Can a Relay replace a Circuit Board?? | Understanding HVAC Electrical Concepts

After being asked about switches on circuit boards and switches on a relay, I decided to replace a Goodman fan board with a 90340 relay. As an HVAC tech I don't want you to think that this is the norm for any job. I am simply doing this to demonstrate that a switch is a switch and as long as you UNDERSTAND what you are doing you can easily master the concepts of a circuit board.
I think that this field has a lot of memorizing going on and it hasn't converted to learning yet. I went through it myself but I put in the time to learn the concepts needed to understand what I was doing and be able to think through problems while troubleshooting. It is a process.
I hope that this might show someone in the trade (not a homeowner) how relays haven't gone away. They are still there but incorporated into the circuit boards which have become so common in the equipment we use today.
*please do not say that I told someone that you should do this, I recommend replacing OEM parts always.
00:00 Intro
03:25 Replacing Circuit Board with 90340 Relay

[@alfonsobenitez8574]

Thank you John. I am 68 yo retired HVAC. Always enjoyed refreshing my mind by listening to videos, i have been working for over 16 years. Still do a job here and there, i enjoyed your professionalism and how you take your time to explain in details. Thank you again.

[@johnjennings487]

That's awesome. I don't think we can ever retire from HVAC...someone who knows us will always call on the weekend! Thanks for checking it out.

[@robc2682]

I love how you explain things very well. Thank you for sharing all your knowledge

[@johnjennings487]

There is a lot to learn and wrap your mind around. I hope it helps. Thanks for watching.

[@arthurjeyes5988]

With the current 2-3 week lead time on so many high end circuit boards and electronic fan motors, this is an important thing to know how to do. Not to mention some of the ECMs are cresting $1000

[@johnjennings487]

Yes. Between the cost and the wait time it is important to understand what you can do for a customer. If you present it to them, explain it, and they are ok with it...go ahead. I think a lot of younger techs maybe don't feel as confident in the basics they learned. I like thinking about some of these situations just to get my mind going. But I do try to replace OEM whenever possible just so there isn't as much headache.

[@johnjennings487]

OEM is always the way to go in my opinion as well. But some guys I know look at circuit boards like they are aliens or something. I just try to point out that you can still check them using the basics.

[@oscarmiranda2000]

Great video, I really enjoy how simple and clear you demonstrate.

[@TerryRGraham]

A fire inspector in Farmers Branch, Texas, made us do that to a bunch of Goodman air handlers during construction. Much arguing took place between her and her boss, but they still made us do it. They wanted the blower to shut off instantly in case of a fire. No other fire department or city has ever made us do that. To be clear, they didn't tell us to put a relay in, and I doubt she or her boss knew what a relay was, but the order was to make the blower stop instantly, so that's how we did it.

[@johnjennings487]

Had something similar here too. The package units had blower motors that had delay turning off. I think it was some type of ECM motor...anyways, the fire inspector didn't go for it. Had to go and install contactors in the units so that the fire detector would kill power instantly.

[@luiscastro740]

Bluon keeping it real ,it's nice to see u guys do well,and keeping the hvac community in check

[@johnjennings487]

Thanks.

[@techfive7202]

I can't say thank you enough. Like you said in your last vid, power in from the right. All makes sense now

[@johnjennings487]

Just got to think it through and know what you want to make happen.

[@hitssongs8263]

Great information, I was able to understand all what he was explaining, this is really helpful

[@johnjennings487]

Thanks.

[@alfredhines505]

Thank you Sir, for the knowledge and the understanding. Before i have a problem understanding where to put the line and the load. U make it real easy i think i fully understand it now.

[@johnjennings487]

Thanks.

[@jollyscaria1922]

Under stand play lest mad mind is bad jobes super str mind why som allpass way

[@russelldavis637]

Great Video John

[@chriseh09]

Awesome! Great job!

[@janicesmyth2183]

What a great channel! I wish I was young enough to get into hvac! Thank you for sharing your knowledge!

[@johnjennings487]

Young enough? Never too old!

