As I recall that system is described as automatic heat. The system sort of works like Klima but only automatically controls heat.

The dial assembly is the control head I think. If it were Klima the duovalves would be controlled by the PBC push button controller. I would expect the ground signals to be coming from there. Check them first at the valve.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician