Sterling VS - Manual (Page 23)

23
VARIABLE SPEED CONTROL
115 Volt Only (optional)
The Solid State speed controller may be installed at any
convenient location and is suitable for surface or fl ush
type mounting. A standard electrical single or double
gang wall box is recommended as in Figure 25.
Figure 25 - Wiring Diagram of Speed Control
Installation
Installation procedure:
1. Attach the control’s leads to the electrical leads in
the control box using wire nuts. The speed control
is to be wired in series with the motor. See wiring
diagram in Figure 25.
2. Make certain wire nuts are tight with no copper wire
being exposed.
3. Place wires and wire nuts back into box allowing
room for the control to fi t in box also.
4. Mount speed control to box using number 6
fl athead screws provided.
Setting the control:
1. Turn the control shaft fully clockwise. If the motor
is not running at the desired low speed, adjust the
trim on the face of the control for low speed setting
using a small screwdriver.
2. Rotate the control shaft counter clockwise. The
speed will increase smoothly from minimum to
maximum and then switch off.
VERTICAL LOUVER CONE DIFFUSER (optional)
Washers and bolts are provided with each louver cone
diffuser. Attach the diffuser to the bottom of the unit
heater as shown in Figure 26. Mounting holes are
provided in the unit base plate.
Adjust the diffuser to provide the desired air pattern.
NOTICE: To meet ETL and OSHA requirements, units
mounted below 8 feet (2.4m) must be equipped
with an OSHA fan guard. Vertical unit heaters can
support either an OSHA fan guard or the Louvered
Cone Diffuser - both items cannot be installed on the
same unit.
OPTIONS
Figure 26 - Louver Cone Diffuser
Attached to Vertical Unit Heater
STRAP-ON WATER CONTROL
A SPDT strap-on type hot water control with 100° to
240°F (38 to 116°C) rated at 10 amps at 120V is also
available. Control can be used for direct or reverse
acting applications as high or low limit.
STEAM PRESSURE CONTROL
SPDT switch opens on a rise in pressure. Control is
automatically reset, has a range of 0 to 15 PSI (0 to
103 kPa) and has an adjustable differential. Other
actions, ranges, circuits and manual reset models
are available on request.
THERMOSTATS
Line voltage wall thermostats are in stock for immediate
shipment. All models are SPST with bimetal thermometer,
knob-type set point adjustment, 40 to 90°F (5 to 30°C)
range and selector switches. Standard duty models
with “off-auto” and a heavy duty model with “auto-off-
fan” switching are available. Other models available on
request. Plastic tamperproof one size fi ts all thermostat
guards are also available.
WALL MOUNTED SPEED CONTROLLERS
Motors up to and including 1/8 HP (115V) can be
operated at reduced speeds by addition of optional
speed controller. Controller is 5 amps, pre-set at factory
for maximum and minimum speeds, with intermediate
speeds infi nitely controllable. All 1/3, 1/2 HP and 230V
motors operate only at rated speed and CFM – See
Charts.
MANUAL STARTERS
Single and three-phase models are available. Standard
models are single-speed, toggle-operated, NEMA Type
1 and are surface-mounted.
NOTICE: When using electrical accessories, always
refer to the accessory manufacturer’s installation
manual for proper use, location and wiring
instructions.