Theoretical

Let's wire the Havaxer 01 to become a complete HVAC controller handling one heating/cooling circuit.

• Connect the outside temperature sensor to TEMP1.
• Connect the domestic hot water (DHW) temperature sensor to TEMP2.
• Connect the system supply or buffer top temperature sensor to TEMP3.
• Connect the circuit supply temperature sensor to TEMP4.
• Connect the circuit mixer to TRIAC1 and TRIAC2.
• Connect the circuit pump to RELAY1.
• Connect the heat source controller to RELAY2. When the RELAY2 is on, the heat source should start heating the supply water.
• Connect the DHW changeover valve to RELAY3. And the DHW charge pump if not provided by the heat source.

By creating a logic bridge between all these connections in an application, the program might do something like this:

1. Monitor the TEMP2. When drops below 42° C, turn the RELAY2 and RELAY3 on. When climbs above 48° C, turn the RELAY2 and RELAY3 off.
2. If circuit is enabled, turn on the RELAY1. If not, turn the RELAY1 off, TRIAC1 off and TRIAC2 on (closing the mixer).
3. If circuit is enabled, monitor the TEMP4. When drops below 26° C, turn the TRIAC1 on for 3 seconds. When climbs above 28° C, turn the TRIAC2 on for 3 seconds. Repeat after 15 seconds.
4. Monitor the TEMP3. If it drops below the minimum required supply temperature of the circuit, turn the RELAY2 on. Turn it off when the TEMP3 reaches that temperature plus 7 K or after 60 minutes.
5. Monitor the TEMP1 and adjust the circuit required supply temperature.

The temperatures and times here are for example only.

There is still TEMP5 available. You can use it to monitor a room temperature, for example.

Additionally, the SIG1 can turn an off-board relay on and off directly, for example a relay for a DHW circulation pump.

By connecting a standard electrical light switch to OC1, you can read a user demand for extra hot water, for example.