructions. If location
is not specified, the controller may be
installed in area controlled or in either
the return air or exhaust air ducts.
STEP 11E: Install Temperature
Switch.
Remove cover of switch for
access to adjustable mounting strap.
Strap the switch to the humidifier drain
line just ahead of the steam trap.
STEP 12E: Check Out Solenoid
Valve.
After making electrical
connections, move the humidity
setting indicator of the humidistat back
and forth past the point corresponding
with the actual room humidity. You
should be able to hear the solenoid
valve click open and click shut. For
test purposes a jumper will have to be
used on the temperature switch
connections since the function of this
switch is to prevent energizing the
solenoid until the humidifier reaches
steam temperature.
Auxiliary Controls
for All Models
Hi-Limit Duct Humidity Controller.
An enclosed switch type high limit
humidistat is recommended in the duct
at least 10 feet downstream from the
humidifier to override the controlling
humidistat. It is particularly
recommended with on/off models. This
high limit humidistat automatically
prevents local saturation at the point of
steam introduction. It also prevents
overloading the duct with vapor in the
event of failure of air conditioning
system components, incorrect control
settings or tampering.
Interlocks for Shudowns.
Humidifiers should be interlocked with
fans for shutdown on power failure or
other system trouble. Interlock should
be such that valve will go to the closed
position on a system shutdown rather
than be locked in its position at time of
shutdown.
Temperature Switch for Automatic
Warm Up.
This is a strap-on type and
is connected to the interlock system to
automatically keep valves closed
during warm up period after shutdown.
This will avoid the discharge of
condensate that can occur if steam is
admitted to cold humidifier piping
when the humidifier valve is open.
HC-201 High Limit Duct
Humidity Controller
(when used)
Temp. Switch
120 V. or 240 V.
24 V.
Transformer
M9182A (Series 90)
Motorized Operator
O
T
T
B
B
B
R
R
R
W
W
H915A (Series 90)
Humidity Controller
If High Limit Not Used
Wire R Directly to R
HC-201 High Limit Duct Humidity
Controller (Set at 90%)
(Used enclosed type switch)
Temp.
Switch
Solenoid
Interlock with Fan System
120 V. or 240 V. Single Phase
HC-101 Humidity Controller
Figure 11-1. Wiring diagram for HEM Series humidifiers using Honeywell M9182A
operator and H915A potentiometer controller.
Figure 11-2. Wiring diagram for 120v or 240v Solenoid
model humidifier. Wiring for auxiliary high limit duct
humidity controller and interlock for system shutdown is
shown in dotted lines.
NOTE: For wiring data covering Barber-Coleman operators, contact the factory or your Barber-Coleman dealer.
