Incorrect pressure testing caused heat pump explosion
9th March 2025
POLAND: Investigators looking into the fatal domestic heat pump explosion in Chrząstowice in August, have revealed that the cause was the failure to use a non-reactive gas during pressure testing.
The heat pump explosion killed two people, a 30-year-old engineer, who was servicing the unit, and the 45-year-old property owner. They were said to have suffered multiple injuries to the chest, head, arms and legs. A third individual was injured and taken to hospital.
The explosion was said to have torn the heat pump apart with metal fragments damaging the walls and roofs of neighbouring houses. A fragment of the casing was found in the parking lot of a store 300m away.
The air-to-water unit was using R410A.
Although the investigation is continuing, a spokesman for the Opole district prosecutor’s office is said to have told the Gazeta Wyborcza newspaper that the cause of the explosion was the use of the wrong substance by the person servicing the heat pump to check the tightness of the installation.
It is thought that the serviceman most likely used oxygen, which, when introduced into the cooling system in combination with oil vapours, caused the explosion.
Pressure testing a DX system with oxygen instead of a non-reactive gas like nitrogen is extremely dangerous. The oxygen can react violently with oils and grease present in the system, leading to potential explosions.
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