Fujitsu Waterstage Comfort Series Maintenance Document page 73

Split system single phase type
Mixing Valve Control
Line N° Programming line
938 Mixing valve cooling offset
941 Actuator running time
945 Mixing valve in heating mode
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
With prim controller/system pump
Line N° Programming line
963 With prim contr/system pump
(no / yes)
This setting specifies whether the cooling circuit is
supplied from the primary controller or from the primary
pump (depending on the installation) It can also be used
to provide cooling to the second zone.
Maintenance document "1792 - EN"
Mixing valve cooling offset
The cooling demand issued by cooling circuit 1 to
production is reduced by the adjusted value
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.
Configuration
938 = 10°C,
with 924 = 18°C
963 = yes
938 = 0°C,
with 924 = 18°C
963 = yes
Mixing valve in heating mode
Determines the position of mixing valve 1 (Y1 / Y2) during
heating operation is activated
This parameter is inoperative in installations where
heating and cooling circuits are hydraulically separate
Control: the valve controls in heating and cooling mode
Open: the valve controls in cooling mode, and is open
in heating mode
Warning:
In the case of a radiator or any other emitter which does
not support the cooling mode in zone 2, this setting must
remain on "No"
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
- 73 -