Troubleshooting all HVAC CIRCUIT BOARDS! Methodology and Procedures Used in the Field!

Share it with your friends Like

Thanks! Share it with your friends!


In this HVACR Training Video, I show my Methodology for Diagnosing Problems with any Type of HVAC Control Board! I give Tips, the Approach, a Sequence for Testing, Multimeter Test Locations, and What to Look Out for When Troubleshooting Intermittent Issues! Supervision is needed by a licensed HVACR Tech while performing tasks as Experience and Apprenticeship garners Wisdom and Safety.

My Paperback and E-Book:
My Paperback:
Support the Channel:
Tool List:

Check out our HVAC Calculators at
Check out our newest full articles at
Try our new quizzes! Do you have what it takes?
Check out our Podcast!
Follow us on Facebook!

Related Videos
Troubleshooting the Furnace Control Board IFC to Test if its BAD:
Air Handler Control Board Operation and Troubleshooting!:
HVAC Control Board Operation for Troubleshooting!:
DEFROST Control Board Wire Terminal Functions:
How the Blower/Fan Relays on a Furnace Control Board Work!
How an Air Handler WITHOUT a Control Board Works! AC and Heat Pumps!:
Gas Furnace Ignition Control Modules!:
Air Handler Fan Delay Board! Explained & Tested!:
Wiring a Heat Pump Thermostat to the Air Handler and Outdoor Unit! Functions, Terminals, Colors!:
How an Air Handler & Heat Pump Work & are Controlled by 24v Thermostat Wires!:
Thermostat Wiring to a Furnace and AC Unit! Color Code, How it Works, Diagram!:
Heat Pump Thermostat Wiring Explained! Colors, Terminals, Functions, Circuit Path!:
Thermostat Wiring Diagrams! 10 Most Common!:

Electrical Diagnosis Tools:
UEI DL389 Multimeter
UEI DL479 Multimeter with temp sensor
Magnet Jumpers-
Alligator Jumpers-
Irwin Wire Stripper/Cutter/Crimper

Vacuum Tools:
JB 6 CFM Vacuum Pump –
CPS 4 CFM Vacuum Pump –
Appion Valve Core Removal Tool –
Appion Blue 3/8″ to 1/4″ Vacuum Hose –
Appion Red 3/8″ to 1/4″ Vacuum Hose –
Yellow Jacket 1/4″ by 1/4″ 3’ hose –
Appion 1/4″ by 1/4″ and 3/8” hose –
Uniweld 1/4″ by 1/4″ 2’ hose –
CPS Vacuum Micron Gauge –
JB Vacuum Pump Oil –

Checking the Charge Tools:
Yellow Jacket Refrigerant Gauge Set
Refrigerant hoses with valves
Yellow Jacket Gauge set & hoses
Yellow Jacket 4 Port Manifold w Hoses
Digital Refrigerant Scale
Ratcheting Service Wrench
FieldpieceSMAN360 Digital Manifold Set
FieldpieceSMAN460 Digital Manifold Set
Compact Ball Valve for Refrigerant Hose
QuickDisconnect 90 for refrigerant hose
RectorSeal Bubble Gas Leak Detector
Fieldpiece ST4 Dual Temp Meter
Fieldpiece Bead K Type Temp Sensor
Fieldpiece Wet Bulb Temp Sensor
Fieldpiece TC24 Temp Clamp

Flaring Tools:
Yellow Jacket Flaring Tool –
Spin Flaring Bits 1/4″, 3/8″, 1/2″, 5/8″, 3/4″-
Yellow Jacket Flaring Tool with Set Depth –
Yellow Jacket Torque Wrench –
Uniweld Swage and Flare Kit-
Nylog –
Ridgid Tubing Cutter –
Wolverine Tube Reamer –

Swaging Tools:
Manual Copper Tube Swage/Expander-
Spin Swaging Bits 1/4″ to 7/8″ for the Drill-

Refrigerant Leak Detection Tool:
Accutrak VPE Ultrasonic Leak Detector

Shop through Amazon! Your Purchases through Amazon provide a means for channels such as mine to earn advertising fees from all purchases after clicking through. Prices are the same as normal.

  • Rating:
  • Views:721 views
  • Tags:
  • Categories: HVAC


Zunar_J5_9 says:

Just got the Refrigerant Charging and Service Procedures book in, love it!

pardeep kumar says:

TNice tutorials is video is amazing! thanks for posting.

