HVACR General Purpose Switching Relays, How it Works, Troubleshooting!

In this HVAC Training Video, I show how the DPDT General Purpose Switching Relay Works. I go over the Troubleshooting of the relay with the multimeter and the voltage paths across the contact and coil. DPDT is Double Pole Double Throw. I show the resistance readings of relays with a 24v, 120v, and 240v coil. This relay is also used on Fan Center Controls and I show how they works as well! Supervision is needed by a licensed HVACR Tech while performing tasks as Experience and Apprenticeship garners Wisdom and Safety.
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⚠️ Disclaimer:
Information in this video is intended for educational purposes only. Any work related to the topics in this video should be performed by licensed technicians or by apprentices under the supervision of licensed technicians. AC Service Tech LLC is not responsible for any possible damages or injuries caused by the use or misuse of any information provided. ▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
#hvacr #hvacr #hvactrainingvideos #hvactraining #hvactraining101 #acservice #acservicetech #oil #switch #relay #relayswitch #DPDT #multimeter #voltage
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The E-Book and Paperback at our Website: www.acservicetech.com/the-book The Paperback at Amazon: www.amazon.com/shop/acservicetech Support the Channel- www.patreon.com/acservicetech Tool List- www.amazon.com/shop/acservicetech For those that are looking for the tools used in the videos: (Linked Below) Electrical Diagnosis Tools: UEI DL389 Multimeter amzn.to/2xAdaJf UEI DL479 Multimeter with temp sensor amzn.to/2jtsUbJ Magnet Jumpers- amzn.to/2PyKPQZ Alligator Jumpers- amzn.to/2PxqJXn Irwin Wire Stripper/Cutter/Crimper amzn.to/2dGTj2V Vacuum Tools: JB 6 CFM Vacuum Pump - amzn.to/2nqbvo8 CPS 4 CFM Vacuum Pump - amzn.to/2DxgPwY Appion Valve Core Removal Tool - amzn.to/2uYr8WL Appion Blue 3/8" to 1/4" Vacuum Hose - amzn.to/2uYlVyc Appion Red 3/8" to 1/4" Vacuum Hose - amzn.to/2uYg6Ro Yellow Jacket 1/4" by 1/4" 3’ hose - amzn.to/2umtcod Appion 1/4" by 1/4" and 3/8” hose - amzn.to/2Zyxzx9 Uniweld 1/4" by 1/4" 2’ hose - amzn.to/2GFov1Y CPS Vacuum Micron Gauge - amzn.to/2v1nM3O Supco Vacuum Micron Gauge - amzn.to/2v1JRiA JB Vacuum Pump Oil - amzn.to/2mGrlXy Checking the Charge: Yellow Jacket Refrigerant Gauge Set amzn.to/2aenwTq Refrigerant hoses with valves amzn.to/2aBumVI Yellow Jacket Gauge set & hoses amzn.to/2vLVkV9 Yellow Jacket 4 Port Manifold w Hoses amzn.to/2BkuGIq Digital Refrigerant Scale amzn.to/2b9oXYl Ratcheting Service Wrench amzn.to/2dGV4Nh FieldpieceSMAN360 Digital Manifold Set amzn.to/2BdoaD4 FieldpieceSMAN460 Digital Manifold Set amzn.to/2nB4Fe6 Compact Ball Valve for Refrigerant Hose amzn.to/2KUisW8 QuickDisconnect 90 for refrigerant hose amzn.to/2MMtVcg RectorSeal Bubble Gas Leak Detector