Domestic Hot Water (Dhw); Second Domestic Hot Water Tank; Domestic Hot Water Distribution Control; Domestic Hot Water Pre-Heating - Carrier HSM User Manual

6.8 - Domestic hot water (DHW)

6.8.1 - DHW setpoint
The domestic hot water setpoint is determined in the
SETPOINTS menu - the default is 55°C. This setpoint is
transmitted to the heat pump, when the HSM changes in
the domestic hot water production mode.
6.8.2 - Priority
Priority is given to the domestic hot water production.
However, to avoid a temperature drift in the heating loops
it is designed to regularly change from the DHW mode to
the heating mode (see the following chapter).
6.8.3 - Domestic hot water production time/stop time
If the HSM changes to the domestic hot water production
mode, it must remain there for a time "dhw_dur" defined
in the DHW_CONF menu. At the end of this time, the
HSM is allowed to return to the heating mode, if required.
In the same way, if the HSM changes to the heating mode,
it remains there for a time "dhw_stop". This time prevents
a temperature drift in the heating loops.
6.8.4 - Anti-legionella mode
The anti-legionella function permits heating of tank and
piping to eliminate the risk of legionnaires' disease.
The day, time and duration of the anti-legionella mode
operation are configurable in the GEN_CONF menu.
The anti-legionella mode setpoint is determined in the
SETPOINTS menu - the default value is 65°C. This setpoint
is transmitted to the heat pump when the HSM changes to
the domestic hot water production mode.
If a pre-heating pump is installed, this is controlled in the
anti-legionella mode.

6.9 - Second domestic hot water tank

A second domestic hot water tank can be installed.
6.9.1 - Additional pump P7
Pump P7 is started if the temperature of additional tank
GT7 falls below the DHW setpoint minus hysteresis. It is
stopped when the temperature again rises above temperature
GT7 minus 2 K and is under the DHW setpoint.
6.9.2 - DHW back-up pump P7-2
Pump P7-2 is started when the 'Back-up heating allowed'
information is activated and when temperature GT7 minus
2 K is below the DHW setpoint threshold minus 5 K (see
chapter "Back-up heating"). This pump is stopped if the
information returns to zero or if GT7 minus 2 K again rises
above the DHW setpoint.
6.9.3 - Anti-sticking
If parameter 'dhwpmp_s' of the PUMPCONF menu is
configured to 'YES', additional pump P7 is started for five
seconds every Monday at 12.03 hours and back-up heater
pump P7 minus 2 K is started every Monday at 12.04 hours.

6.10 - Domestic hot water distribution control

If a three-way domestic hot water distribution valve is
installed, this mixing valve SV35 is controlled within 0-10 V
by a PID so that the hot water distribution temperature
GT5 is controlled around the DHW setpoint.

6.11 - Domestic hot water pre-heating

If a domestic hot water pre-heating pump is installed, this
pump P5 is started when the distribution temperature GT5
is below the DHW setpoint minus 10 K. It stops when this
temperature again rises to the DHW setpoint minus 5 K.
This function permits instant hot water at the tap, even if
the domestic hot water distribution system is very long.
6.11.1 - Anti-sticking
If the "dhwpmp_s" parameter of the PUMPCONF menu
is configured to "YES", pump P5 is started every Monday
at 12.05 hours.

6.12 - Back-up heating

6.12.1 - Heating time delay
The "bck_pull" parameter in the BCKUPCONF menu,
that is configured by the user, shows the time delay before
the start-up of the back-up heater.
This function permits the heat pump to reheat the water
circuits using thermodynamic heating before starting the
back-up heating (often increased energy consumption).
This time delay is not initialised when an alarm is cancelled.
6.12.2 - "Back-up heating authorised" information
Operation of the back-up heating is authorised, if the heat
pump is at maximum capacity and the heating time delay
has expired.
6.12.3 - Back-up heating with electric heating stages
As an option, the HSM can control up to four electric heating
stages, used as back-up heating.
If the second domestic hot water tank is installed, the
temperature of loop 1 is controlled by electric heating stages, if
the 'Back-up heating authorised' information is activated.
Each electric heating stage is now started successively,
based on the heating load.
If the second domestic hot water tank is installed, two PI
control loops are used:
• The first PI controller regulates mixing valve SV31 to
control the temperature of loop 1.
• The second controller regulates the temperature of
the DHW back-up loop.
If the 'Back-up heating authorised' information is activated,
the controller with the largest output is used to control the
electric heating stages successively.
In summer mode, only the electric heating stages are
controlled by the second PI controller, when mixing valve
SV31 remains closed.
en
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ENGLISH