Arkansas HVACR NewsMagazine January 2025

HVACR NewsMagazine January 2025

Tech News

determine if the evaporator coil is clogged with dust when you can't visually see it! Remember, we need roughly 350-450 CFM per 12,000 BTU/HR of system capacity. Also, every 12,000 BTU is equivalent to 1 ton of cooling capacity. Because of this, a 3 ton system would need around 1200 CFM if we were figuring 400 CFM per ton. Make sure to read our "Refrigerant Charging and Service Procedures for Air Conditioning" book to learn more about airflow measurement methods and measuring the refrigerant charge. In reference to the video scope, you get what you pay for. You want one that has a light at the head and it is best if the head is moveable (articulating) to look around after the borescope is inserted into the system. Some video scopes also record the video display so you can share it with your customer. The photo below shows us using a Teslong video scope. Method 1: Use a Video Scope

5 Methods to Determine if The Indoor Air Conditioning Coil is Clogged with Dust!

When servicing an air conditioner or heat pump, we often notice a low airflow problem which needs to be fixed. If there is no indoor air filter or there is air skirting around the air filter because its not snugly fit, the dust will collect on the side of the indoor evaporator coil. Eventually, enough dust collects onto the coil to significantly reduce the amount of airflow crossing through the coil fins. This reduces energy transfer, increasing electricity bills and reducing the air conditioners effectiveness. You will often see low superheat and a frozen vapor refrigerant line and coil. Remember, a normal to low superheat and a low vapor line saturated temperature indicated low airflow but hopefully techs are measuring airflow before measuring refrigerant pressure! During air conditioning mode the evaporator coil is wet, creating an environment where dust just sticks right onto the wet coil until it becomes a mat covering the coil. On most air handlers (also known as fan coils), it is easy to visually inspect the bottom side of the coil for blockages. On a furnace and AC system, it is significantly different. Below are 5 methods to

One method to insert the borescope into the upstream or underside of the coil is to remove the furnace limit switch while the power is off. This provides a pathway into the furnace heat exchanger area. After inserting the borescope in an upwards manner, the display shows the underside of the coil. Use the articulating dial to move the camera position.