Thanks for having this forum as its proving to be invaluable ! We purchased a new to us home back in Aug. It has a closed loop Geothermal Heat Pump system that is approximately 10 years old. During the switch over from Cool to Heat we noticed that the unit would not switch from cool to heat unless the entire system was powered down and then Heat was called for. We found out that the EWC NCm-300 zone board was bad.. So I got myself a new board and was ready to install it, then I started to dig into the system and can't figure out why its wired(SET-UP) the way it is... hopefully everyone here can help me figure it out !! Its a Climatemaster Tranquility 27 5 Ton Air Handler ( TAH064AGSMCS), Climatemaster TTS064BGC00CNNS 5 Ton Split R410A Copper Coil no HWG Heat Pump Climatemaster AGL15C 15KW Electric Heater EWC NCM300 Zone Control Board with two zones set up 14'' Barometric Bypass Damper Zonex TREC 20 x 8 Single blade Damper Zonex, TREC 22x12 Rectangular Damper. Based on the wiring at the thermostat / zone board / and heat pump, it looks to be configured as a single stage Heat pump with AUX electric heat. Based on what I can find out this unit , it should be a two stage unit with a variable speed fan.. I can't figure out why it would be set up as a single stage unit ? Could it be thermostat or zone board limitation ? or just an easier install ? Im a total novice but can pick stuff up pretty quickly. Just trying to decide if I should upgrade the zone board and get the wiring correct to take advantage of the dual stage efficiencies ? Any thoughts or help is appreciated !!