If the filtered outside air temperature is lower than the frost protection limit FRZ-03 (2 °C) and the frost protection is enabled (FRZ-01=1), the pre-control flow temperature cannot get lower than this minimum value defined in the parameter FRZ-02.
If the flow temperature is between the frost protection setpoint and the P-band of the flow temperature controller, the valve will be modulated between 0 and 100% and a heat demand will be sent to the heat generators.
If FRZ01 =2 additionally, then the heating pump will run in a cyclic mode switching on and off.
Table 6. Pre-Control Parameter List
Description |
Value Range |
Default Value |
Unit |
FRZ-01: enable freeze protection 0 = no frost protection 1 = limited to FRZ-02 2 = enabled with cyclic on/off |
0 ... 2 |
1 |
- |
FRZ-02: flow temp. setpoint frost protection |
2 ... 20 |
10 |
°C |
FRZ-03: OAT limit frost protection |
-50 ... 50 |
2 |
°C |
FRZ-04: frost protection heating pump runtime for cyclic on |
0 ...720 |
60 |
sec |
FRZ-05: frost protection heating pump delay for cyclic off |
0 ...180 |
5 |
min |