DIY troubleshooting of cooling and climate systems in housing and institutions

Faults in refrigeration and freezing systems, air conditioning and heat pumps, also called HVAC systems, can result in both resource and financial costs. We have collected practical advice for beginners in residential construction and public institutions for do-it-yourself troubleshooting of cooling and climate systems. We review the typical faults and possible solutions.

1. Is the cooling system powered on?

• If there are control lamps or displays lit, the system has power. Otherwise, check the main switch.
• Check if the RCD (residual current device) is tripped or if the fuses have blown.
• Larger cooling systems have two pressure switches (low & high pressure) that can shut off the compressor. If one of these trips, it indicates a fault in the cooling circuit. You cannot fix this yourself, and it is important to call a certified refrigeration technician.

2. Is there a lack of refrigerant?

• Start the system – if the compressor and fans run, but there is still no cooling.
• Check if there is refrigerant in the system – if there are many bubbles in the sight glass, refrigerant is likely missing. Call a refrigeration technician.

3. Is there wear and clogging?

• Check if filters (in ducts) or heat exchangers (air) are clogged. Clean the heat exchanger or replace blocked filters.
• The evaporator may release dripping condensate, where the drain can be clogged by dirt and/or bacterial growth. Clean the drain and drip tray.

4. Is there increased energy consumption?

Low refrigerant charge leads to both low cooling output and high energy consumption. For example, a 4°C increase in condensing temperature can result in more than 6% higher energy consumption.

• Evaporator setpoint: If the setpoint is too low, the evaporator temperature drops. Set the thermostat to the temperature actually needed.
• Increased energy consumption due to elevated condensing temperature: The condensing temperature is normally not adjustable, but it can rise if free airflow to the condenser is not ensured, or if the condenser is clogged. Clean and ensure proper air circulation. A 4°C increase in condensing temperature can lead to more than 6% higher energy consumption.

If these tips have not solved your problem, you should call for professional assistance.