Customer called due to no heat using water source heat pump connected to roof water loop system. Service technician determined vertical in-ceiling 2 ton water source heat pump and back up heater needed replacing. Installation complete. Customer very happy and educated that it is very important to have a strainer installed to prevent closed loop sludge cogs for condominiums using roof top water tower loops. Also, inner loop temperature sensor installed to prevent backup aux electric heater from coming on accept in extreme cold weather conditions. Will recommend to all her friends in Henderson's Warf.