amzn.to/2ckWACn Fieldpiece ST4 Dual Temp Meter amzn.to/2wc1ME3 Fieldpiece Bead K Type Temp Sensor amzn.to/2DBwKfs Fieldpiece Wet Bulb Temp Sensor amzn.to/2RRI7Tw Fieldpiece TC24 Temp Clamp amzn.to/2qHLyjZ Flaring Tools: Yellow Jacket Flaring Tool - amzn.to/2OBxGlM Spin Flaring Bits 1/4", 3/8", 1/2", 5/8", 3/4"- amzn.to/31BCs8Z Yellow Jacket Flaring Tool with Set Depth - amzn.to/2QIKsQH Yellow Jacket Torque Wrench - amzn.to/2NRR68Q Uniweld Swage and Flare Kit- amzn.to/2T55jyn Nylog - amzn.to/2MLJcch Ridgid Tubing Cutter - amzn.to/2DnjjR1 Wolverine Tube Reamer - amzn.to/2QGLyMV Swaging Tools: Manual Copper Tube Swage/Expander- amzn.to/2WRPa1M Spin Swaging Bits 1/4" to 7/8" for the Drill- amzn.to/2YQwwqS Uniweld Hydraulic Swaging Tool- amzn.to/2MlrI8m Uniweld Swage and Flare Kit- amzn.to/2T55jyn Uniweld Hammer Swage kit- amzn.to/2CzWMMU Uniweld 3/4" Hammer Swage- amzn.to/2CzXsSs Uniweld 7/8" Hammer Swage- amzn.to/2Mja5WE Uniweld Multi-Size Hammer Swage- amzn.to/2T3Cx1b Brazing Tools: Air Acetylene Torch setup - amzn.to/2aQalsb 15% Silver Brazing Rods - amzn.to/2gVLyLc Uniweld Cap-N-Hook and #2 Tip Oxy Acetylene Torch Setup - amzn.to/2STp3Fe Ameriflame Oxy Acetylene Torch Setup #1 &#2 Tip - amzn.to/2SRm3JF #2 Tip for Oxy Acetylene Torch - amzn.to/2SPDaeD Cap-N-Hook Tip for Oxy Acetylene Setup - amzn.to/2MbhpUk 40cu B Tank to 10cu MC Tank Acetylene Tank Fitting - amzn.to/2GxZZPi Nitrogen Regulator - amzn.to/2bXdR5f Uniweld NitroVue Flow Regulator - amzn.to/2GnsaAo Uniweld Nitrogen Flow Meter - amzn.to/2brvoBg Bernzomatic Trigger Start Lighter Propane/Mapp Gas - amzn.to/2vit0cv Uniweld Soft Flame Sweating Torch Setup for Acetylene - amzn.to/2DyzRD8 Flint Spark Ignitor - amzn.to/2L3P2u9 Stay Brite #8 Silver Bearing Solder and Flux - amzn.to/2XIDJsY Aluminum Braze Rods - amzn.to/2IGNMu Nitrogen: Uniweld NitroVue Flow Regulator- amzn.to/2GnsaAo Uniweld Nitrogen Flow Meter amzn.to/2brvoBg Nitrogen Regulator amzn.to/2bXdR5f Service Valve & Port Access: RectorSeal Bubble Gas Leak Detector - amzn.to/2ckWACn 25 Valve Cores - amzn.to/2L37UJU 25 ¼” Brass Port Caps with rubber O-rings - amzn.to/2GIOdD2 Brass Valve Core Tool which holds 3 valve cores - amzn.to/2GFEbm2 Valve Core Torque Wrench - amzn.to/2GHiLoD Locking Cap Universal Lock/Unlock Tool - amzn.to/2GGAoVp Locking caps - amzn.to/2GFXZ8A Ratcheting Service Wrench amzn.to/2dGV4Nh Yellow Jacket Sealright 90 Coupler- amzn.to/2LsU1V7 Yellow Jacket 1pk Compact Ball Valve- amzn.to/2uXdF18 Yellow Jacket 3pk Compact Ball Valve- amzn.to/2AiKfQe Thumb Screw Valve Core Depressor with Backseat- amzn.to/2mR0sCL Leak Detection: Accutrak VPE Ultrasonic Leak Detector amzn.to/2nFYKVe Accutrak VPE-GN Ultrasonic Leak Detector amzn.to/2Zy4IZP RectorSeal Bubble Gas Leak Detector - amzn.to/2ckWACn Other tool links can be found in the video description section. 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- www.amazon.com/shop/acservicetech

