Complete 1 system preventative maintenance and system. The customer noticed that system freezing up at the suction line. Check and find system operating within manufacturer spec. Find basement bedroom zone damper not operating due to faulty damper system. Give customer option to replace Honeywell zone damper. Find supply air temperature 45 degrees when upstairs zone off and only basement office operating. Adjust air supply temperature to 45 degrees to help prevent freezing. System operating at this time. The customer has 5 Ton heatpump system with 3 zones.