Any HVAC experts?

[weyburnt]

Yes that is a relay. All hrvs have this relay. All I was saying was op did not need to add an additional relay as the hrv would take care of it. This is the relay that turns the furnace fan motor on. And I have checked my setup. It is wired diagram one and my furnace fan runs independent of my cooling. And yes we need a y and a g terminal so the t stat operator can run the fan and the Ac independent of one another. However if y and g are common, as you say than anytime one runs the other would run as well. Even switching the summer fan to on would cause the Ac to run at all times