Technical Specifications
Thermostat Type
Electronic programmable thermostat for 2−Stage (gas or electric)
Table 5
51M39 Terminal Designations
Terminal Description
R24VAC
Y1 | |
|
|
W1 | |
|
|
Y2 | |
|
|
W2 |
GFan control
LService Indicator
C24VAC common
TOutdoor temperature sensor connection 1
TOutdoor temperature sensor connection 2
Power Supply Range
18VAC − 30VAC (24VAC nominal), 60Hz
CAUTION
24VAC is present on the terminals of the thermostat bracket. If removing the thermostat from the wall, use caution and avoid touching any of the connec- tor terminals on the wall bracket.
Also, when working with the thermostat dip switches, use a non−conductive tool and take cau- tion to avoid making any contact with the circuit board, its imprinted circuitry and its connector prongs.
Temperature Display
Display Scale: Fahrenheit or Celsius user selectable (via DIP switch; see figure 18)
| Changing Fahrenheit/Celsius Setting |
1 |
|
2 |
|
3 |
|
4 |
|
5 |
|
6 | PLUG IN (Use Care To Avoid Bending Prongs.) |
7 |
|
| F/C (Fahrenheit/Celsius) switch |
| shown in Celsius position |
Figure 18
Display range: 35°F (2°C) to 99°F (37°C)
Display resolution: 1°F (1°C)
Display Accuracy: +/−1°F
If the Fahrenheit/Celsius display must be changed, use a plastic, non−conductive tool to push the dip switch to the right position (see figure 18).
Indoor Temperature Measurement Range
Measurement Scale: Fahrenheit
Measurement Range: 35°F to 99°F
Measurement Resolution: 0.5°F
Measurement Accuracy: +/−1°F
Field Offset: via DIP switches to +/−3°F
Sampling Method: temperature measurements sampled every 15 seconds. Displayed temperature is the average of the last four measurements.
Outdoor Temperature Measurement Range
Measurement Scale: Fahrenheit
Measurement Range: −22°F to 122°F
Measurement Resolution: 1°F
Measurement Accuracy: +/−2°F
Temperature Setpoint Range
Setting range: 50°F (10°C) to 90°F (32°C)
Setting resolution: 1°F (1°C)
Smart Setback Recovery (via DIP switch #6)
Smart Setback Recovery (SSR) affects the way the ther- mostat responds to program events. If SSR is disabled, the thermostat will react to a program event at the time the event occurs. However, if SSR is enabled, the thermostat will react to a program event before the event occurs such that the desired temperature is reached at the time of the event, not after.
Autochangeover Deadband Selection (via DIP switch #7)
Autochangeover deadband can be set to 4 or 6 degrees. When autochangeover is enabled (via the AUTO button), the thermostat will automatically change over from heating to cooling and vice versa, to keep the room temperature in between the heating and cooling setpoints. The deadband is the minimum difference between the heating and cooling setpoints.
Fan Control
AUTO or ON modes, gas or electric heat compatible via DIP switches (also see Thermostat Output section).
I/O Relays
All thermostat relays are latching type to minimize power consumption.
Equipment Protection Timers
Minimum Compressor OFF time: 5 minutes
Minimum Compressor ON time: 4 minutes
Minimum Furnace ON time: 3 minutes
Minimum furnace cycle time (elapsed time between any furnace activation and the next furnace activation): 6 min- utes.
Minimum elapsed time between any compressor activa- tion and the next compressor activation: 6 minutes.
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