The enthalpy control receives the outdoor air enthalpy from the outdoor air enthalpy sensor and provides a dry contact switch input to the PremierLink controller. A closed contact indicates that outside air is preferred to the return air. An open contact indicates that the economizer should remain at minimum position.
Differential Enthalpy Control — Differential enthalpy control is provided by sensing and comparing the outside air and return air enthalpy conditions. Install the outdoor air enthalpy control as described above. Add and install a return air enthalpy sensor.
Return Air Enthalpy Sensor — Mount the
levels. This information is used to monitor IAQ levels. Several types of sensors are available, for wall mounting in the space or in return duct, with and without LCD display, and in combination with space temperature sensors. Sensors use infrared technology to measure the levels of CO2 present in the space air.
The CO2 sensors are all factory set for a range of 0 to 2000 ppm and a linear mA output of 4 to 20. Refer to the instructions supplied with the CO2 sensor for electrical requirements and terminal locations. See Fig. 43 for typical CO2 sensor wiring schematic.
ENTHALPY CONTROLLER | RED |
| S (OUTDOOR | ||||
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| + | AIR | |
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| BRN |
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| B C | TR | TR1 | BLK | ENTHALPY | ||
A |
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| SENSOR) | ||||
| D | SO | + |
| RED |
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| SR | + |
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| S (RETURN AIR | |
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| + | ENTHALPY |
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| 2 | 3 |
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| SENSOR) |
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| 1 |
| GRAY/ORN |
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| LED |
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| WIRE HARNESS | |
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| GRAY/RED | IN UNIT |
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NOTES:
1.Remove
2.Switches shown in high outdoor air enthalpy state. Terminals 2 and 3 close on low outdoor air enthalpy relative to indoor air enthalpy.
3.Remove sensor mounted on back of control and locate in outside air- stream.
C06019
H G 24 VAC OR
+ - 24 VDC
50TC
+
- SIG COM
NC }ALARM
COM RELAY
NO CONTACTS
2 1 8 7 6 5 4 3 2 1
C07134
Fig. 42 - Outside and Return Air Enthalpy Sensor
Wiring
To wire the return air enthalpy sensor, perform the following:
1.Use a
2.At the enthalpy control remove the
3.Connect the
NOTE: The enthalpy control must be set to the “D” setting for differential enthalpy control to work properly.
The enthalpy control receives the indoor and return enthalpy from the outdoor and return air enthalpy sensors and provides a dry contact switch input to the PremierLink controller. A closed contact indicates that outside air is preferred to the return air. An open contact indicates that the economizer should remain at minimum position.
Indoor Air Quality (CO2 sensor) — The indoor air quality sensor accessory monitors space carbon dioxide (CO2)
Fig. 43 - Indoor/Outdoor Air Quality (CO2) Sensor
(33ZCSENCO2) - Typical Wiring Diagram
To accurately monitor the quality of the air in the conditioned air space, locate the sensor near a
Do not mount the IAQ sensor in drafty areas such as near supply ducts, open windows, fans, or over heat sources. Allow at least 3 ft (0.9 m) between the sensor and any corner. Avoid mounting the sensor where it is influenced by the supply air; the sensor gives inaccurate readings if the supply air is blown directly onto the sensor or if the supply air does not have a chance to mix with the room air before it is drawn into the return airstream.
Wiring the Indoor Air Quality Sensor —
For each sensor, use two
To connect the sensor to the control, identify the positive (4 to 20 mA) and ground (SIG COM) terminals on the sensor. See Fig. 43. Connect the
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