IQ.I.C = 2 (IAQ Discrete Override) — If the user sets IQ.I.C

to 2 (IAQ Discrete Override), and ConfigurationSW.LGIAQ.L is set to OPEN, then an open switch reads low and a closed switch reads high.

If the switch reads low, no action will be taken. If the switch reads high, the economizer will immediately be commanded to the IAQ Economizer Override Position. This can be set from 0 to 100% and can be found at ConfigurationIAQAQ.SPIQ.O.P.

FAN CONTROL FOR THE IAQ DISCRETE INPUT — Under ConfigurationIAQAQ.CF, the IQ.I.F (IAQ Dis- crete Input Fan Configuration) must also be set. There are three configurations for IQ.I.F. Select the configuration which will be used for fan operation. This configuration allows the user to decide (if the supply fan is not already running), whether the IAQ discrete switch will start the fan, and in which state of occupancy the fan will start.

IQ.I.F = 0 Minimum Position Override Switch input will not start fan

IQ.I.F = 1 Minimum Position Override Switch input will start fan in occupied mode only

IQ.I.F = 2 Minimum Position Override Switch input will start fan in both occupied and unoccu- pied modes

IAQ ANALOG INPUT CONFIGURATION — This input is an analog input located on the main base board (MBB). There are 4 different functions for this input. The location of this con- figuration is at ConfigurationIAQAQ.CFIQ.A.C.

The functions possible for IQ.A.C are:

0 = no IAQ analog input

1 = IAQ analog input

2 = IAQ analog input used to override to a set position

3 = 4 to 20 mA 0 to 100% economizer minimum position control

4 = 0 to 10 kilo-ohms 0 to 100% economizer minimum position control

Options 2, 3, and 4 are dedicated for third party control. IQ.A.C = 2 (IAQ Analog Input Used to Override) — Under ConfigurationIAQAQ.SP, set IQ.O.P (IAQ Economizer Override Position). The IQ.O.P configuration is adjustable from 0 to 100%. These configurations are also used in conjunc- tion with ConfigurationIAQAQ.CFIQ.A.F (IAQ 4 to 20 mA Fan Configuration). There are three configurations for IQ.A.F and they follow the same logic as for the discrete input. This configuration allows the user to decide (if the supply fan is not already running), if the IAQ Analog Minimum Position Override input will start the fan, and in which state of occupan- cy the fan will start.

IQ.A.F = 0 IAQ analog sensor input cannot start the supply fan

IQ.A.F = 1 IAQ analog sensor input can start the supply fan in occupied mode only

IQ.A.F = 2 IAQ analog sensor input can start the supply fan in both occupied and unoccupied modes

If IQ.A.F is configured to request the supply fan, then configurations D.F.ON and D.F.OF need to be set. These configuration settings are located under ConfigurationIAQAQ.SP and configure the fan override operation based on the differential air quality (DAQ). If DAQ rises above D.F.ON, the control will request the fan on until DAQ falls be- low D.F.OF.

NOTE: If D.F.ON is configured below DAQ.H, the unit is in occupied mode, and the fan was off, then DAQ rose above D.F.ON and the fan came on, the economizer will go to the economizer minimum position (EC.MN).

The 4 to 20 mA signal from the sensor wired to TB5-6 and 7 is scaled to an equivalent indoor CO2 (IAQ) by the parame- ters IQ.R.L and IQ.R.H located under the Configuration IAQAQ.S.R menu. The parameters are defined such that 4 mA = IQ.R.L and 20 mA = IQ.R.H. When the differential air quality DAQ (IAQ – OAQ.U) exceeds the DAQ.H set point (ConfigurationIAQAQ.SP menu) and the supply fan is on, the economizer minimum vent position (Configuration IAQDCV.CEC.MN) is overridden and the damper is moved to the IQ.P.O configuration. When the DAQ falls below the DAQ.L set point (ConfigurationIAQAQ.SP menu), the economizer damper is moved back to the minimum vent position (EC.MN).

NOTE: Configuration OAQ.U is used in the calculation of the trip point for override and can be found under Configura- tionIAQAQ.SP.

IQ.A.C = 3 (4 to 20 mA Damper Control) — This configura- tion will provide full 4 to 20 mA remotely controlled analog in- put for economizer minimum damper position. The 4 to 20 mA signal is connected to terminals TB5-6 and 7. The input is processed as 4 mA = 0% and 20 mA = 100%, thereby giving complete range control of the effective minimum position.

The economizer sequences can be disabled by setting Con- figurationECONE.SEL to 0. Complete control of the economizer damper position is then possible by using a 4 to 20 mA economizer minimum position control or a 0 to 10 kilo-ohm 0 to 100% economizer minimum position control via configuration decisions at ConfigurationIAQAQ.CF IQ.A.C.

IQ.A.C = 4 (10 Kilo-ohm Potentiometer Damper Control)

This configuration will provide input for a 10 kilo-ohm lin- ear potentiometer that acts as a remotely controlled analog in- put for economizer minimum damper position. The input is processed as 0 ohms = 0% and 10,000 ohms = 100%, thereby giving complete range control of the effective minimum position.

CONTROLS OPERATION

Modes — The ComfortLink™ controls operate under a hierarchy of command structure as defined by three essential elements: the System mode, the HVAC mode and the Control mode. The System mode is the top level mode that defines three essential states for the control system: OFF, RUN and TEST.

The HVAC mode is the functional level underneath the System mode which further defines the operation of the control. The mode selection process is shown in Appendix D.

The Control mode is essentially the control type of the unit (ConfigurationUNITC.TYP). This defines from where the control looks to establish a cooling or heating mode and whether 2 stages or multiple stages of cooling capacity opera- tion are controlled.

Furthermore, there are a number of modes which operate concurrently when the unit is running. The operating modes of the control are located at the local displays under Operating Modes. See Table 42.

Currently Occupied (OCC) — This variable displays the cur- rent occupied state of the unit.

Timed Override in Effect (T.OVR) — This variable displays if the state of occupancy is currently occupied due to an override.

DCV Resetting Minimum Position (DCV) — This variable displays if the economizer position has been lowered from its maximum vent position.

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Carrier 48/50AJ specifications Controls Operation