DLS A2L Dissipation Error Codes

With the industry shift to mildly flammable refrigerants, most new HVAC systems now require some manner of dissipation in the event of a major refrigerant leak. DLS and Crossover systems are no exception and because of this we have new error codes. 

Here is a short list of the error codes associated with dissipation on the Carrier and Bryant DLS and Crossover products that you need to know about and what each code means. For good measure, at the end of this article, I have added some specifications and information on the dissipation sensor that is currently used in most (not all) DLS and all Crossover A2L refrigerant products. 

FH CC – Sensor malfunction. 

• This error indicates an open or non-powered dissipation sensor. To troubleshoot, check for proper voltage to the sensor and that it ohms out correctly (see below). 

EH C1 – Refrigerant leak detected …Audible alarm triggers! 

• Tell your customers: “Don’t call 911! Call you!” This error means the dissipation sensor has picked up refrigerant higher than 10% of the LFL (lower flammability limit). The alarm can be silenced by one press of the power button on a handheld remote, the power button on a wall control, or the forced operation button on most indoor units. Silencing the alarm doesn’t take this system out of dissipation but will stop the persistent beep coming from the indoor unit. 

• Be aware, it is possible for sensors to trip on things besides R454. Many things which use refrigerant based propellants can set it off. Expanding foam is at the top of the list. In the lab, we force dissipation responses using canned air. 

EH C2 – Sensor out of range (high) …Audible alarm triggers! 

• Signal voltage from the dissipation sensor has risen above the upper limit. There have been no reports to our group of this error code happening in the field. 

EH C3 – Sensor out of range (low) …No Audible alarm. 

• Signal voltage from the dissipation sensor has fallen below the lower limit. There have been no reports to our group of this error code happening in the field. 

EC C1 – Refrigerant leak detected from another unit (multi-zone). 

• When one unit in a multi-zone system goes into dissipation, this code will show on all other indoor units. 
• Only the unit in dissipation will have an audible alarm and display EH C1.

Disclaimer: The technical statements, information and recommendations contained herein are believed to be accurate as of the date hereof, but Mingledorff’s does not make representations or warranties, express or implied, as to its accuracy, its completeness, or the results to be obtained. The information is being provided for informational purposes only and is intended for use by persons having adequate skill and expertise regarding the proper selection, use and application of the products and recommendations and at their own risk and discretion.