Installation
Table 11. (Q667) Switching Subbase
Subbase Switch Positions | Check Continuity between These | Circuit should | |
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Fan | System | Terminal Pairs | be |
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ON | N/A | 9 (Subbase) & 10 (Subbase) | Closed |
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| 9 (Subbase) & 10 (Subbase) | Open |
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AUTO | OFF | 5 (Subbase) & 5 (T’stat) | Open |
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| 4 (Subbase) & 4(T’Stat) | Open |
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| 9 (Subbase) & 10 (Subbase) | Open |
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AUTO | HEAT | 5 (Subbase) & 5 (T’stat) | Closed |
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| 4 (Subbase) & 4(T’Stat) | Open |
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| 9 (Subbase) & 10 (Subbase) | Closed |
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AUTO | AUTO | 5 (Subbase) & 5 (T’stat) | Closed |
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| 4 (Subbase) & 4(T’Stat) | Closed |
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| 9 (Subbase) & 10 (Subbase) | Closed |
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AUTO | COOL | 5 (Subbase) & 5 (T’stat) | Open |
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| 4 (Subbase) & 4(T’Stat) | Closed |
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Discharge Air Sensor (Honeywell 6RT1)
A discharge air sensor ships with each unit when the constant volume control option is ordered. The sensor should be installed in a turbulent free area of the discharge air duct at a location that will provide accurate supply air sensing. Refer to the illustration in Figure 33 for installation and sensor dimensional information.
WARNING
Hazardous Voltage!
Disconnect all electric power, including remote disconnects before servicing. Follow proper lockout/tagout procedures to ensure the power can not be inadvertently energized. Failure to disconnect power before servicing could result in death or serious injury.
Wire the sensor in accordance with the field connection diagram in Figure 32. As shipped form the factory, a resistor (7R1) is installed on terminal board 1TB8 terminals 5 & 6). Remove this resistor when the sensor is installed. Shielded cable (Belden 8760 or equivalent) must be used when wiring the sensor to the terminal board inside the unit’s control panel.
When the sensor is installed, it serves two functions;
1.It sends the supply air temperature to the master energy controller (MEC), in the form of an analog input, to assist in the rate at which the system changes the space temperature. By offsetting the actual zone thermostat setpoint, up or down, the MEC can closer control the zone comfort level.
2.It serves as a low limit for the system when the supply air temperature reaches too high a delta tee between the actual supply air temperature and the zone temperature to help prevent overshooting of the zone thermostat setpoint.
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