How To Prevent Your Customer’s HVAC Unit From Overheating


21 December 2015
HVAC Unit maintenance
During warmer periods, air conditioners are pushed to the max, in order to keep their users cool and fresh. Unfortunately, HVAC systems have their limitations too and can quickly overheat if measures aren’t taken to prevent them running out of steam.

​Installers of these units need to know how to handle overheating systems and take steps to ensure any damage is minimised. Below is a list of common reasons HVAC units overheat and how you can help stop them from occurring.

Clogged-up Air Filters

​In a number of circumstances, dirty air filters can cause major problems for air conditioning unit. Since filters are designed to trap and collect dirt and pollutants in the air, they can quickly become clogged. This causes restricted airflow through the unit and means it must work harder to cool the room it is installed in. Eventually, this can lead to stress in the pump and, at this point, overheating is inevitable.

To prevent the airflow from becoming restricted, installers should check the air filter is clean before use. They should also advise their customers to switch out the filter every month or so, to allow the unit to breathe. 
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Dirty Condenser Coils

​Often customers will complain that the outside part of their air conditioner is too hot. Because the condenser coils are dumping heat into the outdoors, anything that prevents them from doing this will cause the inside of the system to overheat. Since dirt is an insulator, condensers that haven’t been cleaned for a while are smothered by the filthy layer that forms on top them. The refrigerant that absorbs hot air from inside the system is now too warm to perform this task and the heat just keeps ramping up. 

Condenser coils should be sprayed with specialised cleaning spray in order to prevent dirt from settling on them. This should be done not only during installation, but also in performance checkups, if this is a service you provide. 

Leaking Refrigerant

Refrigerant is like an air conditioner's blood supply and without it, the unit can’t draw in heat from the surrounding air. Refrigerant isn’t used up like other fuels, so if a system is running low on it, then there must be a leak somewhere. Refrigerant leaks can occur during installation if the unit is fitted improperly.

​These leaks often happen in either accumulators or heat pump coils, when contractors fail to connect them in the correct manner. Wear and tear is also an issue and any rusting in these parts should be dealt with immediately.

Poorly Ventilated Compressors

The compressor continuously pumps refrigerant through the air conditioning system and can therefore be prone to overheating too. If the compressor’s bearings are failing then this can generate excess resistance, but the main cause of compressor exhaustion is poor ventilation.

​When compressors lack a quality air supply they are unable to dissipate enough heat to cool down. Stifling the compressor is a surefire way to cause it to overheat and shutdown. Contractors should bear this in mind when installing or servicing the compressor, ensuring there are no blockages within 18 inches of the unit and at least 3 feet of airspace above it. 
Tony Ellerker has worked in the building services and construction industry for over twenty years. He is currently the director of Blakes M&E Building Services.