Sign In

Search HVAC School

Search In:

Event Videos Tech Tips Apps Books Podcasts

No Bull Forum
Resources
Content
- Start
- Podcasts
- Videos
- Social Media
- Tech tips
- Tech Tips Library
- Quizzes
Courses
Events
Shop
Partners

Search HVAC School

Search In:

Event Videos Tech Tips Apps Books Podcasts

English▼

+

Chinese (Simplified)

Sign In

BACK

Subscribe to our Youtube channel

Stuck Contactor Issue

December 15, 2020

Comments

Sukhpal @daniellew

Curious to know as to why it gets stuck

7/15/22 at 06:10 AM

Curious to know as to why it gets stuck

Files:

To leave a comment, you need to log in.

Most popular videos

view all

Check out our most recent video

More HVAC School videos on YouTube

Our latest Podcast

HVAC School – For Techs, By Techs

HVAC School – For Techs, By Techs

Real training for HVAC ( Heating, Ventilation, Air Conditioning and Refrigeration) Technicians. Including recorded tech training, interviews, diagnostics and general conversations about the trade.

The A2L & Refrigerant Transition – Short #302

byBryan Orr

In this short podcast episode, Bryan and Roman talk about the A2L & refrigerant transition again, particularly sensors on R-454B and R-32 equipment.

Since the beginning of the A2L transition, we have seen the equipment evolve and begin requiring accessories, including refrigerant sensors and blower recirculation systems (BRS) or dissipation boards. In a BRS, the blower turns on and dilutes the refrigerant in the space to keep the refrigerant concentration below the lower flammability limit (LFL) and prevent ignition. Some systems may also have isolation valves and pump themselves down whenever the A2L sensor trips. These sensors use MOS technology, which measures gas changes by tracking electrical connectivity shifts; they have limited lifespans and can become corrupted over time.

In the field, you may notice a running fan without the outdoor unit running. Some diagnostic boards might give you error codes, but if you don’t and don’t have 24V when you troubleshoot the issue, you may want to check the sensor. The sensors could be wet, tripped by VOCs, or even have been cut out.

This episode contains embedded sponsor messages from Refrigeration Technologies, Carrier, TruTech Tools, Fieldpiece, and Filtrete.

Resources

A2L Dissipation Boards and Leak Sensors
HVAC School calculators
Submit a podcast question
Learn about the GRIT Foundation

Purchase your tickets or learn more about the 8th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

The A2L & Refrigerant Transition – Short #302

Search Episodes

The A2L & Refrigerant Transition – Short #302

09/08/2026

Bryan Orr

Invented For Techs, by Techs: Inside Refrigeration Technologies’ “The Lab”

09/03/2026

Bryan Orr

The Ethics of IAQ – Testing vs. Remediation Conflicts – Short #301

09/01/2026

Bryan Orr

Is 400 CFM per Ton Always Right? w/ Ty

08/27/2026

Bryan Orr

The MERV 15 Filtration Physics – Short #300

08/25/2026

Bryan Orr

Tips for Being On Call w/ Ty

08/20/2026

Bryan Orr

The Florida “M-Word” – Legal Boundaries & Tech Communication – Short #299

08/18/2026

Bryan Orr - A/C Trainer

Becoming a GRIT Host or Mentor w/ Leilani

08/13/2026

Bryan Orr

Behind the Drywall – The Psychrometrics of a Hidden Moisture Failure – Short #298

08/11/2026

Bryan Orr

HVAC Education. What NOT to Do w/ Jim F., Roman B. and Craig M.

08/06/2026

Bryan Orr

Search Results placeholder

Check our latest Tech Tips

Why is 240V called "Single-Phase"? Flowing Nitrogen? Make Sure You Purged First What is a GFI?

VIPER SNIPER UNIVERSAL AEROSOL TRIGGER SPRAYER

VIPER SNIPER UNIVERSAL AEROSOL TRIGGER SPRAYER The Viper Sniper is an ergonomic trigger sprayer that fits all standard aerosol cans. Designed for comfort and control, it reduces finger fatigue and delivers a smooth, consistent spray, especially in those hard-to-reach areas. Features quick-attach side clips for easy, secure use. Compatible with all standard aerosol cans —including Viper Aerosol Coil Cleaner and Coil Coating Spray. Fits Any Aerosol Can Full Hand Ergonomic Grip Easily Clips On and Off 2 Sprayers per pack

VENOM PACK CONDENSER PURE CONCENTRATE COIL CLEANER

VENOM PACK CONDENSER PURE CONCENTRATE COIL CLEANER Venom Pack Condenser Cleaner is a high foaming pure concentrate liquid designed to tackle the toughest soils. The proprietary blend of specialty detergents will liquify heavily embedded grease and grime to restore heat transfer and increase the efficiency of the coil.

Viper Condensate Pan and Drain Treatment

Viper Condensate Pan and Drain Treatment Viper Condensate Pan and Drain Treatment is a sprayable gel. It coats the pan, p-trap and drain piping with a lubricative film to improve flow and prevent future soil adhesion. The slow dissolving enzyme gel will outperform and outlast conventional tablets and strips.

Nylog Blue Gasket -Thread Sealant for AC/R Systems

Nylog Blue Gasket -Thread Sealant for AC/R Systems One drop of Nylog on your rubber hose gaskets prior to attaching your core tools, hoses or vacuum gauge will assure that things do not bind or leak during evacuation. Derived from refrigeration grade lubricants. Non-hardening, non-drying fluid which bonds tenaciously to many different substrates. Typically, one drop of Nylog can be stretched about three feet before breaking.

NAVAC

Find out more about the Innovative NAVAC line of Vacuum Pumps

AHR Expo

Join us for HVACR's Main Event

Santa Fe

UEI

To continue you need to agree to our terms.

Terms and Conditions

Yes No

The HVAC School site, podcast, and tech tips are
made possible by generous support from

Interested in an HVAC career?

Find a local trade school

Resources

Calculators
Tool list
Apps
Great Books
Software and Business
Other Resources we like
Unconformed

Content

Start
Podcasts
Videos
Social Media
Tech Tips
Quizzes
Courses

Events

8th Annual HVAC/R Training Symposium
Upcoming Events

Partners

Partners
Carrier
Copeland (Emerson)
Fieldpiece
NAVAC
Refrigeration Technologies
Santa Fe
TruTech Tools
UEi Test Instruments

Get Tech Tips

Subscribe to get free tech tips

Email Address

First Name

Terms and conditions & Privacy Policy
Reuse License

©2026 - HVAC School | All rights reserved

Loading Comments...

Write a Comment...

Email (Required)

Name (Required)

Website