Fujitsu Waterstage WS G140DC6 Series Maintenance Document page 73

Split system (Single phase and 3-phase type)
4.3.9 Supplementary source
A supplementary producer can be operated in
addition to the main producer (heat pump).
Release of the supplementary producer depends on
a number of parameters a detailed description of
which is given on the following pages.
Line no. Programming line
3700 Release below outside temperature
3701 Release under outside temperature
Operation of the supplementary source is released
only when the composite outside temperature lies
above or below the set temperature limit.
This enables the supplementary source to lock in a
selected outside temperature range to ensure
bivalent operation of supplementary source and heat
pump.
Overtemperature protection
Line no. Programming line
3705 Overrun time
Overrun time of release for the external source: If the
integral indicates another heat deficit before the
overrun time has elapsed, the release remains
activated.
Flow control
Line no. Programming line
3720 Switching integral
3723 Locking time
Switching integral
The temperature-time integral is a continuous
summation of the temperature differential over time.
In this case, the decisive criterion is the difference by
which the temperature lies above or below the
common flow temperature setpoint.
The temperature-time integral gives consideration not
only to the period of time, but also to the extent of
over-/undershoot. This means that when the crossing
is significant, the supplementary source is released
earlier, or locked earlier, than with minor crossings.
QX2
QX3
TVx Actual value of flow temperature
TVw Flow temperature setpoint
+ Int Surplus integral
- Int Deficit integral
t1 Overrun time (not completed)
t2 Overrun time (fully completed)
QX2 Release output QX2
QX3 Control QX3
Maintenance Document 1544-1
 Release is effected via release relay QX2
 2-position control is effected via control relay QX3
 Ux can be used to transmit the supplementary
source a DC 0...10 V signal for the required
temperature/output setpoint
To ensure continuous release of the supplementary
source, setting "---" must be selected on the
respective operating lines.
If both release values are enabled, the outside
temperature must satisfy both criteria, thus ensuring
release of the supplementary source .
If the set overrun time elapses before the common
flow temperature drops below the common flow
temperature setpoint, the release is deactivated also.
Locking time
The locking time enables the heat pump to reach a
stable operating state before the supplementary
source is allowed to switch on.
The supplementary source is released only when the
locking time has elapsed.
The locking time starts as soon as a valid flow
temperature setpoint is available.
Calculation of the release integral starts only when
the locking time has elapsed.
QX2
TVxSch Actual value of common flow temperature
TVwSch Setpoint of common flow temperature
A Request
QX2 Release output QX2
T Locking time
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