Heating Pre-Control in a 4-Pipe System

In a 4-pipe system we have two independent pre-control circuits, one for heating and one for cooling. In this case we can provide heating and cooling energy at the same time, when the HVAC_Mode input takes the value “auto”.

We need both pre-control macros, this macro and the cooling pre-control macro “PRCC_PreCtrlClg“.

For a correct 4-pipe system operation:


With these settings the heating pre-control will operate as shown in the next table:

Table 1.   Pre-control heating operation

HVAC_Mode

SYS-01

Pre-control Heating

0,1

1

off

2

1

heat

3

1

off

4

1

heat