7 TROUBLESHOOTING cont .
8 WIRING DIAGRAMS
Typical Carrier, Bryant, Payne, Day & Night and Reliant Heat Pumps
SYMPTOM
LO is shown in the thermostat display where the room temperature is normally displayed.
Thermostat will not allow me to program
asetpoint temperature lower than 45˚ F (7˚ C).
Fan continues to run all the time whether the system is on or off.
Fan continues to run in cooling mode when the system has turned off.
The room is too warm or too cold.
POTENTIAL SOLUTION
The temperature sensed by the thermostat is lower than the 40˚ F (5˚ C) lower limit of the thermostats display range. The display will return to normal after the sensed temperature rises within the 40˚ to 99˚ F (5˚ to 37˚ C) display range. If the temperature in the controlled space seems to be normal, wait for the thermostat to acclimate to the correct room temperature. If the room seems to be colder than usual, turn on the heating system to raise the temperature as needed for comfort within the room.
This condition could occur from the system being turned off during a cold weather period or upon installation when the thermostat has been stored for a long period of time in a cold vehicle or location prior to being installed. The thermostat should be allowed to warm up prior to installation to allow proper heating control once installed.
This is below the normal thermostat temperature setting range of 45˚ to 90˚ F (7˚ to 32˚ C).
Check that the fan control switch is in the AUTO position. This will allow the fan to run only when the heating or cooling system is turned on and running.
Check thermostat wiring to make sure that the fan control wiring is connected to the correct terminals on the wiring terminal block. See Installation and Wiring Diagrams sections of this manual.
The Residual Cooling Fan Control Feature can allow up to a 90 second fan delay after cooling system shutdown for energy efficiency gains. The default setting is 60 seconds. This can be changed to disable this feature or shorten the time period if desired. See Setting Residual Cooling Fan Feature section of this manual.
See Review Set Temperature section of this manual to verify the current setpoint and make any modifications that are necessary.
THERMOSTAT TERMINAL BLOCK
R | Y1 | Y2 | W2 | E | G | O | B | L | C |
| R | |
| Y | |
PCB | W2 | |
E | ||
PUMP | ||
G | ||
HEAT | ||
O | ||
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| L or X | |
| C |
Typical Coleman, Rheem and Ruud Heat Pumps
THERMOSTAT TERMINAL BLOCK
R Y1 Y2 W2 E G O B L C
| R | |||
| Y | |||
PCB | W2 | |||
E |
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PUMP |
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G | ||||
HEAT | ||||
B | ||||
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| L | |||
| X | |||
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Typical Comfortmaker and
THERMOSTAT TERMINAL BLOCK
| R | Y1 Y2 W2 E | G | O | B | L | C |
| R | User |
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| Y | Supplied |
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PCB | W1 |
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G |
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PUMP |
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O |
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HEAT |
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C |
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| W2 | CAPPED |
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| X | CAPPED |
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16 | 17 |