16
FIELD WIRING DIAGRAMS — TYPICAL
ELECTRIC DEFROST — 208/230/1/60 — (1) UNIT COOLER WITH HEATER CONTACTOR
IMPORTANT WIRING NOTES
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INSTALLER PLEASE READ CAREFULLY!
Sub-circuit fusing or service disconnect switches are not shown but may be required as per the NEC and / or local codes.
It is the responsibility of the installing contractor to interpret and comply with all applicable electrical codes.
Field install an 18 GA jumper wire between terminals 3 & 4 on terminal block TB2 for continuous low speed fan operation (950
RPM). Fan motors will operate continuously on high speed without jumper wire installed (F31 Models Units - 1300 RPM / F35
model units - 1450 RPM). See page 21 for optional two speed fan relay control wiring if required.
The defrost time clock, block out relay / auxiliary switch and heater contactor are typically located in the system condensing
unit. All unit cooler power should feed from this unit. Make sure the total heater amp draw does not exceed the resistive rating
of the contactor. Also be sure the wire gauge size is adequate to carry the total amp load required.
When using a heater contactor with unit cooler defrost heaters factory wired for single phase remove factory installed jumper
between terminals 2 & 3 on TB1 and wire directly to heater contactor as shown above.
The room thermostat and liquid line solenoid valve are shown as field installed but may be factory mounted in the unit cooler.
Make sure the solenoid holding coil is wired for the correct control voltage (115 or 230).
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