16
OPTIONS
(5) Control Step Down Transformer - (STD)
The control step down transformer is located in the electrical
junction box. The transformer is used to step down the supply
power (115V, 208V, 230V, 460V, 575V) to 24V. This transformer
is used to control the gas controls, fan delay relay, field
supplied motor starter, etc. All unit heaters are supplied with a
40VA control step down transformer. To determine the control
transformer supplied as well as any accessory/ field supplied
transformers required reference the supply voltage listed on the
serial plate and reference tables 16.1 and 16.2.
(6) High Limit Switch - (STD)
The automatic reset high limit switch is factory installed on
the left side (air blowing you in the face) of the unit heater. If
the limit temperature is exceeded, the gas controls are de-
energized until the switch is cooled.
(7) Pressure Switch (STD)
A automatic reset vent pressure switch is supplied on all Power
vented unit heaters and is designed to prevent operation of
the main burner in the event there is restricted venting of flue
products. This restriction may occur due to an improper vent
diameter, long vent runs, un-approved vent terminal, high
winds, high negative pressure within space, etc. After the cause
of the restriction has been corrected, the pressure switch will
reset automatically. See trouble shooting section for more
information.
(8) Power Exhauster (STD)
All power vented unit heaters are supplied with a round vent
pipe connection. Some models may require the use of a vent
transition from the power exhauster outlet to the vent pipe (See
table 6.1). The power exhauster may be rotated 180° to allow
for various venting directions.
(9) Blower Motor - (OPT)
The blower motor is factory installed on the blower housing. The
blower motor can be provided in a variety of supply voltages
and motor horsepowers. Refer to the model nomenclature to
determine the motor provided. The blower motor is supplied
with an adjustable sheave that can be used
to increase/decrease the blower RPM. For instructions on
changing the blower RPM, refer to Blower Adjustments.
Unit Power
(As found on Serial Plate)
Voltage Phase Voltage Phase
115 1 115 1 11,25,30,59,63,81,83,85,87,89 115 to 24 none
200-208 1 115 1 11,25,30,59,63,81,83,85,87,89 115 to 24 208V to 115V
200-208 1 200-208 1 12,26,31,60,64,82,84,86,88,90 200-208 to 24 none
200-208 3 115 1 11,25,30,59,63,81,83,85,87,89 115 to 24 208V to 115V ➀
230 1 115 1 11,25,30,59,63,81,83,85,87,89 115 to 24 208 to 115V ➀
230 1 230 1 12,26,31,60,64,82,84,86,88,90 230 to 24 none
230 3 115 1 11,25,30,59,63,81,83,85,87,89 115 to 24 230V to 115V ➀
460 3 115 1 11,25,30,59,63,81,83,85,87,89 115 to 24 460 to 115V
575 3 115 1 11,25,30,59,63,81,83,85,87,89 115 to 24 575 to 115V
Table 16.1
Electrical Details Propeller Units
➀ A transformer may not be required. 115V/1φ power may be obtained from the following electrical distribution systems: 230/1φ 3-wire, 230/3φ
4-wire, 208/3φ 4-wire and 208/1φ 3-wire (from 208V wye connected transformer). Please consult the job site electrician to determine applicability.
➁ Unit power code must match building supply voltage, control voltage must match unit power.
➂ For CSA Canada certification, step down transformer may be required to be factory installed (Blower Models Only).
Power
Building Supply
Voltage
Control Code Selected
Factory
Installed
Transformer
Additional
Field Installed
Transformers
Table 16.2
Electrical Details Blower Units
Unit Power
(As found on Serial Plate)
Voltage Phase Voltage Phase
115 1 115 1 11,25,30,59,63,81,83,85,87,89 115 to 24 none
200-208 1 200-208 1 12,26,31,60,64,82,84,86,88,90 200-208 to 24 none
200-208 3 200-208 3 12,26,31,60,64,82,84,86,88,90 200-208 to 24 none
230 1 230 1 12,26,31,60,64,82,84,86,88,90 230 to 24 none
230 3 230 3 12,26,31,60,64,82,84,86,88,90 230 to 24 none
460 ➁ 3 230 ➁ 3 26,60,64,84,88,90 230 to 24 460 to 230V ➂
460 3 460 3 3,32,9,93 460 to 24 460 to 230V
575 ➁ 3 230 ➁ 3 26,60,64,84,88,90 230 to 24 575 to 230V ➂
575 3 575 3 14,33,92,94 575 to 24 575 to 230V
Power
Building Supply
Voltage
Control Code Selected
Factory
Installed
Transformer
Additional
Field Installed
Transformers
