Defrost Mistake That Sends Refrigeration into a Head Pressure Death Spiral - Julian Finbow Part 2

In this episode of the HVAC Know It All Podcast, host Gary McCreadie talks with Julian Finbow, RSE, Service Tech Support at Swegon North America, and Principal at Finbow Inc., about the different types of defrost methods used in commercial refrigeration systems. Julian explains how electric defrost, hot gas defrost, and cool gas defrost work, along with their advantages, challenges, and energy use. The conversation also covers defrost termination controls, mechanical and digital defrost time clocks, managing head pressure in large rack systems, and real service experiences showing how adjusting defrost schedules can improve temperature control and reduce frost buildup in refrigeration equipment.

Gary and Julian discuss the different defrost methods used in commercial refrigeration systems and how each one affects performance and efficiency. Julian explains how electric defrost, hot gas defrost, and cool gas defrost work, along with their benefits and challenges. The conversation covers defrost termination controls, mechanical and digital defrost time clocks, the importance of head pressure during hot gas defrost, and real field examples showing how changing defrost schedules can improve temperature control and reduce frost buildup in refrigeration systems.

Expect to Learn:

• How electric, hot gas, and cool gas defrost systems work in commercial refrigeration.

• Why defrost termination controls help improve efficiency and reduce unnecessary heating.

• How mechanical and digital defrost time clocks control refrigeration system operation.

• Why proper head pressure is important for reliable hot gas defrost in large systems.

• How adjusting defrost schedules can improve temperature control and reduce frost buildup.

Episode Highlights:

[00:00] - Sponsor: Factory Direct Filters ad

[00:42] - Intro to Julian Finbow, RSE in Part 02

[02:27] - Electric Defrost: Pros, cons & common drain heater failures

[06:38] - Defrost Types: Cool gas defrost & energy efficiency comparison

[08:16] - Defrost Termination: Using sensors to end defrost early & save energy

[11:56] - Head Pressure: Managing pressure during hot gas defrost in large systems

[14:08] - Troubleshooting: Adjusting defrost cycles (4 to 6 shorter ones) to fix temperature spikes

[17:02] - Increasing defrost cycles to fix -40°F freezer issue; closing

This Episode is Kindly Sponsored by:

Cintas: https://www.cintas.com/hvacknowitall

Cool Air Products: https://www.coolairproducts.net/

Factory Direct Filters: https://www.factorydirectfilters.com/

SupplyHouse: https://www.supplyhouse.com/tm
Use promo code HKIA5 to get 5% off your first order at Supplyhouse!

Follow the Guest Julian Finbow, RSE on:

LinkedIn Profile: https://www.linkedin.com/in/julian-finbow-rse-1048038b/

LinkedIn - Swegon North America: https://www.linkedin.com/company/swegon-north-america/

LinkedIn - Finbow Inc.: https://www.linkedin.com/company/finbow-inc/

Website - Swegon North America: http://www.swegonnorthamerica.com/

Follow the Host on:

LinkedIn: https://www.linkedin.com/in/gary-mccreadie-38217a77/

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