8
7. Installation must include appropriate over current protec-
tion devices (fusing or circuit breakers) as required by ap-
plicable electric codes in the supply line to the unit. Refer
to nameplate for proper current ratings.
8. To operate heaters from an externally mounted hazard-
ous location thermostat, a terminal block is provided for
connection (Figures 9 and 10). Remove the factory in-
stalled jumper across T2 and T3 on the terminal strip.
Wire the thermostat contact leads to these terminals. The
built in control transformer supplies the unit with either
24V, 120V, or 230V (690V primary only) for internal unit
operation. This voltage will appear across the thermostat
contacts when they are open. The minimum thermostat
contact rating should be 1 amp @ 120 VAC. Refer to
nameplate for control voltage of unit. The 1/2 NPT con-
duit wiring entry on top of the terminal enclosure should
be used to wire the thermostat to the heater (Figure 10).
9. Protection against overheating is provided by a high
temperature cutout located within the heat exchanger
wiring compartment. (Figure 9) Activation of the control
will open the control circuit and energize the pilot lamp (if
supplied). If normal airflow is restricted, or stopped, the
unit will be cycled off by the high temperature cutout. The
high temperature cutout is also designed to shut down
the unit completely if the fluid level is low or other heater
malfunction occurs.
High Temperature cutout(s) must never be bypassed
in the control circuit. If the limit actuates, shut down
unit and investigate cause of abnormal operation. Do
not reenergize until the problem has been corrected.
Users should install adequate back-up controls and
safety devices with their electric heating equipment.
If the back-up controls are to be located in the haz-
ardous area, they must be approved for use in the
class of location. Where the consequences of failure
may be severe, back-up controls are essential.
Refer to Nameplate
for Input Voltage
1PH
L1 L2
Optional
Disconnet
Switch
GND
Optional Aux. Cont.
L1 L2 L3
Contactor
X1
H1
H2
X2
Primary
Secondary
Control Transformer
Refer to Nameplate for Primary (Input)
and Secondary (Control) Voltage.
Built-In or
External
Thermostat
Connect Thermostat Wires
to the Common and Normally
Closed Terminals of One Pole
on the Thermostat.
Remove this Wire when
Using Thermostat
T3
T2
T1
Optional Alarm
Optional
Elements
Manual Reset
High Limit
Auto Reset
High Limit
Motor
1PH
Terminal
Block
R
Diagram I - 1 PH Wiring
Transformer Color Code Tabulation
PRI
VOLT.
PRI. XFMR
LEAD CLRS.
120V SEC
LEAD CLRS.
24V SEC
LEAD CLRS.
H1
H2
X1
X2
X1
X2
208
BLK
RED
BLK
WHT
YEL
BLU
240
BLK
ORG
BLK
WHT
YEL
BLU
380
BLK
VIO
BLK
WHT
YEL
BLU
415
BLK
YEL
BLK
WHT
–
–
415
BLK
BRN
–
–
YEL
BLU
480
BLK BLK/RED
BLK
WHT
YEL
BLU
575/600 BLK
GRY
BLK
WHT
YEL
BLU
