Honeywell T8511 Manual page 13

THERMOSTAT
O O W2 O G
T T
2
OUTDOOR
TEMPERATURE
SENSOR
COMPRESSOR
CONTACTOR
FAN
RELAY
COOL
CHANGEOVER
VALVE
AUX. HEAT
RELAY
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
2 AVAILABLE ON SELECT MODELS.
Fig. 16. Typical hookup in heat pump system with
emergency heat relay.
TROUBLESHOOTING GUIDE
Symptom
Display will not come on.
Temperature display is
incorrect.
Temperature settings will
not change. (Example:
Cannot set the heating
higher or the cooling lower.)
Y C E L R
W1
EM. HEAT
RELAY
EQUIPMENT
MONITOR
1
L1
(HOT)
L2
M15092
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.
— If missing 24 Vac:
— If 24 Vac is present, proceed with troubleshooting.
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.
The upper or lower Check the temperature setpoints:
temperature limits were • T8511 heating limits are 40°F to 90°F (7°C to 31°C) and T8501
reached.
• Cooling limits are 48°F to 99°F (9°C to 37°C).
The setpoint Check Installer Setup numbers 34 and 35 and reconfigure the setpoint
temperature range stops.
stops were configured.
T8501 AND T8511 DELUXE ELECTRONIC THERMOSTATS
O O W1
T T
2
OUTDOOR
TEMPERATURE
SENSOR
FAN
RELAY
COOL/HEAT
CHANGEOVER
VALVE
1
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED.
2 AVAILABLE ON SELECT MODELS.
Fig. 17. Typical hookup in heat pump application with
emergency heat relay and O/B terminal.
— 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.
heating limits are 45°F to 88°F
13
THERMOSTAT
O/B G Y1 C E W2
EM. HEAT
RELAY
HEAT
RELAY 2
COMPRESSOR
CONTACTOR
EQUIPMENT
MONITOR
HEAT
RELAY 1
Action
X1 R
1
L1
(HOT)
L2
M4830
(continued)
68-0162—1