FUJITSU GENERAL AMERICA, INC
SERVICE BULLETIN
353 Route West. Fairfield, NJ 07004
Ph: 973-575-0381 Fx: 973-836-0449
Number: 0006
Date: 9/22/09 Rev2
Em: ServiceHVAC@fujitsugeneral.com
Type: Field
Fresh Air Intake w/ Compressor Operation OnlyPROBLEM
Duct Fan ControlSOLUTION
Production: All CassettesMODEL :18/24/36/42RLX Systems
1. Outline
The circuit shown below provides a cost effective solution for wiring a current switch
that monitors the compressor operation ON/OFF status and energizes the coil of a
relay which in turn close the contacts and provide line voltage to the duct fan. The
duct fan is required to introduce fresh (outside) air for ventilation.
2. Application
A third party current sensor switch with a built-in relay was
used in this application. The current sensor may be
installed around one of the compressor line voltage wires (Red,
Black or White).
3. Wiring diagram
IPM
24V DC
115V AC
+
_
Current Sensor
N.O.
N.O.
N.O.
Built in Relay
Compressor
Duct fan booster
4. Components utilized
Current sensor with built-in relay specifications:
Split Core Fixed Threshold Current Status Sensor with Command Relay and
Switching Power Supply.
FGAI Fresh Air Kit Part # KHRS940-25
5. Recommended Fan size.
Duct and Fan are field supply. A fan capable of generating 15 CFM at a
static pressure of approximately .26 inches W.C.
Wiring
•Recommended wire size- 14 AWG.
10A Fuse
(Field Supply)
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