Check Thermostat Operation; Fan Operation; Heating System; Cooling System - White Rodgers 1F78 User Manual

MOUNTING AND WIRING
4
CONTINUED FROM SECOND PAGE
Y
B O
NOTE
For 2-wire Heat only,
attach to RH and W
Figure 2. Typical wiring diagram for
heat only, 3-wire, single transformer systems
B O
Cooling
System
Figure 3. Typical wiring diagram for
cool only, 3-wire, single transformer systems
NOTE
RED jumper wire (provided with thermostat) must be
connected between thermostat RH and RC terminals
for proper thermostat operation with this system.
B O
Cooling
System
Figure 4. Typical wiring diagram for
heat/cool, 4-wire, single transformer systems
5

CHECK THERMOSTAT OPERATION

To prevent static discharge problems, touch side of ther-
mostat to release static build-up before touching any keys.
If at any time during testing your system does not operate
properly, contact a qualified serviceperson.

Fan Operation

If your system does not have a G terminal connection, skip to

Heating System.

1. Turn on power to the system.
2. Move FAN switch to ON position. The blower should begin to
operate.
3. Move FAN switch to AUTO position. The blower should stop
immediately.

Cooling System

!
To prevent compressor and/or property damage, if the
outdoor temperature is below 50 F, DO NOT operate the
cooling system.
JUMPER
WIRE
THERMOSTAT
G W RC RH
SYSTEM
Fan Heating
Relay System
24 VAC
TRANSFORMER
JUMPER
WIRE
THERMOSTAT
Y
G W RC RH
SYSTEM
Fan
Relay
Hot
24 VAC 120 VAC
Neutral
TRANSFORMER
JUMPER
WIRE
THERMOSTAT
Y
G W RC RH
SYSTEM
Fan Heating
Relay System
Hot
24 VAC
Neutral
TRANSFORMER
NOTE
CAUTION
Hot
120 VAC
Neutral
Figure 6. Typical wiring diagram for heat pump
120 VAC
Figure 7. Typical wiring diagram for heat pump
This thermostat has a time delay between cooling cycles to allow
the head pressure in the compressor to stabilize. If the tempera-
ture is adjusted to call for cool within 5 minutes of the last cycle the
snowflake icon will blink indicating the thermostat is locked out.
After 3 to 5 minutes, the compressor will start and the snowflake
icon will stop flashing. This helps prevent the compressor from
cycling too quickly and is normal operation for the thermostat.
1. Move SYSTEM switch to COOL position.
2. Press
ture. The blower should come on immediately on high speed,
followed by cold air circulation
3. Press
perature. The cooling system should stop operating.
1. Move SYSTEM switch to HEAT position. If the heating system
has a standing pilot, be sure to light it.
2. Press
ture. The heating system should begin to operate.
3. Press
perature. The heating system should stop operating.
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B O Y G W RC
Cooling Fan Heating
System Relay System
Figure 5. Typical wiring diagram for
heat/cool, 5-wire, two-transformer systems
JUMPER
WIRE
B O Y G W
Reversing Compressor Fan
Valve* Contactor Relay
* Reversing valve is energized when the
system switch is in the COOL position
with reversing valve energized in COOL
JUMPER
WIRE
B O Y G W
Reversing Compressor Fan
Valve* Contactor Relay
* Reversing valve is energized when the
system switch is in the HEAT position
with reversing valve energized in HEAT
to adjust thermostat setting below room tempera-
to adjust temperature setting above room tem-
Heating System
to adjust thermostat setting above room tempera-
to adjust temperature setting below room tem-
THERMOSTAT
RH
SYSTEM
Hot
24 VAC
120 VAC
Neutral
HEATING
TRANSFORMER
Hot
24 VAC
120 VAC
Neutral
COOLING TRANSFORMER
JUMPER
WIRE
THERMOSTAT
RC RH
SYSTEM
Hot
24 VAC 120 VAC
Neutral
TRANSFORMER
JUMPER
WIRE
THERMOSTAT
RC RH
SYSTEM
Hot
24 VAC
120 VAC
Neutral
TRANSFORMER