Installation manual
36
HXHD125A7V1B
VRVIII system indoor unit
4PW62584-1A – 11.2010
9.7.
Multiple set point control
If you want to use multiple set point control, a temperature reducing
device (TRD) is needed. The temperature reducing device converts
the high inlet water temperature to a reduced water outlet
temperature which will be delivered to the appliance(s).
When temperature reducing devices are installed, the system can be
configured to use multiple water set points.
The water set points can be selected in function of multiple set point
operation patterns.
Below the 2 possible patterns are explained in detail.
Multiple set point control according to pattern A
During normal operation, domestic water heating and space heating
modes are separated and activated intermittent to fulfil a
simultaneous request. Therefor multiple set point pattern A can be
configured to allow simultaneous domestic water heating and space
heating operation without intermission.
Schematic overview:
■
During space heating operation, water is provided based on the
selected water temperature set point for space heating. A
shut-off valve (field supply) must be installed in the domestic hot
water tank coil circuit. The valve must be closed to protect the
domestic hot water tank from cooling down by lower temperature
water going through the coil during space heating. Connection
and control of this shut-off valve is the reponsability of the
installer.
■
During domestic water heating operation, the water temperature
set point is normally higher than the set point requested during
space heating operation. The valve allowing water to enter the
domestic hot water tank coil is open. The heat pump will deliver
water with a higher temperature which is needed for production
of the domestic hot water. At that time, the lower temperature
appliances have to be protected against the higher water
temperature by a temperature reducing valve.
The configuration of pattern A allows 2 space heating set points and
one (same as in the classic design) domestic hot water set point.
The request signals for space heating can be implemented in 2
different ways (installer choice):
■
thermo ON/OFF signal (from external room thermostat)
■
status signal (active/not active) from the corresponding
temperature reducing device (TRD)
The electrical connections on the unit should be done on the optional
demand PCB.
The configuration of pattern A is done by field settings:
1
Select the appropriate pattern: [7-02]=0
2
Turn on multiple set point 1: [7-03]=0
➞
[7-03]=1
Turn on multiple set point 2: [7-04]=0
➞
[7-04]=1
3
Enter the temperature multiple set point 1: [A-03] (see below)
Enter the temperature multiple set point 2: [A-04] (see below)
Configuration example:
Pattern A design
Classic design
Indoor unit
1
Domestic hot water shut-off valve (field supply)
DHW
Domestic hot water tank
TRD
Temperature reducing device
Space 1
Space 1
Balancing bottle
M
Space 1
DHW
Space 1
DHW
TRD
1
Protection is required by means
of a temperature reducing
device (TRD) (depending on set
point)
Indoor unit
DHW
Domestic hot water tank
TRD
Temperature reducing device
Space 1
Space 1
Space 2
Space 2
Balancing bottle
Set
point
Field
setting
Thermo status
Domestic
hot water
70°C
(a)
(a) The water temperature needed to reach this set point of course is higher
than 70°C.
[b-03]
OFF
ON
OFF
OFF
OFF
Space 1
65°C
[A-03]
OFF
ON/OFF
ON
ON
OFF
Space 2
35°C
[A-04]
OFF
ON/OFF
ON
OFF
ON
Resulting heat pump water
OFF
>70°C
65°C
65°C
35°C
Space 1
DHW
Space 2
TRD
TRD
TRD
TRD
Space 1
DHW
Space 2
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