[@janicesmyth2183]

​@@johnjennings487 I'm in my 80's and would do it if the basket on my walker could hold more tools. I look for video's like yours to share with my grand kids. One is an hvac apprentice.

[@milo6373]

@@janicesmyth2183 😸 , too funny , that's the we spirit 👍✌️🙏☝️💪

[@pipi7731]

Good video and learned a few things from it. Thanks

[@MrWaynesea]

We appreciate your knowledge, experience, and support.

[@johnjennings487]

I can give you support...some people gig me a little on the knowledge and experience!! Thanks for commenting. I appreciate it.

[@viper22304]

Awesome video!!! Thanks for sharing.

[@johnjennings487]

Thanks.

[@BARR8323]

Great video, the only thing I heard you mentioned was the wire on terminal 3 was carrying 240v, however it’s only 1 line of the 240v, so it’s carrying 120v to complete the circuit. See time stamp 6:27. I understood what you meant but newbies might get confused. You got my subscription thanks.

[@johnjennings487]

That is correct. Occasionally I will fall victim to my own mind. The guys I have in a class starting out know that the main power supply to the unit is approx. 240V so I "speak their speak" sometimes to get the point across. Of course I still have to go back over it with them and make sure they remember that there are 2 sides of power and that they add up to the 240V. Appreciate it. Thanks for watching and commenting.

[@robertcherry4971]

Actually he was correct and did not even know it.It is 240 going north then 240 going south .This is alternating current.It is only 120 respect to ground.That is why you do not need a neutral for a 240 volts or kkkkkpower feed one wire is carrying 240 the other serves as the return(neutral) alternating at 60 times a minute(frequency)this is your sine wave.The tap of the ground is at the center tap of the transformer (POCO’s) transformer and cuts the voltage in half when measured respectively to ground… UNDERSTAND WHST I AM CONVEYING?

[@johnjennings487]

I will have to read over it a few times and draw myself a picture. This is what i tell people about electricity--electricians have their power, hvac guys have their power, electronics guys, etc. and i think we all use, apply, and describe it differently. To me, that is what messes so many young techs up. Ask 10 people about electricity and get 11 different answers. But I like to see how people think and try to understand their perspective. By the way, what is POCO?? Is it a manufacturer?

[@officerkrupke4966]

@@robertcherry4971 Tell that to a jackass and he will kick you. So when the cop stopped you for speeding, did you offer the excuse that you were only going thirty mph up the hill, than thirty mph down the hill.lmao.

[@robertcherry4971]

@@officerkrupke4966 no I ask them am I being detained.. LMFAO

[@soloch69]

Great video keep them coming, Love it thank you for the info

[@johnjennings487]

Thanks for checking it out.

[@OrlandoFL50]

Very helpful sir!

[@rafaelsalcedo6350]

Respect for the knowledge and sharing it

[@johnjennings487]

Thanks. We all have got a lot to learn and a lot to share.

[@SmokyRibsBBQ]

I worked on old furnaces years ago prior to printed circuit boards being used in furnaces. I remember that they were set up with sequencers to energize the blower first on before the electric elements and last off after the elements turn off. Kinda wish things would go back to that simplicity. Good video, enjoy your videos.

[@johnjennings487]

I got wire strippers! It can happen.

[@jeanjeanbaptiste4013]

John you doing a great job

[@johnjennings487]

Appreciate it.

[@maxtorres7942]

Very good advice, thank you.

[@edgar20109]

Great video 📹 thanks for teaching!!

[@johnjennings487]

Thank you for watching.

[@hkhsm359]

very nice video . great knowledge and explaining thanks for sharing

[@johnjennings487]

Thanks. It was more for the thought process than anything.

[@edinaldomanuel8329]

thank you mister John, i really appreciated your presentation, ill make notes for next job...cheers

[@johnjennings487]

Thanks.

[@erlinvalle1163]

Great video man you saved me this time

[@ramonnogueras1267]

Very good information.

[@frankduarte7109]

Great video man

[@johnjennings487]

Thank you.

