Performed preventative maintenance for a Lennox system model #XC14-042-230A07, serial #5816E01487. Upon arrival the homeowner stated that there was a loud banging sound coming from the system when it shuts down. The evaporator coil’s are clean and in good condition. Tested the drain pan, drain line and condensate pump with several bottles of water to ensure that there are no leaks or clogs. I observed the condensate pump running but when it stops it make a banging sound. The condensate pump is about 8 years old and should be replaced. The homeowner agreed and I removed the old condensate pump and installed a new 115v pro select condensate pump. I connected all the proper wiring and vinyl tubing. I tested the condensate pump with several bottles of water. The new pump is operating properly. Checked all electrical components needed for air conditioning to ensure that they are secure and in good condition. The air filter size 20x25x5 was replaced by the homeowner in July of this year. The