The domestic hot water failure will be suppressed for a time defined by the parameter SYS-02, after:
An alarm will be generated at the output "DHW_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 DHWS 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 DHWS continues until the system supply temperature has reached the target setpoint "CalcDHWTempSp".
Programming Hint
The alarm "DHW_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 16. Parameter List
Description |
Value Range |
Default Value |
Unit |
SST-06: P-band SST control |
1...1000 |
20 |
K |
SYS-02: DHW_Failure enable after release |
0...3600 |
1800 |
sec |
SYS-03: automatic/ manual reset; 0 = auto |
0 /1 |
1 |
- |