[@mosadhana5815]

Outstanding!! Thanks.

[@johnjennings487]

Thank you.

[@kevin_1979]

Best video ever seen on KZbin.

[@johnjennings487]

Awww. Thank You. You're the nicest person ever on KZbin.

[@principeazteca2000]

i love it..thanks John i just subcribed to your channel...thanks again..keep up the good work..i'm your new fan

[@donaldcarter4324]

Great tutorial 👌

[@johnjennings487]

Thank you.

[@ApartmentMaintenance]

Great video! Definitely works in a pinch & good to know how to wire it up. I agree with you on using OEM parts for a customer. Thanks for sharing 👍

[@johnjennings487]

I always suggest OEM. It's too easy to remember. Thanks for watching!

[@gotchaplumber]

Good info!

[@Eddy63]

Good little demo ... Thx ...

[@johnjennings487]

Thanks.

[@noealeman8527]

Good explanation!!

[@johnjennings487]

Thanks.

[@cloverjake]

Fine video and a good review on some earlier learned skills…

[@johnjennings487]

Thanks.

[@16480287]

In my mind I was thinking if I have a problem with my furnace and it showed a bad circuit board that using the 90-340 relay I could replace the board ! and guess what your training session not only proves it but shows how. I already had my mind set on doing just as you did, Thank you for setting me straight, I am a retired aircraft/automotive mechanic and my mind is always open for new ways of doing things. I am 86 years old and this keeps my mind active. I have never had a service man on anything I own , I either fix it or break it then buy a new one !

[@johnjennings487]

I like the way you think. Keep your mind active. Broke plenty of stuff and the wife liked it because she got a new one. Sometimes she thought she was getting new and I fixed it to her disappointment!

[@jeffreyhill3960]

Industrial electrician here….there are off delay relays, on delay relays etc. both with n/o and n/c involved. these can be ordered ahead and shelved…way better than simple boards that always give up at the most inappropriate times…..

[@Ryan-ok2xr]

thank you! needed something until I get a part in and this is perfect

[@johnjennings487]

If it is just a blower board you might end up liking the relay better!

[@Ryan-ok2xr]

@@johnjennings487 makes sense thanks!

[@jessmcclain7923]

Thanks you helped me out so much.

[@johnjennings487]

Glad to hear. Thanks for checking out the video.

[@angelzucchet8543]

Excellent your video thanks. 😄

[@gilbertovillalpando7365]

Thank it’s really helpful

[@codykruies3414]

Ty for the help!

[@johnjennings487]

Thanks for watching.

[@simmonsjr25]

Very good information. Sounds like I heard this before in somebody's class. 🤔

[@johnjennings487]

I know, I know. But you wouldn't believe how many guys ask me about that 1 little relay and how to hook it up! Thanks for watching as always.

[@anvibrimel41]

Awesome video thanks

[@johnjennings487]

Hope it helps a little

[@stevencarrillo3615]

Grateful that you showed me how to do get a customer system up and running for a bit while waiting for the replacement parts that was a lot of help

[@johnjennings487]

Thanks. I think we can use relays sometimes to get us by for a day or two while waiting on the parts to arrive. Of course without butchering up the wires and function of a unit. Glad to hear it helped.

[@jorgeaguila6774]

Great job TNX you kindly🤙🏽

[@johnjennings487]

Thanks. I appreciate it.

[@ace8237]

You make it look easy 🤣 awesome video man

[@johnjennings487]

Thanks...lots of editing!

[@matthosseini4194]

Thank for awesome information 👏

[@johnjennings487]

Thanks.

[@missionuluna5837]

Thanks brother for sharing this videos 👍🙏👏🇵🇬

[@HsingSun]

Thank you for your video. Question: What is AC voltage between Red and Green wires at the Solid State Time Delay should be?

[@johnjennings487]

The red is 24V going into the solid state timer "switch". If i check it to green going out of the "switch" when the relay coil is energized it would be 0 volts (same leg of power). I would think it should be 24 volts if the relay coil is not energized.

