To (Hot Gas) Bypass or Not (Hot Gas) Bypass

To (Hot Gas) Bypass or Not (Hot Gas) Bypass


We have all asked ourselves the question above on a job and usually, we go with the safe bet of adding hot gas bypass to a system. Even in the design engineering and product management world, we still have added the option for years to our equipment to protect the unit from damage in certain applications. We have recently created a document that brings together years of experience to discuss the hot gas bypass option. This document will help you talk with your customers about the option and help them understand why we have not included hot gas bypass as an option with our Relia™ Choice and Relia™ Select products. 


In this document, we will also discuss…


Why HGBP is more commonly used on systems with:

1.     100% outside air;

2.     A variable supply of CFM;

3.     An indoor design temp below 70 degrees F; or

4.     Air supply below 300 cfm per nominal ton.

Why we do not recommend using in comfort cooling because of:

·       Cost

·       Efficiency Decline

·       Codes

·       And to be honest because we are not using it in some of our new products.

Why we are saying HGBP is not needed on Relia Choice and Relia Select products?

·       We did the testing to make sure we could get to lower CFMs.

·       We are intertwining coils to reduce the risk of freezing.

·       We put more safety and controls in place.



Some important things to remember

·       Use light commercial equipment correctly. Comfort cooling CV, SZVAV, and VAV airflow configurations are preferred and avoid process cooling applications.

·       If you have questions about a particular application, contact Light Commercial Application Support at or 877-334-9209.

·       If you are going to go below-rated minimum airflows, use a RAWAL valve installed by our Modification Center.

Be sure to download the complete paper for more insightful information.