10 Troubleshooting - Honeywell CT500 Owner's Manual

10 TROUBLESHOOTING

See Table 3 to troubleshoot your thermostat.
Symptom
Heating/cooling
equipment does not
operate.
Partial display.
No display.
Temperature display
is incorrect.
Cannot change
temperature setting.
Snowflake is
flashing.
System on indicator
(flame=heat) is
displayed, but no
warm air is coming
from the registers.
Table 3. Troubleshooting Your Thermostat.
Possible Cause
No power to the
thermostat.
System switch on
thermostat not in
correct position.
Thermostat minimum-
off times operating for
cooling.
Incorrect wiring.
Heating/cooling
equipment not
operating.
Thermostat not
operating.
Remained in customize
mode.
No power to thermostat.
Thermostat mounted
incorrectly on wallplate.
Thermostat is
configured for °F or °C.
The upper or lower
temperature limits were
reached.
Cooling equipment
turns on after delay.
Heating equipment
turns on the fan when
the furnace has
warmed up to a
setpoint.
Corrective Action
Check power to heating/cooling equipment:
— On/Off switch.
— Fuse or circuit breaker.
— Loose 24V connection: at thermostat; at furnace/air
conditioner.
— Incorrect wiring; check appropriate wiring diagram.
Reset System switch.
Wait five minutes.
Check wiring.
Consult equipment manfacturer instructions.
Replace thermostat.
See Customize Your Thermostat section to exit this mode.
Check power to thermostat.
See Mount Thermostat to Wallplate section.
Reconfigure the display. See Customize Your Thermostat
section for instructions to change the display.
Check the temperature setpoints; temperature setting range is
40°F (4°C) to 99°F (37°C).
Wait approximately five minutes after the indicator starts flashing
and then check the registers.
Wait a minute after seeing the on indicator and then check the
registers. If still no heat is coming from the registers, call your
local heating and/or cooling contractor.
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CT500 ELECTRONIC THERMOSTAT
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