[@HsingSun]

Thank you for your video. Question: Is that control-board included Time-Delay and Fan-Relay?

[@johnjennings487]

Yes. It has about a 7 second delay before the fan comes on and then approx. 1 minute when it shuts off.

[@Rayram555]

That is clever you have great knowledge and your imagination is genius.

[@rubenvergara6374]

Thank you this video is great

[@johnjennings487]

Thanks.

[@petmogulsupplies6631]

thanks for the video

[@johnjennings487]

Thanks for watching.

[@SBB1955]

Fantastic info! Would you be able to supply a wiring diagram?

[@mauricioskippy1996]

Gracias señor

[@1971omi]

Can you use delay on Make/ Break to fix the problem with relay for fan timing?

[@johnjennings487]

Sure. I will have to see if I have one of those and maybe update the video. Thanks for watching.

[@jugears1081]

John, I have a Goodman AC unit which is 25 yrs old and has been a wonderful unit but occasionally the blower inside can't start. It just rolls slowly and if I switch the on/auto blower switch a few times it will start. The fan motor rolls fine when it's off. I changed the thermostat. That wasn't the problem. It has done this for 2 years. I am considering putting a 90-340 relay around the blower board relay. Last week, for the first time, the blower did not turn off after the compressor quit. What do you think? I write you because you are an excellent teacher. The best I know of. Please,Tell me what to test. Richard

[@alfonsobenitez8574]

Excellent explanation, I am retired state licensed, but just staying sharp.

[@johnjennings487]

Thank you. This was one video just trying to show people the similarities and why they shouldn't always overthink it.

[@alfonsobenitez8574]

@@johnjennings487 Is great. It took me a while to see and understand how relays function. I spend many hours refreshing my mind. Nothing wrong with that. The problem with some peop is that they either are embarrassed to ask a question or they think they know it all. When I was in HVAC school, i asked lots of questions, some guys laughed at me, at the end I got excellent grades, I was the only one arm student there, I only have my right arm.

[@johnjennings487]

One arm don't mean your brain can't work! That's good stuff.

[@richardhaen]

John, very good video, I learned something new. Just got a question for u. On my ac unit (outside only) it has 2 capacitors 1 for fan 1 for herm, now my fan capacitor went bad so I replaced if, the herm is old I have had this unit for 25 years now it’s a Lenox. Now can I replace both capacitors with one that has 3 contacts I know the uf of both get capacitor can I get one with c/fan/herm to replace it with.? Thanks Richard

[@johnjennings487]

Yes. If you know the capacitance (uf) of each one then you can get a dual capacitor that has both on it. The only thing I can forsee that looks different is that you would possibly have 1 extra wire left over and could be removed. Since each capacitor needs power coming into it you would have a wire for each coming from the contactor (generically speaking) but if you replace with the dual capacitor you would only need 1 wire since it is just 1 capacitor. There are some amperage values to consider so I would keep and use the one that is for the compressor, remove the one currently used for the fan. The wire going into the compressor capacitor should probably be a large enough wire gauge to handle the new capacitor with both motors.

[@richardhaen]

@@johnjennings487 Thank u very much, I thought that it could be done but wanted to make sure. I will but a Saul capacitor and have it ready if or when mine goes out. Sure do thank u for ur quick reply and knowledge. Again thanks Richard

[@brandonchandler2838]

John I have a new Goodman that looks just like that set up with a 15 kw heat strip and ac but I need to add my 2nd thermostat to it to control my hardy wood furnace. Can you explain to me how to do that. I’m really a visual learner lol

[@johnjennings487]

Hardy wood furnace...so it is one of those that are completely outdoors and you are just circulating water from it into a water coil in your ductwork?

