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Building Technologies Division
User Manual RWF55...
CC1U7867en
Infrastructure & Cities Sector
5 Operating modes
05.11.2013
5.8 Thermal shock protection (TSS)
Note!
Functions
Cold start of plant
and
Thermal shock protection (TSS)
are interlocked.
Only one function can be activated, but never both at the same time.
The controller comes with thermal shock protection (TSS) deactivated; it can be
activated at the configuration level.
Reference!
See chapter 8.5
Thermal shock protection (TSS)
rAFC.
The function is automatically activated when the actual value drops below the
adjustable limit value
rAL
(exceeds the adjustable limit value with the cooling controller).
In that case, the setpoint is approached via a ramp function.
Gradient and slope of the ramp
rASL
are adjustable. The setpoint ramp has a
symmetrical tolerance band
toLP
. If, during the startup phase, the actual value leaves
the tolerance band, the setpoint ramp is stopped until the actual value returns to a level
within the tolerance band. The startup phase is ended when the setpoint of the ramp
function reaches the final setpoint
SP1
.
Note!
When thermal shock protection (TSS) is active, the controller operates in low-fire
operation. The response threshold (q) is active.
t
t1
t2
SP1
toLP
rAL
t3
t4
Temperature
78
66
d2
0e
/0
21
2
Figure 19: Thermal shock protection (TSS)
Key
Setpoint (w)
Actual value (x)
Interlocking
Function