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Why is my HVAC system not running properly?

Occupants within buildings such as offices, schools, hotels and hospitals rely on efficient HVAC systems to provide safe, healthy air, while for building owners and managers reliability and energy efficiency are also a major concern.

Therefore, when HVAC equipment begins operating below its normal level, it’s useful to know some of the possible causes. If your air handling equipment isn’t working as it should be, here are a few things to look out for.

Blocked filters

The frequency of filter replacement depends heavily on system usage. HVAC equipment running continuously will require filters to be replaced monthly in many cases, while infrequent use may only demand annual changing.

Defective motor

Fan motors in the air handling unit (AHU) and the outside condenser unit need to be serviced regularly to ensure efficient operation. Components such as bearings and the shaft are prone to wear and should be monitored and replaced when necessary.

Clogged condenser coils

Dirt, dust and other debris may settle on the coil surface, which, if left to accumulate, can significantly reduce efficiency. This is because of the reduction in airflow which forces the system to work harder in order to achieve the desired performance.

Insufficient or excessive refrigerant

A lack of refrigerant in the system can lead to the compressor overheating. Too much refrigerant, however, can back up in the compressor and cause high pressure and increased discharge temperature.

Damaged and dirty fan blades

Bent or snapped fan blades mean reduced efficiency and should be replaced immediately. Fan blades are an essential item to be checked as part of a routine HVAC servicing regime.

HVAC maintenance can be a time-consuming process, and smaller businesses simply may not have the personnel to carry it out. However, neglecting your AHUs can lead to performance problems while jeopardising indoor air quality.

Gibbons HVAC services offer bespoke maintenance packages to look after every element of your air-handling system. Our expert engineers will help to improve every aspect of your system:

  • Increased operational life of equipment
  • Greater energy-efficiency
  • Lower running costs
  • Best-possible indoor air quality for building occupants

To discuss your requirements, call Gibbons HVAC Services Manager Andrew Knight on 07850 204915 or email

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