Greenheck IG / IGX (464104 IOM) (Pre-2009) - Manual (Page 47)

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Start-Up
Start-Up - Mixing Box (Optional)
Step 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 mixing box 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.
Step 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.
NOTE!
Units with a mixing box 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 mixing box controls (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).
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.
NOTE!
Mixing box control may use a potentiometer (MB-1), 2-10VDC signal (MB-2), 4-20mA signal (MB-3) or a
manual quadrant (MB-4).
NOTE!
To prevent premature heat exchanger failure, do not locate units where chlorinated, halogenated, or
acid vapors are present.