Hey folks,
It comes up, from time to time, the question about using direct fired equipment with DX cooling, and taking in account the flammability of the new refrigerants.
Here’s the answer from AbsolutAire.
“The purpose of this Letter is to outline AbsolutAire compliance with UL 60335-2-40 when equipped with an A2L cooling coil. All AbsolutAire products, including direct-fired, indirect-fired, and no-heat units, may be operated with cooling coils containing an A2L refrigerant charge. UL 60335-2-40 provides guidance for safe construction and operation of these units. AbsolutAire products are manufactured with coils designated for either R32 or R454b refrigerants to comply with these guidelines.
The key elements of compliance that apply to AbsolutAire units are sensors that can detect the presence of refrigerant (i.e. leak) above a given threshold and unit behavior when such a leak occurs. Once the levels of leaked refrigerant return below the threshold, and not less than 5 minutes, the unit can return to normal operation. One sensor is supplied with each installed coil and integrated with the unit controls. Depending on equipment options the unit operation will be as follows while the sensor level remains above the threshold:
- The supply air fan will remain energized.
- Burners and igniters will be disabled.
- Cooling compressors will be disabled (or cooling enable contact disabled).
Currently, we are in the process of obtaining 3rd-party validation of our compliance to UL 60335-2-40 by Intertek.”
With that, you can feel safe to use AbsoluteAire for your heating applications and DX cooling using direct and indirect fired gas.
Now you know
Tom