[@heatingairservices8708]

Thanks watching learning from ya for years ,,Ive got 24 + years In Love The trade 65 now hopefully 5- 10 more yrs left in me but absolutely best explanation ive ever herd on relays or powerd switches ......we appreciate ya always greatly Thanks

[@philgrant8927]

Thanks so much. I'm using one like the black one to alternate switching between humidifying and dehumidifying my piano.

[@Fict10n]

Thanks for taking the time to make these videos. As a first year apprentice, this is very helpful.

[@acservicetechchannel]

I am really glad that they are helpful!

[@abazism]

Thank you very much. You explain it step by step without skipping something.

[@fallen_rain5295]

Currently in trade school and these vids help so much better understand simple devices

[@l.crossjr]

Hands down the best hvac channel. Very detailed. Thank you

[@acservicetechchannel]

Thank you very much L Cross Jr, glad to help!

[@chiplaurn8175]

Where was this video 16 yrs ago? 😂 Great vid!

[@williampaul8979]

Thanks Craig! Hands down one of the best, if not the best, informational HVAC/R channels on KZbin. Really appreciate all the effort you put into making these great videos! Will soon be subscribing to Pateron as well! Thanks again!

[@acservicetechchannel]

Thank you very much for your comment William and that would be awesome, thanks!

[@levisnyder6050]

How do I subscribe to Paterson?

[@emanuels.6541]

Great explanation of relays and their troubleshooting steps. Thanks much

[@acservicetechchannel]

Thanks Emanuel!

[@nando5302]

Great work Craig. Always look forward to your videos. Maybe one of these day you should do a vehicle stock video.

[@acservicetechchannel]

Nando 530, thanks for letting me know what you would like to see!

[@reza49363]

Your videos are so helpfully, God bless you

[@acservicetechchannel]

Thank you very much RA! May The Lord Bless You Too!

[@sylvesterguerrero2848]

I liked all your good information!!!

[@marshallstephens7356]

Great video! Thanks so much

[@TDS516]

very well explained thanks for the post

[@PBS-nm1uu]

another great video please keep them coming

[@acservicetechchannel]

Thanks, will do!

[@workinprogress4579]

Great video! Is there a video on how to wire these into the system?

[@abrahamcontreras892]

When you want to check to see if a relay ( no power) is good you check for continuity but you check for ohmns at the relay coil?

[@joemartinez7619]

Thank you so very much.

[@acservicetechchannel]

Glad to help Joe!

[@user-kt2hb8xr3p]

شكرا اخي دائما ممير العمل

[@acservicetechchannel]

دائما سعيد للمساعدة! ، شكرا! Always glad to help! Thanks!

[@angelhinojosa3005]

You are the best! Thank you!

[@acservicetechchannel]

Glad it helped!

[@reza49363]

Thank you Craig 🙏🙏🙏🙏👌👌👍👍

[@acservicetechchannel]

Glad to help RA!!!

[@tylercarver7924]

Would love for you to explain a situation in where you would have the fan in the normally open position, and what would be also hooked up in the normally closed position. Also, a situation of your choice on where you would need a relay on a unit and how you would use it to make the job easier. Thanks

[@acservicetechchannel]

The fan and other loads are usually always on the NO contacts. The NC contacts are used less often.

[@chrisdeanndavison3626]

Older air handlers use both NO & NC a lot (they work similarly to the fan center control in the video) The fan lead would be connected to terminal 1. Power from a heat sequencer would connect to terminal 2. Since 1 to 2 is NC, the blower would run when the heat sequencer was powering a heating element. Then, line power would connect to terminal 3. Lastly 24 volt C & G would land on the coil connections. When the thermostat has a fan call, G is powered, and the relay then closes the NO circuit between 1 & 3. Power is sent to the blower. Using a similar method, you can even hook different blower speeds up this way. If you wanted a high speed on cooling, hook the black wire from the blower to terminal 4, and the line power that was connected to terminal 3 in the earlier example, would instead connect to terminal 6. Connections at 1 & 2 would be the same as before.

[@rafaellara4122]

@@chrisdeanndavison3626 I haven’t seen units with the tan running on the NO contact yet. I’m pretty new at this though

[@chrisdeanndavison3626]

@@rafaellara4122 Keep asking questions and watching this guy's channel. This would be much easier if I could draw a diagram. But, as stated before, the fan lead is connected to terminal 1, which in other cases would be called Common. Line voltage is connected to terminal 3, which is a Normally Open contact. This is the most typical wiring of fan relays. The fan circuit needs to be Normally Open unless there is a call for the fan to run. In which case the Normally Open contacts will close, causing the fan to run.

