It is necessary to cut a 10” round hole into the ductwork above the furnace, usually located at the rear or side. Then, a horsehair filter gets placed on top of the heat exchanger. This filter acts as a ‘trap’ to catch all the falling debris. The coils must be protected as it is far too difficult and time-consuming to remove pieces of debris if we didn’t use the filter. A 12”x12” access plate or also called a patch plate is then installed over the round hole to seal the ductwork and allow for further cleaning in the future.
What if I already have a hole cut into the furnace?
if you already have had a previous one cut by another furnace cleaner, it usually too small, because we use a 10” vacuum hose. Therefore, we need to cut a larger hole and use a larger plate. In some cases, we may use an existing 8” hole and re-cut larger if it’s in the proper location. The patch is made of sheet metal and gets mounted with 8 screws for a tight, sealed fit, and will not affect the performance of your furnace. The plate can be removed and the hole re-used for future cleanings, so it is just a one-time fee.