Wiring Diagram (Fig. 14); Troubleshooting Guide - Honeywell T8524 Deluxe Product Data

T8524 DELUXE ELECTRONIC THERMOSTAT
Minimum-Off Timing
A minimum-off timer assures that the cooling compressor or
heat pump compressor does not come on again for at least
five minutes after it turns off. The minimum-off timer is
triggered when the compressor goes off and when the
system switch is changed. If he compressor turns off when
the setpoint is changed, then the minimum-off timer is
triggered. The minimum-off timer operates during the first
stage of both heating and cooling on the heat pump
thermostat models and cooling only on the standard
application models.
Fan Control
The fan will be on when any of these conditions are present
(it can take up to 20 seconds for the fan to turn on).
Fan On: This setting means that the fan is energized
continuously.
Fan Auto: The Auto setting means the fan will run only
with the heating and cooling system.
Select models allow the installer the option of electric or
conventional heat fan operation in the installer setup. When
set for electric heat systems, the fan comes on at the same
time as the heat and is energized by the thermostat. The fan
is energized by the plenum switch when set for conventional
heating system.
Outdoor Temperature Sensor (select models)
The outdoor temperature sensor is used to display the
outdoor temperature. Pressing the Information i
will show the outdoor temperature if installer setup number 24
is set to 1.

TROUBLESHOOTING GUIDE

Symptom
Display will not come on.
Temperature display is
incorrect.
68-0202
key once
Possible Cause
Thermostat is not being • Check that C terminal is connected to the system transformer.
powered. • Check for 24 Vac between C and R or RH terminals.
Room temperature Enter Installer Setup number 37 and reconfigure the display.
display has been
reconfigured.
Thermostat is Enter Installer Setup number 14 and reconfigure the display.
configured for °F or °C
display (select models).
Bad thermostat location. Relocate the thermostat.

WIRING DIAGRAM (Fig. 14)

O
RC Y1 G
2
FAN
RELAY
COOL
COMPRESSOR
DAMPER
CONTACTOR 1
3
L1
(HOT)
L2
1
COOLING
TRANSFORMER
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
2
JUMPER RC TERMINAL TO R TERMINAL WHEN INSTALLED ON A
ONE TRANSFORMER SYSTEM.
3 CAN BE USED FOR CHANGEOVER VALVE ON HEAT
PUMP SYSTEMS.
Fig. 14. Typical hookup in multistage
heating and cooling application.
— If missing 24 Vac:
— check if the circuit breaker is tripped—reset the
circuit breaker.
— check if the system fuse is blown—replace the fuse.
— check if the power switch on the HVAC equipment is
in the Off position—set to the On position.
— check wiring between thermostat and HVAC
equipment—replace any broken wires and tighten
any loose connections.
— If 24 Vac is present, proceed with troubleshooting.
12
THERMOSTAT
Y2 C B W2 W1 R
HEAT
COMPRESSOR
RELAY
CONTACTOR 2
2
HEAT HEAT
DAMPER RELAY
1
3
HEATING
TRANSFORMER
Action
OT OT
OUTDOOR
SENSOR
1
L1
(HOT)
L2
M11309
(continued)