Secondary Supply Temperature Failed Alarm

After controller start, the secondary supply temperature failed alarm will be suppressed for a time defined by the parameter SYS-02. An alarm will be generated at the output "HE_Failure" if the secondary supply temperature drops below the calculated P-band, defined by parameter SST-06, for more than 600 sec (fixed value). This alarm can be reset by the input "Reset".

In case of manual reset and a secondary supply temperature failed alarm, the temperature control of the heat exchanger will be stopped until the alarm is reset by the input "Reset".

In case of automatic reset and a secondary supply temperature failed alarm, the temperature control of the heat exchanger continues until the system supply temperature has reached the target setpoint "CalcSSTempSp".

NOTE:

To disable this alarm function, set parameter SYS-02 to "0".

Programming Hint

The alarm "HE_Failure" can be used to enable a spare boiler which must be released in case of emergency only. The alarm can be reset manually or automatically as defined by parameter SYS-03.

Table 14.   Parameter List

Description

Value Range

Default Value

Unit

SST-06: P-band SST control

1...1000

20

K

SYS-02: HE_Failure enable after release

0...3600

1800

sec

SYS-03: automatic/ manual reset; 0 = auto

0 /1

0

-