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Carrier 50HCQ04---12 User Manual

Page 14

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14

Dehumidification Test

For units with the factory Reheat option, the

dehumidification relay is used to change the output status

to operate the circuits in different Reheat modes.

Dehumidification relay on by itself puts all circuits

running in Hot Gas Reheat dehumidification mode;

dehumidification relay on and the cooling test

(compressor test relays) on puts unit and or individual

circuits in subcooling dehumidification mode. The fans

and heating service test outputs are reset to “Disable” for

the dehumidification service test. Indoor and outdoor fans

are controlled normally to maintain proper unit operation.

All normal cooling/dehum alarms and alerts are

functional.

Power Exhaust Test

This point allows the board’s power exhaust (PE) output

to be manually turned On (Enable) and Off (Disable).

Power Exhaust test can operate simultaneously with other

Service Test Points.

Economizer Test

This point allows the board’s economizer output to be

manually controlled from 0 to 100 % Open. Economizer

test can operate simultaneously with other Service Test

Points.

Analog Output 2 Test

This test point activates the AO2 0-10vdc analog output at

J22. These rooftops do not use this output, therefore this

test is not used.
NOTE: Service Test Mode does not timeout. Be sure to
turn off test mode or cycle power to the RTU to return to
normal operation.

Configuration

The RTU-OPEN controller’s configuration points effect

the unit’s inputs and operation. Review and understand

the meaning and purpose of each configuration point

before changing it from the factory default value. Use the

RTU-OPEN Start-up Sheet during configuration; fill in

changed values if changed from factory default. There are

three main configurations menus: SETPOINT, UNIT, and

SERVICE. Each configuration point is described below

under its according menu. See Appendix A for BACview

menu structure.

Setpoint

Occupied Heating Setpoint -- The heating setpoint the

controller maintains during the occupied period.

Range = 40-90_F

Occupied Cooling Setpoint – The cooling setpoint the

controller maintains during the occupied period.

Range = 55-99_F

Unoccupied Heating Setpoint – The heating setpoint the

controller maintains during the unoccupied period.

Range = 40-90_F

Unoccupied Cooling Setpoint – The cooling setpoint the

controller maintains during the unoccupied period.

Range = 55-99_F

Effective Heating Setpoint – The current setpoint value

heating operation will control to.

Effective Cooling Setpoint – The current setpoint value

cooling operation will control to.
Optimal Start - The earliest time prior to occupancy, at

which the Optimal Start function may begin to adjust the

effective setpoints. Setting this to 0 will disable optimal

start.

Range = 0-4 hours

Default = 4 hours

Occ Relative Humidity Setpoint – The space RH

setpoint the controller maintains during the occupied

period.

Range = 0 to the Unocc RH setpoint

Default 60%

Unocc Relative Humidity Setpoint – The space RH

setpoint the controller will maintain during the

unoccupied period.

Range = 30-100%

Default = 90%

DCV Max Ctrl Setpoint – The difference between indoor

and outdoor CO

2

level which results in maximum

ventilation damper position.

Range = 0-9999ppm Default = 650ppm

Power Exhaust Setpoint – When the economizer damper

position opens above this point the power exhaust

operation will begin. When the damper position falls

below this point and 5% lower the power exhaust will

shutdown.

Range = 20-90%

Default = 50%

NOTE:

This point is only used when Continuous

Occupied Exhaust = NO

Unit

Fan Mode – Sets the operation of the indoor fan when not

in cooling or heating mode. Refer to fan operation for

details on each operation.

Range = Auto, Continuous, or Always On

Default = Continuous

Unit Start Delay – Refers to the time delay the unit will

wait after power up or when transitioning from

unoccupied to occupied before it pursues any specific

operation.

Range = 0-30 sec

Default = 5 sec

Fan Off Delay – Time delay in which the fan will

continue run after being commanded off.

Range = 0-180sec

Default = 90sec

Minimum Cooling SAT – The supply air temperature

must remain above this value to allow cooling with the

economizer and/or compressors. There is 5_F plus and

minus deadband to this point. If the SAT falls below this

value during cooling a compressor stage will be removed

and/or the economizer will return to minimum position.

Range = 45-70_F

Default = 50_F

Maximum Heating SAT – The supply air temperature

must remain below this value to allow heating. There is

5_F plus and minus deadband to this point. If the SAT

falls below this value during heating the heat stages will

begin to decrease until the SAT has dropped below this

value.

Range = 95-150_F

Default = 120_F

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