Backup External Heat Source Functionality - Carrier 30AWH004HB Service Manual

Backup External Heat Source functionality (X and H terminal block pins 5 – N)
This functionality is valid when user mode is HEATING MODE.
Between pins 5 and N of terminal strip (see paragraph 4.1) an output is available (1 ph ~ 230V, 2A max) to activate a
backup external heat source (such as Electric Heater or Boiler).
This functions is activates using the NUI.
NUI Codes for this function:
106: 1 for External heat source (2 for Defrost Output)
148: OAT limit for External heat source (-20°C / +65°C)
150: Auxiliary OAT limit. This code is defining the EHS threshold value under witch both HP and EHS will be operative as
per algorithm. (-20°C / +30°C)
151: Auxiliary Delay. Delay time before switching the back-up EHS ON min. (1 min / 60 min)
152: Auxiliary Hysteresis. Delta T needed to activate the Auxiliary Heater. (1°C / 20°C)
153: SHW in OFF MODE. This code is defining if, when System mode is OFF, the SHW logic can be activated.
154: EHS OUTPUT. This code is defining the EHS output status when EHS is activated and OAT<Code 148
155: Main water pump vs EHS OAT. This code is defining the water pump logic when EHS is activated and OAT<Code 148
156: Additional WP vs SHW (0 Trace heater Output active)
157: Additional WP ( X and H terminal block pins 12 – N)
Water Temperature Set-point
E 152 Auxiliary Hyst
Indoor Temperature Set Point
HP System mode
Frost protection
EHS timer
AUX Delay
0=Always ON
1=ON/OFF based
EHS OUTPUT
on room T
CODE 154
2=ON/OFF based
on WSP
Max Frequency
0=Always OFF
MAIN WATER
1=ON/OFF based
CODE
PUMP
on EHS ON/OFF
155
2=Always ON
0=Always OFF
ADDITIONAL
1=ON/OFF based
WATER PUMP
on EHS ON/OFF
CODE 157
2=Always ON
If code 148 < OAT < code 150:
When LWT is below the water set-point minus the auxiliary hysteresis (code 152) starts the EHS timer (A). When the set delay
(code 151) is passed (B) the External Heat Source turns ON and the HP is regulated at the max frequency. The EHS turns
OFF when the LWT reached the water temperature set point (C) (EHS timer is set to 0). The additional water pump will be
activated depending by main water pump (always ON if main water pump is ON) and by the code 156 (ON or OFF as per SHW
activation).
If OAT < code 148:
The HP turns OFF (frost protection is active)
The EHS turns ON/OFF depending by setting of the code 154 (Always ON, Based on Room temperature or Water
Temperature).
The main water pump activation depending by the code 155 (always ON, always OFF or depending by EHS status)
The auxiliary water pump activation depending by the code 157 (always ON, always OFF or depending by EHS status)
NOTE:
the above strategies based on OAT value.
In case of EHS installation it is mandatory to install a thermal switch on the water circuit to protect the system from too high
water temperatures. This protection item has to be located Immediately downsteam the EHS (according to local/national
legislations).
SM_30AW.indd 62
OAT < T set in CODE 148
OFF
ON
OFF
ON
OFF ON OFF ON
ON OFF ON OFF
OFF
OFF
Depending by EHS ON/OFF
ON
OFF
Depending by EHS ON/OFF
ON
Control management
T set in CODE 148 < OAT < T set in CODE 148
A B C
ON
OFF
OFF OFF
ON
CODE 151
OFF ON OFF
ON OFF
OFF
As per standard logic
Depending on main water pump or, when SHW is active, by CODE 156
62
5
SHW: Sanitary Hot
Water
EHS: External Heat
Source
HP: Heat Pump
OAT: Outdoor Air
Temperature
WP: Water Pump
NUI Codes
106, 148,
150, 151,
152, 153,
154, 155,
156, 157
ON
OFF
OFF
OFF
OFF
30AW
14-03-2011 14:45:09