35
PN 20009722 REV F, [08/01/2020]
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
Wiring Diagram
Troubleshooting indoor unit, see wiring diagram(s) supplied
with equipment.
• Wiring diagram located on inside surface of control panel
cover. See Figure 27, Page 17.
Wiring Requirements
• Air handler may be protected by separate time delay
fuse or HACR breakers. See unit name plate for correct
breaker type and size.
• Transformer provides low-voltage power source for
controls. Interconnect wire should be at least 18 AWG.
• See unit wiring diagram for interconnect diagram that
matches your system.
Power Supply Check
Check rating plate for proper field voltage and breaker size.
Use voltmeter to check incoming power supply. Verify
power supply agrees with rating plate.
• Incoming power must not exceed name plate voltage.
• Incoming power must not be below minimum voltage
stated on rating plate (197 Vac for units rated 208/230
Vac).
Wall Mounted Thermostat - CAW Units
Low volt interface requires 18 AWG low-voltage
interconnecting wires.
• Terminal “W” is required for units with electric or hot water
heat only.
• Terminal “C” may not be needed on some thermostats.
• Wall mounted thermostat controls cooling through
black, “Y,” and "C" wires.
• Wall mounted thermostat controls
heating
through
white, “W,” and "C" wires.
When thermostat is calling for cooling, 24Vac is measured
across terminals:
• “Y” and “C” of water valve.
• “Y1” and “C” of cassette.
While wall thermostat is calling for cooling or heating and
anti-short-cycle-timer delay has elapsed, 24Vac can be
measured between terminals:
• “Y” and “C” of water valve for cooling.
• “Y1” and “C” cassette for cooling.
• “G” and “C” cassette (fan signal).
• "W" and "C" for heating.
Electric Heat (Optional)
Units with electric heat utilize control relay located on
circuit board in control box. Wall mounted thermostat
calling for electric heat relay energizes.
To verify electric heat operation, place wall thermostat
in Heat mode with setpoint temperature above room
temperature.
• Place clamp-on type ammeter on one leg of incoming
power supply.
• When unit is working correctly, amp reading should
correspond with values in table below.
• Following current values apply when unit is connected to
230Vac power supply. Values include fan motor current.
If supply voltage is different, this will affect amp draw of
heater.
5kW = 22.7 A
3kW = 13.6 A
1.5kW = 6.9 A
•
Electric heat relay can also be verified by placing
voltmeter across high-voltage relay output terminal and
incoming power L2 terminal.
• If unit is working correctly, reading should be same as
measured across incoming power supply.
Auto-Reset Limit Switch
As safety feature, an auto-reset limit switch is located on
heater assembly.
• Limit will interrupt power to heater if over-temperature
condition occurs.
• Each limit switch is also equipped with one-time fuse
link.
• Should electric heat temperatures rise above auto
resetting limit switch, non-resetting, one-time fuse link
will open and heater will remain off.
• If this occurs limit switch assembly must be replaced.
