Unit Status And Defrost Output Or Tair Setpoint Status; Sanitary Water Input And 3 Way Valve Output; Water Pump On / Off Management; Additional Water Pump On / Off Management - Carrier 30AWH004HB Service Manual

Unit Status and Defrost output or Tair Setpoint status

Based on the NUI code 147 set-up, the Output J7 Pin 2 (N-5 on the terminal block) could play for one of these Functions:
- ALARM: The intent of this output is to point out the alarm condition. This signal could be
used by an external control to verify if the Unit is able to operate with the requested function.
- Tair SETPOINT STATUS: The intent of this output is to give signal to a potential Fan Coil System when the T ambient
set-up measured by the NUI is reached. A hysteresis of +1°C / – 1°C is used. This signal could be used like a window
contact by the Fan Coil to stop the fans and/or the water valves.

Sanitary water Input and 3 Way Valve Output

The combination of the Sanitary Water Inputs and Outputs should be able to manage an external Sanitary Water Boiler
and this is the logic that is driving this function:
- When an external Sanitary Water Boiler needs hot water from the units, it close the dry contact Pins 13-15 on the
terminal block.
- The routing that is always running in order to verify Input changes detect this need and the unit mode, whichever
it is the current status, become in HEAT mode at the max allowed WSP admitted as per the Enveloped Limitation
protection.
- In case of no alarm or defrost is active, the 3 Way Valve Output (pins N-10-18 on terminal block) become ON while, vice
versa, this output is always OFF in case of alarm and/or Defrost
- In addition, the NUI, if available, will display the relative Icon.
or Cool Mode the SHW logic is always actives.
NOTE: when SHW is ON, EHS is always OFF

Water Pump On / Off Management

The water pump should be always ON apart if any alarms are active or if the unit is in OFF mode (selected or forced by the
unit itself ).
When the system turn OFF the water pump must be ON for additional 30 seconds.
for few seconds increases the life time of the pump.
If OAT < temperature set in code 148
The main water pump activation depending by the code 155 (0. always ON, 1. always OFF or 2. ON/ OFF depending by
EHS)

Additional water Pump On / Off Management

The management for the additional water pump, linked to the pin 12 on the X and H terminal block, is the following:
If OAT > temperature set in code 148
The additional water pump activation depending by the code 156
If OAT < temperature set in code 148
The additional water pump activation depending by the code 157 (0. always ON, 1. always OFF or 2. ON/ OFF depending
by EHS)
Flow Switch Protection
- If flow switch contact is open (no water flow) Unit and WP turn OFF.
- The system retries to start for 5 times before displaying alarm.
The compressor is allowed to turn on if requested to when the water is flowing through the heat exchanger (flow switch
contact OFF) and timeguard has expired.
SM_30AW.indd 61
Control management
61
5
NUI code 147
SHW: Sanitary
Hot Water
EHS: External
Heat Source
WSP: water set-point
NUI code 153
SHW: Sanitary
Hot Water
EHS: External
Heat Source
NUI codes 148,
155
SHW: Sanitary
Hot Water
EHS: External
Heat Source
WP: Water
Pump
ADD WP:
Additional
Water Pump
NUI codes 148,
156, 157
Settings:
Size 4kW = 300 l/h
Other Sizes = 420 l/h
30AW
14-03-2011 14:45:07