[@macster1457]

I just got a fan relay replaced on my AC unit. Every time the AC turns on, it makes a loud click. I don't remember the old relay being so loud. Is this normal?

[@RC-Heli835]

Hi Craig! Whats the best way to interrupt the G fan when W calls for heat? I have a 90-340 relay that powers up my inducer motor, pressure switch and igniter and all the terms are being used when W calls but when its off could G be routed through the normally closed switch? Or better to use a second relay? Currently G turns on the AC fan for Heat, AC and Fan only. Someone has wired the fan up up with one 90-370 relay. Its has the Hi fan and fan limit switch on the normally closed 2nd from top left pin and the Hi AC fan on the normally open switch top left which causes my fan limit not to function when the unit kicks on. Instead the AC fan kicks on soon as W calls for heat but then when the thermostat is satisfied and powers off the fan relay the normally closed part of that switch brings the fan limit into play where it then does not shut the fan off until the heater cools down. This furnace is so old it does not have a circuit board or flame roll out switches.

[@hozerhvac4406]

Thank you

[@acservicetechchannel]

Thank you for your support!

[@matthewholmes8638]

Is there anyway to tell if I need a 24v or 240v relay? I have a old electric furnance and the label came off the original.

[@reza49363]

You are emazing👏👏👏👏👍👍👍

[@acservicetechchannel]

I am glad that you are enjoying the videos, thanks!

[@saablife6009]

Question I'm relocating to America Indianapolis from England I'm a qualified air conditioning and refrigeration engineer with a City and Guilds f gas qualification what test would I need to do in America or could I transfer the qualification ?

[@jaym48]

...what should my ohms reading be across the coil points for my R82222B 1067.....i get 0.06 ohms when on the 200 ohms scale so i guess that means 12 ohms. does this mean a good or bad relay. i assume you realize i know nothing about electrical circuits...any help appreciated

[@phillipborbon2059]

Is there a video to know how to check for a cut low voltage wiring? Got a practical monday and need some info.

[@acservicetechchannel]

Are you talking about low voltage wiring? Look up "acservicetech low voltage 24v wiring, thanks!

[@phillipborbon2059]

@@acservicetechchannel Yes, it is voltage wiring and have been looking at your channels, but asked to hopefully you know specifically what video I should go for. Btw when troubleshooting should you touch one end of a wire to another or a piece of metal to one end of the wire to see if it is an opened line?

[@JGR088]

Great 👍 👍 👍 video..

[@acservicetechchannel]

Thank you 👍

[@johnnyjackpots505]

Your a bad ass bro!!!

[@luiscruz0530]

Great video, if my original Relay is (8FLA 48LRA 277VAC) can I replace it by (8FLA 48LRA 250VAC) ? thanks

[@chrisdeanndavison3626]

Without more information, it's hard to say. My best guess is that it would be ok. However, the general rule of thumb is to NOT replace something with a lower-rated product.

[@AG-tg9in]

Your hands are too well taken care of for being in the trade lol my dads hands are scared same here old burnt couple scars lol good video my friend :)

[@marcelangers9953]

Is this n your books? And how many books do you have out?

[@acservicetechchannel]

I just have the one refrigerant book out right now. The full outline is available on the website www.acservicetech.com . That includes everything needed to prepare a system for refrigerant, refrigerant charging, and troublehooting using superheat and subcooling, delta t, and I also go into airflow and components, thanks! Look up "acservicetech hvac book" for a video on it, thanks!

[@levisnyder6050]

Do you stand by this model meter? (DL479)? I just got the DL479. Does this meter hold up like the older model UEI 379B? Just doesn't seem as durable. I was a bit disappointed but I wanted to gather your input on the meter. Likes/Dislikes

[@santoshgurung3584]

Show switching realy diagram

[@tomwalker9184]

Would like to see you use actual working motor

[@acservicetechchannel]

Thanks for letting me know Tom!

[@waytospergtherebro]

Why do literally all the HVAC guys insist that "acrosst" is a word?