My geothermal is 8 yrs old has cooled great until last week. I have 3 ton Bryant, 1800 sq ft ranch all brick and full unfinished basement. New loop last year. The temperature out of my registers is about 68 to 70. Not good. I had it checked 2 times by dealers. They checked for leakers, coolant, pressure and temp in loop. They said everything was ok. My thermostat never goes up. It did a week ago. My basement where my geothermal is, is warmer this year by 2 degrees never before. Not short of rain. Loop is horizontal. Why does it not cool better. The air is cool but not cold like it was before. I am about to pull my hair out, the temp have been in the 90's but it has been that hot in previous years. I think maybe the compressor is shutting off and on as the register temp sometimes is the basement temp. The temp varied a little before but not 2 degrees please help. I really don't know what to do. The techs say it is ok. But I know how my unit has worked for 8 years and I had one before that for 19 years. Thanks in advance

It sounds like you need new HVAC technicians if you have 70F air exiting your registers and they said everything is OK. You should be getting approximately 20F drop across the cooling coil, i.e. if your return air at the return grill is 75F, then air leaving the unit should be ~55F.

Does your geothermal unit control board have any status lights on to indicate a fault condition?

Why did you have to replace the loop after only 7 years?

Does your loop pipes where they enter the unit have pressure/temperature (PT) ports to allow taking these measurements? Can you measure the entering and exiting loop water temperature? Also, the entering and exiting loop water pressure? Those items along with the exact model number of your geothermal unit can be used to diagnose if it is rejecting its rated amount of heat to the loop.

I put in a another loop after the first one started leaking after 26 years. New geounit 7 years ago. The guy who put in the first loop said it would last 50 years he is not around. The unit is keeping the temperature in the house 74 and only varies 1 degree. It is a 2 stage 3 ton. The coolest temp I can remember was 64 or 66

The 2 techs who Checked it out said the temp and pressure in the loop was ok and no leaks. I think I hear the compressed kicking off and on T times. But the fan is still running