You must change the setting on Water Heater for Winter

The type of water heater we have feeds into the heating and cooling system.
In winter you must move the two levers on the side of the water heater to OPEN which allows hot water to run through the heating system.

In summer you must move the two levers to CLOSE so there is no hot water running through the cooling system making coolng your unit using the Air Conditioner nearly impossible.

I did not know this for several years and so could not get my unit to cool down using the Air Conditioner for hours and still not reducing the temperature barely at all.

No one tells you this when you move in and it is a very unusual system.
Try it, it works.