York YPAL 060 Definitions, Sequence of Operation, Ventilation Low Ambient Minimum Position Reset

Definitions

“IAQ SENSOR RANGE” –This establishes the span the Simplicity Elite control uses in PPM. 0 PPM would be equal to a 0 volts input to the Simplicity Elite control, “IAQ SENSOR RANGE” would be equal to 10 volts input to the Simplicity Elite control. The “IAQ SENSOR RANGE” must match the PPM range of the sensor installed in the conditioned space.

“IAQ SETPOINT” – This is the conditioned space CO2 level the Simplicity Elite control is trying to maintain.

“MAXIMUM IAQ ECONOMIZER POSITION” – This is the maximum damper position the Simplicity Elite control will allow the damper to open while in a Demand Ventilation mode no matter how great a differential is between the conditioned space CO2 level and the “IAQ SETPOINT”.

Sequence of Operation

The damper will open to the programmed “ECONOMIZER MINIMUM POSITION” whenever the following conditions are met:

•The unit is in the occupied mode.

•There must be a 24-volt output from the Simplic- ity Elite control to the supply fan control circuit. The output is contained at the “FAN” terminal of connector P13 on the Simplicity Elite control board.

•When the economizer becomes active the position of the dampers are controlled by the Economizer PI logic which could move the dampers beyond the “ECONOMIZER MINIMUM POSITION”; however, the Economizer PI logic can never close the dampers less then the “ECONOMIZER MINIMUM POSITION”.

If the above criteria are met, the Simplicity Elite control will then monitor the CO2 level in the conditioned space and vary the position of the outdoor air damper between the “ECONOMIZER MINIMUM POSITION” and the “MAXIMUM IAQ ECONOMIZER POSITION” based on the following:

•The Simplicity Elite control will try to maintain the CO2 level in the conditioned space to +/- 100 PPM of the “IAQ SETPOINT”.

FORM 100.50-NOM6 (1207)

•If the CO2 level in the conditioned space is greater then the “IAQ SETPOINT” + 100 PPM the outdoor air damper will open, but never more than the “MAXIMUM IAQ ECONOMIZER PO- SITION”.

•If the CO2 level in the conditioned space is less then the “IAQ SETPOINT” - 100 PPM the out- door air damper will close, but never less then the “ECONOMIZER MINIMUM POSITION”.

VENTILATION LOW AMBIENT MINIMUM POSITION RESET

This feature allows the control to reset the minimum ventilation set point to a lower value when the outdoor temperature is cold. This assists in keeper the supply air temperature from dropping because of a fixed ventilation requirement when the outdoor temperature drops.

To use this feature the following parameters need to be programmed:

“LOW AMBIENT ECONOMIZER SETPOINT” – this parameter is programmed under the ECONOMIZER/ EXHAUST tab in the Simplicity PC software package.

“LOW AMBIENT ECONOMIZER MINIMUM 5 POSITION” – this parameter is programmed under

the ECONOMIZER/EXHAUST tab in the Simplicity PC software package.

Sequence of Operation

When “LOW AMBIENT ECONOMIZER SETPOINT” is programmed to 0 the feature is disabled. To use this feature programmed this parameter to the outdoor temperature at which you want the Simplicity Elite control to switch to the “LOW AMBIENT “ECONOMIZER MINIMUM POSITION”. This parameter can be programmed between 0 and 60.0° F.

The parameter “LOW AMBIENT ECONOMIZER MINIMUM POSITION” needs to be programmed to the minimum position of the damper when the temperature is below the “LOW AMBIENT ECONOMIZER SETPOINT”. This parameter can be programmed between 0 and 99%. It would normally be programmed less then the “ECONOMIZER MINIMUM POSITION” parameter.

JOHNSON CONTROLS 91