37
PN 20009722 REV E, [02/11/2015]
WARNING
Electrical shock hazard. Before removing access
panels, verify all power is disconnected from unit.
Failure to follow these instructions could result in
death or serious injury.
!
TROUBLESHOOTING
Checking Fuse Link
To verify if fuse link has failed requires an Ohmmeter
reading across the limit switch.
1.
After disconnecting all power to unit, disconnect wires
from limit switch.
2.
With ohmmeter, check continuity across limit switch.
3.
If limit switch is open, it must be replaced.
For optional wall thermostat operation, 24Vac can also be
measured across Cassettes low-voltage terminals:
-“G” and “C” (fan signal).
-“W” and “C” (electric heat signal).
Figure 45 - Low-Voltage Interconnections -
IR Handheld Remote Controls with
Optional Wall Mounted Thermostat
CAW Infrared Control System
Cooling only units require 18 AWG minimum low-voltage
interconnecting wires.
- Terminal “W” is required for units with electric or hot
water heat only.
- Cassette controller will switch chilled water valve on
and off through yellow, “Y,” low-voltage terminal and
hot water through white, "W" and "C".
• When unit is calling for cooling, 24Vac can be measured
across terminals “Y” and “C” of unit.
• When unit is calling for hot water heating, 24Vac can be
measured across terminals "W" and "C".
• Indoor unit contains electronic anti-short-cycle timer
feature (ASCT) that will prevent unit from short cycling.
After room temperature is satisfied there will be three-
minute delay before unit is allowed to restart.
• Cassette controller or wall thermostat will also control
indoor fan by switching high-voltage power to fan motor
with fan relay. When energized, high-voltage power can
be measured between relay output and L2 terminal of
incoming power supply.
• For optional wall thermostat operation, 24Vac can also
be measured across low-voltage terminals “G” and “C”
of cassette.
Figure 44 - Low-Voltage Interconnections -
Wall Mounted Remote Thermostat
