Troubleshooting - Cach/Cahh Units - ECR EMI America Series Installation, Operation And Maintenance Manual

NOTICE
Cassette operation can be controlled
through either a remote thermostat or an
optional infrared handheld controller.
To select control method, refer to DIP
switch options, Table 6, Page 32.
Cooling-only units, Model CACH
Cooling only units require an 18 AWG low-
voltage interconnecting wires between the
indoor and outdoor units. If the cassette
controller is configured for remote thermostat
operation, then a wiring connection is also
required between the air handler and remote
thermostat. Refer to low-voltage interconnect
diagram, Figure 43, Page 51, for low-voltage
connections.
NOTICE
Terminal "W" is required for units with
electric heat only.
Terminal "C" may not be needed on
some thermostats.
The cassette controller or remote thermostat
will switch the outdoor unit on and off through
the yellow, "Y," low-voltage terminal.
When the thermostat is calling for cooling,
24 Vac can be measured across terminals "Y"
and "C" of the indoor or outdoor units.
For optional remote thermostat operation,
24 Vac can also be measured across low-volt-
age terminals "Y I" and "C" of the cassette.
The indoor unit contains an electronic anti-
short-cycle timer feature (ASCT) that will
prevent the outdoor unit from short cycling.
After the room temperature is satisfied there
will be a three-minute delay before the out-
door unit is allowed to restart.
The cassette controller or remote thermostat
will also control the indoor fan by switching
high-voltage power to the fan motor with
the fan relay. When energized, high-voltage
P/N 240007756, Rev. A [051509]
CACG/CAHG & CACH/CAHH
• Installation, Operation and Maintenance Manual •
Troubleshooting — CACH/CAHH Units
power can be measured between the relay
output and the L2 terminal of the incoming
power supply.
For optional remote thermostat operation,
24 Vac can also be measured across low-volt-
age terminals "G" and "C" of the cassette.
Heat Pump Units, Model CAHH
Heat pump units require an 18 AWG low-
voltage interconnecting wire between the
indoor unit and outdoor units. If the cassette
controller is configured for remote thermostat
operation, then a wiring connection is also
required between the air handler and remote
thermostat. Refer to low-voltage interconnect
diagram, Figure 43, Page 51, for low-voltage
connections.
Terminal "O" is required for heat pump
operation. The reversing valve is ener-
gized in cooling.
Terminal "W" is required for units with
electric heat only.
Terminal "C" may not be needed on
some thermostats.
Checking fuse link
Electrical shock hazard
to fully disconnect all power to both the
indoor cassette and outdoor unit where
indicated in these instructions.
To check if the fuse link has failed requires an
Ohmmeter reading across the limit switch.
1. After disconnecting all power to the unit,
disconnect the wires from the fuse link.
2. Then with an ohmmeter, check the con-
tinuity across the fuse link.
3. If the fuse link is open, it must be re-
placed.
55
Air Handlers
NOTICE
WARNING
— Make sure
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