Carrier AquaSnap Plus 30AWH004HB Installation Manual page 18

Auxiliary accessories connection
Additional Water pump (ADD WP )
It is possible to connect an additional water pump through the
pins 12 and N. It is managed in the following way:
If OAT > temperature set in NUI code 148.
The additional water pump activation depending by the NUI
code 156.
1. ON/ OFF depending on the outdoor unit water pump logic,
in case of SHW activation ADD WP is ON;
Signal for requesting an External Heat Source (EHS)
Between PINS 4 and N of the terminal strip (see Fig. 17),
there is an output (1ph ~ 230V, 2A max) that can be
programmed using the remote User Comfort Interface (see
the control manual, Installation Menu code 106).
Two different strategies are possible based on Outdoor Air
Temperature:
1) Turn off heat pump and activate backup heat source. This
function is activated when OAT < Temperature set in NUI
code 148 (default value -20°C). In this region heat pump
turns off and external backup is activated following one of
below logic (NUI CODE 154):
• Output always on (NUI CODE 154=0) assumes backup has
its own regulation.
• ON/OFF based on room temperature set point
(NUI CODE 154=1)
• ON/OFF based on water temperature set point
(CODE 154=2) in case NUI is not installed/available.
2) Both heat pump and backup heat source activated in case
Heat Pump delivered power is not enough. This function is
External water circulator for 30AWH__X unit
Units without an integrated pump allow driving an external
one.
External Alarm Input
On PIN 21 of the terminal strip (see Fig. 17) an alarm input (dry
contact) is available to force off the unit.
When the contact is closed (Between pin 21 and 3) the whole
system is turned OFF (Unit OFF, WP OFF, GMC alarm n° 2). When
the dry contact open the system turns ON and works in the
last configuration.
10 30AWH
2. ON/ OFF depending on the outdoor unit water pump logic,
in case of SHW activation ADD WP is OFF;
If OAT < temperature set in NUI code 148.
The additional water pump activation depending by the
NUI code 157 (0. always off, 1. on/off depending by EHS, 2.
always on).
activated when OAT < Temperature set in NUI code 150 (but
OAT > temperature set in NUI code 148). In this region HP
keeps working and backup heater turns on if set point on
water is not reached by 5°C (value can be set with NUI CODE
152) for 10 minutes (value can be set with NUI CODE 151).
Backup heater turns off when set point on water is reached
again.
IMPORTANT NOTICE :
In case of SHW activation (pins 13-15 closed) heat pump will
turn on and backup heater will turn off. This will happen in
both the above strategies.
WARNING :
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 downstream the EHS.
The signal (1ph ~ 230V, 2A max) is supplied between PINS
16 and N of the terminal strip (see fig. 17).
It is possible to use this feature connected with different
external control systems and/or safety devices. For example
in case of danger an external safety device could send an
output alarm signal to close the contact. So the outdoor unit
turns off and remains in that condition until the dry contact
is reopened.
(Fig. 17)