Basement zone continuing to heat...

JohnJay1

Customer has a heat pump/furnace for heat. They have a zoned system with three thermostats and three dampers utilizing a zone control board. 

The downstairs zone continues to heat even though thermostat is not calling. We disconnected the thermostat and still continues to heat. 

The control board shows that zone "on" and heating with no call for heat. Also tried disconnecting the damper wiring to that zone on the control board and no change. Still heating and led on.
Any suggestions on what to look for here?
I haven't worked on a zoned forced air system before wired to heat pump and furnace for emergency heat.

Thanks in advance!