COOL − Using the Cool Mode
Enabling and Disabling Cool Mode
Use the COOL button to enable or disable cool mode as desired. If the thermostat is in heat or off mode, cool mode is enabled when the COOL button is pressed. This is indi- cated by COOL on the right side of the display (see figure 9).
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| Turn Cool ON/OFF |
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| Heat | Cool |
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| Prog | Auto |
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| i0:30 |
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| 70 | Copy Day/Time |
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75 | 66 | Fan | Hold | (DOOR |
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| OPEN) |
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| Settings Enter |
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| (Outside) |
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Figure 9
If the thermostat is in cool mode, pressing the COOL but- ton disables cool mode (indicated by OFF on the right side of the display).
Cooling Demand
Set the thermostat to cool mode to control the cooling equipment. Then, if the room temperature is higher than the temperature setpoint, as shown in figure 10, the ther- mostat detects a cooling demand and will activate the cool- ing equipment to satisfy the demand.
Cooling Demand
| COOL SETPOINT |
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FAN | 76° |
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AUTO | COOL | ||
ROOM |
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° HEAT SETPOINT | Lo | ||
80 | 68 | ° | |
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| Hi |
Figure 10
Cooling operation is indicated by flashing nowflake" icons. When the actual temperature drops below the tem- perature setpoint, the snowflake icons will disappear. This indicates that the cooling demand has been satisfied and that the cooling equipment has been turned off.
If your system supports 2−stage cooling (as does the 51M42 thermostat), you may notice various cooling levels being delivered during a demand. Also, if a small cooling demand is present, "Lo" will be displayed in the SYSTEM box. However, if a large cooling demand is present, "Hi" will be displayed in the lower right side of the display (shown in figure 10).
NOTE − If no buttons are pressed during a demand for cooling, the equipment must operate for at least 4 minutes. After a demand has been satisfied, cooling equipment op- eration is locked out for 5 minutes. If another cooling de- mand occurs during this 5−minute interval,
snowflakes will flash; however, the cooling equipment will not operate until the 5−minute delay has elapsed.
AUTO − Using the Autochangeover Mode
When in either heat mode or cool mode, autochangeover can be enabled or disabled by pressing the AUTO button. If enabled, AUTO appears at the lower right corner of the dis- play. The thermostat will then automatically change over from heating to cooling and vice versa, to keep the room temperature in between the heating and cooling setpoints. Autochangeover can be used in either of the thermostat hold modes, or when the thermostat program is running. These modes are described later.
HOLD − Using Temperature Hold Modes
When the HOLD button is displayed at the HOME screen, the thermostat is in a temperature hold condition. This means that the temperature program data is ignored and the thermostat functions much like a non−programmable thermostat.
Adjusting Temperature Setpoint in Hold Mode
The temperature setpoint represents the desired tempera- ture of the space around the thermostat. The default heat setpoint in hold mode is 70°F; the default cool setpoint in hold mode is 78°F.
To adjust the setpoint, press the UP or DOWN (YB) arrow buttons (see figure 11); the existing setpoint is displayed to the right of the actual room temperature. Each button press adjusts the setpoint up or down by 1 degree.
| Hold Temperature Mode |
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| Heat | Cool |
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| i0:30 | Prog | Auto |
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| 78 | Copy Day/Time |
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80 | 70 | Fan | Hold | (DOOR |
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| OPEN) |
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| Settings Enter |
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| (Outside) |
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Figure 11
After the desired setpoint is reached, the HOME screen will reappear after about 15 seconds.
Permanent Hold Mode
At any time the program is running, from the HOME screen, set a permanent hold (program override) by press- ing the HOLD button (see figure 11). The thermostat now functions much like a non−programmable thermostat. Use the Up/Down arrow buttons to adjust the hold setpoint. To return to the program, press the HOLD button again.
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