Fujitsu WATERSTAGE 112 Maintenance Document page 87

Heat Pump, Split System, Single Service, 3 phase
Mixing Valve Control
Line no. Programming line
938 Mixing valve cooling offset
941 Actuator running time
945 Mixing valve in heating mode
Mixing valve cooling offset
The cooling demand issued by cooling circuit 1 to
production is reduced by the adjusted value.
Example:
Zone 1: Heating/cooling
floor
Zone 2: Fan coils
Zone 1: Heating/cooling
floor
Zone 2: HCF
WARNING:
If these settings are not chosen properly the heat
pump may stop automatically due to the flow
temperature being too low. A safety mechanism is
triggered at 6°C to protect the exchanger from
freezing.
Actuator running time
For the 3-position servomotor used, it is possible to
adjust the travel time. With a 2-position servomotor,
the adjusted travel time is inoperative.
Mixing valve in heating mode
Determines the position of mixing valve 1 (Y1 / Y2)
during heating operation is activated.
Maintenance Document 1394-1
Configuration
938 = 10°C,
with 924 = 18°C
963 = yes
938 = 0°C,
with 924 = 18°C
963 = yes
If there is a second zone, this reduction should
enable the second zone to be cooled. To achieve this
result, the sub-cooling must be determined in
accordance with the type of emitter and the
parameter 963 "With prim control/prim pump" must
be set to "yes" to switch on the pump for the second
zone.
How the configuration affects control
with a 35°C outdoor temperature the flow
setpoint will be 18°C – 10°C i.e. 8°C
while in the first zone (HCF) it will be 18°C
through action of the mixing valve
with a 35°C outdoor temperature the flow
setpoint will be 18°C in both zones
This parameter is inoperative in installations where
heating and cooling
separate.
Control: the valve controls in heating and cooling
mode.
Open: the valve controls in cooling mode, and is open
in heating mode.
circuits are hydraulically
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