Operation mode

The operation mode provides useful information for easy testing and debugging of the heat exchanger. This information is available as a parameter DISP-03 or the macro output "OperationMode".

The output operation mode must be connected to a multi-stage datapoint with the states as shown in the next table. Since BACnet multi-stage points do not support the value "0", the operation mode value range starts from "1".

Table 12.   Operation modes

DISP-02 OperationMode

Operation mode

Comment

1

heat exchanger has no demand

there is no external heat demand

2

secondary supply temperature control active

normal operation

3

primary supply temp limitation active

primary supply temperature limitation control has the minimum signal

4

primary return temp limitation active

primary return temperature limitation control has the minimum signal

5

periodic valve opening during limitation control

Open the valve to avoid measuring standing water during limitation control, if the valve control signal = 0%.

6

minimum pressure switch alarm

alarm at the input “SecMinPressSw”

7

outside air temp frost protection

If the secondary supply temperature becomes less than the value of parameter SST-02 (switching differential 2 K) and the outside air temperature is less than the frost protection limit OAT-01 (switching differential 1 K), then the SST control will be released. In this case, the setpoint will be the value of the parameter SST-02.

8

pump alarm

secondary pump alarm at the input ”SecPmpStatAlm”

9

system supply temperature setpoint failed

“SecSupTemp” < “CalcSSTempSp” –SST-06 for more than 600 sec after control start.

10

legionella protection function active

input “LegionellaActive” is active and increases the return temperature setpoint

11



12

maximum temperature limitation by max. thermostat

alarm at the input “MaxThermostat”

13

maximum temperature limitation by safety thermostat

alarm at the input “SafetyTherm”

14

maximum refill time exceeded

refill failed after a minimum pressure alarm (6)