Hey everyone. Been in our current home for a little over 3 years now. The heating and air is ran off of a geothermal unit under the house. I know VERY little about this system but it is driving me insane! Last summer and now this summer, it starts the summer off cooling very good then 2-3 weeks in it just starts blowing room temperature air. I've checked all the usual things, filters, water pump, etc. but for some reason can't find the issue. I've 2 different companies come out and look at it. They've refilled the coolant and, according to them, thoroughly went through the system and can't find anything wrong. I found online someone saying the water solenoid valve could have gone out and that you could manually open it to get it cooling again. I can't find a valve like the one I keep seeing online (TACO Valve). I'm attaching a picture of the valve coming off of the water out. Anyone know what this valve is? And PLEASE any suggestions would be greatly appreciated!