Elliot Ramos says:

You are a bless to us… Thanks.

edilson serafim says:

Craig you are really good thank you for being you I have grown so much and getting better with my techniques watching your videos.

edilson serafim says:

Craig you are really good thank you for being you I have grown so much and getting better with my techniques watching your videos.

Raul Nunez says:

Thank you for sharing your knowledge I really appreciate the videos that you are making even if English isn't my first language everything is well explained even I understand them 😁👍👍

Leo Jung says:

Hi Craig I have a question about my HVAC. My Ac works for about a hour whenever I take out circuit board and put it back. I constantly have to do that process to stay cool this summer. I might think you might know the solution.


I just want too tell u thank u for u videos n ur Knowledge u sharing on ur channel highly appreciated keep em coming

Art Beach says:

Awesome channel.i was starting a wiring book myself .

Quinn Math says:

With your help over the years I am now the lead tech out of 30 guys.

Alejandro Morales says:

I already bought you book

علي الشيخ says:

Great job, thank you brother. You are so talented

phs84 says:

Hi, Long time viewer just a shout out from Aust. I am in the Hvac industry over here and find a lot of your content very informative and helpful. Keep up the good work

Johnny Valdez says:

Can you do a video on how to size a home and duct designing?

Brian B says:

Been waiting for this video. Thank you

Randy Bennett says:

This a very good basics tutorial I like the way you have explained the different boards. But there are multiple issues that go deeper and one that comes to mind is loosing the common connection in the board. Very rare but happens and difficult to read if you aren't open minded for that problem. Thanks for your videos.

onlyu Lee says:

I have a question if a piston oversize would that lower or higher temperature difference..

Crispin Plariza says:

What is the right resistance when testing the thermostant sensor/and ambient temperature.

thecurious says:

Hi Craig, thank you for your videos 👍 I have a question if you dont mind 🙂 We are supposed to use exact run capacitors for the motors. But amrad turbo200 capacitors have two 5 uf terminals used one is for 5/4 uf (dmm showed 4.7uf) and the other for 5/6 uf (dmm showed 5.7uf). I spoke with them, they said there is no effect on the motor performance/reliability if I use 5/4uf for 4 uf capacitor, but it is almost 20% difference. Some old ac's use 35/3 or 35/4 capacitors, so I am curious how it is safe to use 35/5 instead of them 🙂 I would appreciate if you could explain it. thank you. 🙏

Jose says:

Ran into this issue this year where I used my ECM tester to test the module of the blower because it wasn’t running and it ran when I used my tester. So I replaced the control board and surprisingly still had the same issue. Replaced the entire motor and module and then it started to work. Most of the time it will be the board if it turns on with the ECM tester but now I know that the module can still be bad even if your ECM tester turns it on. It was on a Lennox communicating air handler. Tech support also said this happens but very rarely and sometimes you have to replace the board and module at the same time for it work.

Si J says:

I’m a new technician. Your channel is really helpful thank you so much razani says:

great video as always.

kousaka san says:

I completely disassembled my main ac fan and motor thinking it was the motor. Tested it by connecting it to my second ac and it worked. I compared the two main boards using a voltage meter and found that the positive output for motor didn't have power. I ordered a new board thinking the relay was bad. Before the board came I decided to remove the old board. Turned it over and found a large black circle where the solder around the motor out had vaporized. I soldered it and it worked again. Now I have a spare board…. lol. I had stage 3 cancer and was going through chemo at the time. I blame chemo brain for not checking the board first…

Oscar Contreras says:


Zizo Boss says:

Thanks a lot for your videos

Keovong Vilaykeo says:

Count thanks you enough great content much appreciated dedicated for your hard working

Alex says:

You can also test your inputs and compare your outputs,
ie i had a board with a bad blower motor relay.
checked for juice coming into the relay and juice coming out(manually actuating the heating circuit because its NC.
jumped g to r, no switchover. tossed in an external blower controller (basically relay with timers), bam

David B says:

Craig, i have your books, big fan, however, your books are heavy on refrigeration aspect, and not the various troubleshooting of electrical issues. I think if you wrote a book on this, it would be a big winner. The only issue I see is that the electronics are in a higher stage of change, so updates would be more frequent.

Phil's Hvac says:

Your YouTube channel should be a prerequisite for new technicians or kids in school. If you’re new and you’re not subscribed to Craig’s channel then you’re missing out. There’s a wealth of free information that you can’t get anywhere else

Write a comment