For a 2-pipe system, a common pipe system is used for heating and cooling pre-control circuits.
These systems cannot provide heating and cooling energy at the same time. When the “HVAC_Mode” input takes the value “auto”, both, heating and cooling pre-control circuits will be switched off.
We need both pre-control macros, this macro and the cooling pre-control macro “PRCC_PreCtrlClg“.
For a correct 2-pipe system operation:
With these settings the heating pre-control will operate as shown in the next table:
Table 2. Pre-control heating operation
HVAC_Mode |
SYS-01 |
Pre-control Heating |
0,1 |
0 |
off |
2 |
0 |
heat |
3 |
0 |
off |
4 |
0 |
off |