Fujitsu WOxK112LCT Design & Technical Manual page 88

Supplementary source
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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 FUNCTION
3700 Release below outside temp
3701 Release above outside temp
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 FUNCTION
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 FUNCTION
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.
 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.
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
- (CS01 - 43) - - (CS01 - 43) -
Control system