Issue
101-VF/24 (Fan coil controller) allowing positive terminal load with cool air supply and one valve for heat.
Product Line
TAC Vista
Environment
- 101-VF/24
- 101-2VF
- 101-2VFC
Cause
If you have a single valve application such as radiant heat control, but you have a central system that brings in fresh/cooled air to the same space, you may want to use the terminal load in the central system to indicate a call for cooling.
Resolution
If you only configure the controller for one valve and set the water temperature and water temperature setpoint to only allow heating operation, then the terminal load will only be calculated from 0 to -100% (heating only). Nvo_unitStatus will stay in heat mode as well even if the room gets too hot.
If you configure it up for two valves then your terminal load will be calculated from 100 to -100%, indicating both heating and cooling load.