Water at faucets and shower heads only at 109°f. Inspected check valves on heating loop and cold water main as well as mixing valve, could not find any issue. I suspect the cold water is mixing somewhere in the domestic lines and feeding back to the mixing valve. Loud ductwork caused by restrictive return air cover Temp drop across AC coil is only at 16.5°f, recommended drop should be 18°f to 22°f. System can be rebalanced with r410a refrigerant.