A teaching post related to my last one: When dealing with commercial heat pump RTUs, you need to be aware of the terminal board for the thermostat connections. Some manufacturers, like trane, still use a terminal specifically for the reversing valve, and so the thermostat can be set up normally. Other manufacturers, like carrier and York, use conventional wiring for their heat pumps. The conventional wiring is used because the Y1 circuit goes through the economizer, and you don’t want that opening during a heat call! So with these systems, you’ll set up your thermostat as a 2 heat, 2 cool conventional system. #teachme #themoreyouknow

Posted by hvac_grammarian at 2021-02-20 23:55:35 UTC