
CACG/CAHG/CAHJ & CACH/CAHH/CAHK
Air Handlers
• Installation, Operation and Maintenance Manual •
Comfort where it counts
50
P/N 240008108, Rev. G [07/08/10]
Troubleshooting — General
WARNING
Service should be performed by a
quali-
fi ed service agency
and an annual system
check is recommended.
Electrical shock hazard
— Before re-
moving access panels or control covers
to expose moving parts of non-insulated
live electrical components for service,
disconnect all high-voltage power supplies
to both the indoor unit and outdoor unit.
Failure to do so could result in physical
injury and/or electrical shock.
Wiring diagram
When trouble shooting the indoor unit, please
refer to the wiring diagram that is supplied
with the equipment.
The wiring diagram is located on the
•
inside surface of the control panel cover
(see Figure 29, Page 22 ).
If you are unable to locate the wiring
•
diagram, please call the factory technical
service line at (800) 228-9364, and one
can be faxed, mailed or e-mailed. Please
have the full model and serial number
available prior to calling.
Wiring requirements
EMI air handlers are designed to operate with
EMI condensers.
Th
e air handle (indoor unit) and con-
•
denser (outdoor unit) must be indepen-
dently connected to the electrical service
panel and protected by separate time
delay fuse or HACR breakers. (See the
unit name plate for the correct breaker
type and size).
Th
e indoor and outdoor units are also
•
connected to each other via a 24V inter-
connect wiring. ( Figure 42, Page 51 or
Figure 43, Page 51 )
A transformer provides the low-voltage
•
power source for the controls. The
number of low-voltage interconnect
conductors will be two to six depending
on heating options and or thermostat
selection.
Interconnect wire should be at least
•
18 awg.
Refer to the unit wiring diagram for the
•
interconnect diagram that matches your
system.
Power supply check
When troubleshooting any EMI product, it
is important to fi rst check the rating plate for
proper fi eld voltage and breaker size.
Th
en use a voltmeter to check the incoming
power supply to verify that it agrees with the
rating plate.
Th
e incoming power must not exceed the
•
nameplate voltage.
Th
e incoming power must not be below
•
the minimum voltage stated on the rating
plate (197V for units rated 208/230V and
104V for units rated 115V).
Also verify low-voltage power — place a volt-
meter across low-voltage terminals R and C at
the indoor unit. Th
e voltage should be 24V.