Velbus or function for hvac

For my HVAC system I would need a kind of OR logic that commands a pump whenever a room in the house is asking for heating. The pump may only stop if all of the rooms do not need any heating.

This is a key feature of a Velbus system and is detailed in the programming guide -

All you need to do is add a “Momentary” action to each and every “pump” channel of your Velbus thermostats to the relay that controls the pump.

In the configuration of the thermostats you will also find an “unjamming” options.

All this does is trigger the pump or heater channel for 1 minute every day.

This is especially useful if you have motorised valves or pumps that have a risk of being dormant for many months, where there is a risk of them seizing up due to lack of use.