Found system outdoor unit locked out. Power cycled unit and ran in heat mode. Suction pressure drops dramatically and never gets over 55psi, even with the outdoor txv sensing bulb in hand. Followed train troubleshooting guide for their great pumps which led me to verifying the charge before condemning the txv. Preformed leak search and found leaks in evaporator coil. Customer also told me that the unit struggled to cool towards the end of summer. Put in a part quote request form to verify whether or not the unit has a Part warranty. Charged the system with 4 lbs of refrigerant until the system pressures looked normal. Unit is heating fine.