The refrigerant inside heat pump lines is the medium through which energy is transferred into or out of a building. A certain amount of refrigerant leakage is inevitable over the heat pump’s time of operation, despite airtight closed loop system designs. Loss of refrigerant charge significantly decreases the operational efficiency of the heat pump system, increasing operational costs considerably. Additionally, most commonly used refrigerants are potent greenhouse gases, which further contribute to global warming. As a result, a small amount of refrigerant leakage can undo a lot of the environmental benefits of using heat pumps. Therefore, diagnosing and repairing sources of leakage is of utmost importance to ensure heat pumps meet performance standards. The following section details common sources of refrigerant leakage and methods of leak detection.

Leak Source

  • Capillary tubes connecting the condenser/evaporator to the distribution lines are common sources of leakage. Vibrations caused by the fans during system operation can dislodge the tubes and cause refrigerant leaks.
  • Accumulators are system components that store refrigerant to prevent flooding the compressor. This component is often made of steel, which is prone to corrosion and can cause a loss of charge.

Leak Detection

  • A small amount of ultraviolet dye is injected into the system and allowed to circulate. A UV light can then be used to spot the leaks in the system.
  • The heat pump system can be pressurized with nitrogen, which will leak through and generate a sound that can be used to find the leak.
  • Electronic leak detectors are handheld devices that use sound waves to locate leaks in pipe systems.

It is also equally important for customers to be educated on the effects of refrigerant leakage on their heat pump systems and be aware of how to diagnose them. Since refrigerant leaks tend to occur a few years into the system’s operation, they are often not covered by warranty. In those situations, it is common for customers to opt for a refrigerant refill rather than paying more to find and repair the leak, as detailed in the anecdote below.

“The customer had a new roof installed and the roofer shot a nail through the suction line which ran through a chase to the attic. The customer had the system filled three times before deciding on fixing the refrigerant leak. It took over 8 hours to find and fix the refrigerant leak. Add up the cost to find and fix the leak and compare it to the original three times the customer had the system charged. It would have been cheaper to find and fix the leak the first time than to wait as this customer did.”

Customer education on the downsides of refrigerant leakage is important to ensure the safe operation of their systems and will also reduce callbacks to recharge the system when customers get the problem fixed right the first time.