Greenheck Fan 470656 manual Start-Up- Economizer optional, Verify Sensor Installation

Start-Up - Economizer (optional)

Note

To prevent premature heat exchanger failure, do not locate units where chlorinated, halogenated, or acid vapors are present.

Note

Units with an economizer are designed for either 0-30% outside air (HV-1), 31-75% outside air (HV‑2) or 100% return air (HV-3). Refer to the CAPS submittal for the unit’s ventilation type.

Note

HV-1 and HV-2 use economizer controls (EC) or (MB).

Note

Economizer control may use outside air temperature reference (EC-1), outside enthalpy reference (EC‑2), differential temperature reference (EC-3) or differential temperature reference (EC-4).

Note

Economizer control may use a potentiometer (MB‑1), 2-10 VDC signal (MB-2), 4-20mA signal (MB‑3) or a manual quadrant (MB-4).

1. Verify Sensor Installation

All economizer options (EC) require an outdoor air temperature or enthalpy sensor to be field-installed inside of the weatherhood and field-wired to terminals SO+ and SO- on the economizer.

Economizer options EC-3 and EC-4 require an outdoor air temperature or enthalpy sensor to be field-installed in the return air duct and field-wired to terminals SR+ and SR- on the economizer.

Verify that all economizer sensors needed for your application are properly installed and wired.

2. Set Minimum Outside Air

Set the minimum outside air position. HV-1 is designed for 0-30% outside air and HV-2 is designed for 31-75% outside air.

All economizer options, EC-1, EC-2, EC-3 and EC-4 and option MB-1 use a potentiometer to set the minimum outside air damper position.

The potentiometer is located on the economizer for options EC-1, EC-2, EC-3 and EC-4. The potentiometer may be factory-mounted in the unit control center or field-mounted in the space for option MB-1.

MB-2 and MB-3 use an external signal from a building management system to position the dampers.

MB-4 uses a manual quadrant located on the inlet damper to position the dampers.

32Model IG / IGX Make-Up Air

important

The outside air volume must be measured and compared to the total air volume when setting the minimum outside air. The minimum outside air should never be set based on the inlet damper or potentiometer position.

3.Set the Enthalpy Changeover Set Point (optional)

If using an economizer, the enthalpy changeover setting must be set. If differential temperature or differential enthalpy control is used, set the enthalpy changeover set point to D. If outside air temperature or enthalpy reference is used, set the enthalpy changeover set point to the desired setting from the following table.

Enthalpy Changeover Setting

Setting	Changeover
	Temperature* (°F)
A	73
B	70
C	67
D	63

*Temperature at 50% relative humidity, see the Honeywell W7212 Economizer instructions for set points at other humidities

Note

For options EC-3 and EC-4 the enthalpy changeover set point is the temperature at which the economizer will send the dampers to the minimum outside air position.

4. Program Optional Room Stat

Program the optional room stat. Separate detailed instructions for programming the room stat ship with the optional room stat.

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