My synergy3, 5 ton heatpump has issues, It's been down for almost 2 years. At the moment it is kicking out on low pressure. ( with the guages on ) some times it will run on forced air just fine then switch it to in hydronic and it kicks out, return it to FA and it still kicks out. Just replaced the internal pump as the impelor fell of which fixed the high head pressure fault. don't know what to do. faults rotate from low water flow, to low pressure, had low airflow and high pressure. But did run fine in a/c. at one point. totally confused.