Hi @jakeymd1,
They are available (e.g. https://www.delcovalves.com/en/product/4-way-flange-electric-ball-valves-delco-valve/) but are very expensive and unlikely to be cost effective against tolerating a slightly inefficient radiator flow path. Two actuated 3-way valves would probably be no cheaper.
I don’t think it does - a quick check of the full NASA Message listing (NASA Protocol - Samsung EHS Wiki) doesn’t reveal a relevant output (and Samsung do not appear to adopt the large majority of these message numbers in the MIM-E03EN in any case).
My Samsung HTQ installer set up the controller for Heat only but I was thinking of implementing Cool mode ready for this summer. I asked Samsung Tech Helpline for guidance and they said: “When 3rd party controls are utilised cooling mode is activated by a separate cooling thermostat input. You would need a 240V signal into the B21 input terminal to switch the system to cooling mode.” and emailed me these diagrams:
But I confess I’m still confused about what exactly is required. What hardware for Cool mode have you installed (2nd roomstat, pump relay etc.)?