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32 UH-SVX01A-EN
Electrical Connections: P
Model
ƽWARNING
Hazardous Voltage
Disconnect all electric power
including remote disconnects before
servicing. Failure to disconnect
power before servicing can cause
severe personal injury or death.
ƽWARNING
Hazardous Voltage
Do not use any tools (i.e.
screwdriver, pliers, etc.) across the
terminals to check for power. Use a
voltmeter. Failure to disconnect
power before servicing can cause
severe personal injury or death.
Standard units are shipped for use
on 115 volt, 60 hertz single phase
electric power. The motor nameplate
and electrical rating on the
transformer should be checked
before energizing the unit heater
electrical system. All external wiring
must conform to ANSI/NFPA No. 70-
2002, National Electrical Code (or the
latest edition) and applicable current
local codes; in Canada, to the
Canadian Electrical Code, Part 1 CSA
Standard C22.1.
It is recommended that the electrical
power supply to each unit heater be
provided by a separate, fused and
permanently live electrical circuit. A
disconnect switch of suitable
electrical rating for each unit heater
should be located as close to the
controls as possible. Each unit heater
must be electrically grounded in
accordance with National Electric
Code, ANSI/NFPA No. 70-2002 (or
the latest edition of) or CSA
Standard C22.1. Sample wiring
connections are depicted in
Figure 38 through Figure 40.
Operation
Most basic unit heater systems are
controlled by a room thermostat.
Locate thermostat on inner wall or
column so that optimum control
could be obtained for that area. Set
thermostat for desired temperature.
On steam systems a low limit may
be used to prevent fan from blowing
cold air unless the heater has steam
passing through the coil.
Small hot water systems could have
the circulating pump controlled
directly by the room thermostat. On
large systems, zone valves could be
used to control the individual unit
heater where constant water
circulation is used on the main
system.
A louvered cone air diffuser is
readily available as an optional
accessory for vertical unit heaters.
See catalog for details.
Thermostat Wiring and Location
Note: The thermostat must be
mounted on a vertical
vibration-free surface free
from air currents and in
accordance with the
furnished instructions.
Mount the thermostat approximately
5 feet (1.5 m) above the floor in an
area where it will be exposed to a
free circulation of average
temperature air. Always refer to the
thermostat instructions as well as
our unit wiring diagram and wire
accordingly. Avoid mounting the
thermostat in the following
locations:
1. Cold areas - Outside walls or
areas where drafts may affect
the operation of the control.
2. Hot areas - Areas where the
sun’s rays, radiation, or warm air
currents may affect control
operation.
3. Dead areas - Areas where air
cannot circulate freely, such as
behind doors or in corners.
Note: For all wiring connections,
refer to the wiring diagram
on the motor nameplate.
Should any original wire
supplied with the heater
have to be replaced, it must
be replaced with wiring
material having a
temperature rating of at least
105° C.
Motors
The standard 115/1/60 motors
provided on Vertical Unit Heaters are
totally enclosed, Class “B” insulated
and have built-in thermal overload
protection.
Vertical Units 42 through 80 use
sleeve type bearings. Vertical Units
122 through 280 use permanent split
capacitor motors with ball bearings.
All sleeve bearing motors have oil
holes to allow lubrication. Ball
bearing motors are permanently
lubricated although some three
phase or special motors have
removable plugs which will allow
field installation of grease fittings.
The standard 42 through 102 motors
can be converted to variable speed
operation with the addition of the
solid state speed control.
See Figure 32 through Figure 37 for
typical wiring diagrams.
Electrical Connections