[@WhiteWakedNProud]

Can the board in the condenser be swapped out in the same manner, but also add a thermal relay for the crankcase heater? The board needs to be programmed by a dongle and is meant to be communicating with another system. Since it's a donor from am old job, and for educational purposes I want to get going. I also have to add a contactor for the compressor. Possibly one for the fan motor as well I'm not sure if the relays in your video can handle the outdoor units fan amperage

[@johnjennings487]

Possible but it isn't as smooth operating without a timing feature. Probably end up with more parts and pieces taking up space but it is possible. Have seen a crankcase heater with in inline temperature switch set at like 70 degrees...wired straight to bottom of contactor for continuous power. The 90340 relay should easily handle the fan motor on most any residential setup.

[@teklesenbetgebreamlak7365]

Thanks for your video, l have a guestion how do l know everything correct write on the fan relay any help how l make sure connect write Thanks again

[@johnjennings487]

Thanks for commenting...this can be a tough one depending on what you are wiring since I can't see it! I will just use the 90340 relay for reference. Put main power (L1) going into the switch, on terminal 3, then put a wire from terminal 1 going to the actual load (light bulb for example). The load should also have another wire that returns to a Neutral or L2 to complete the circuit. I hope this helps some but it just might be too vague of a question and answer. If all else fails, I have done it another way though. It is this...wire it up how you THINK it should be and turn the power on. Electricity will always correct you if you are wrong! Thanks again.

[@BestHVAC]

Thanks John, That is a really good explanation. However, my mind can not quite follow the electric path. I will have to draw it out. I am not sure why the call for fan would be used to energize the relay. I need to see if I can wrap my head around this with some diagrams. But overall, a very good video.

[@johnjennings487]

I always have to draw it out! An old teacher of mine said that once you draw it and can make it work on paper...the hard part is over. Thanks for watching.

[@1971omi]

Hello. Did you possibly have time put a video together of sequence of operations of heat pump just with relays how it was used to be all mechanical. Please. Thank you so much

[@johnjennings487]

It might be a few weeks but I do plan on doing a sequence of operation type video for a heat pump.

[@tenncutt]

Got a furnace with no control/circuit board that blew a transformer (no fuse) replaced transformer and added fuse and blows the fuse instantly when i turn the power on! Any thoughts?

[@johnjennings487]

Textbook "short" in my mind. It could be something in a thermostat or just a rub between two wires or a wire and the cabinet. If it blows the fuse as soon as power comes on (not on a call for hear or cool from the thermostat) then I would be doing a continuity check on my thermostat wiring to find the issue. Something between "r" and "c" ain't right! I have seen it plenty of times where exposed wiring outside can weather and the insulation falls off leaving exposed touching wires but I am not sure if that is your case here. The continuity function of a meter should be enough to find the short..

[@brandoncorrea511]

Hey I have question on the 2 reds on the fuse. One is connecting from 24v transformer and where’s the other one coming from? Pls help

[@johnjennings487]

From that going into the red thermostat wire (usually wire nut together) the will eventually go into the thermostat R terminal.

[@hernancastillo2249]

Your videos are very good.. I have a question, my air does not heat.. It just blows cold air.. I already changed the thermostat, the capacitor, and nothing..?

[@johnjennings487]

Thank you. Do you know what type of unit you have...a heat pump system with electric heat or a system that is electric heat/gas heat with an air conditioner?? It is hard to say without knowing what should be running. It could be any number of things.

[@hernancastillo2249]

@@johnjennings487 It's electric, not gas.

[@johnjennings487]

I am assuming it is a heat pump since you mentioned replacing the capacitor. And I am thinking that it isn't running at all. Start simple and make sure breakers are on and power is going into the contactor of the unit. If so, check for 24v on the 'Y' and 'C' of the low voltage wiring entering the unit. If it is going into the unit (usually has wire nuts connecting to the factory wiring) then it should end up at the contactor coil (usually the sides of a contactor). If it is at the wire nuts and not at the contactor coil then you have to find out of it is something like refrigerant pressure switch or a board issue. I would also check the pressures in the unit. Hopefully not a leak in the system.

[@hernancastillo2249]

@@johnjennings487 You do not have another social network or where I can communicate with you.

[@Harveje]

After 2 failed Ecm 2.3 motors and 4 yrs out of warranty along with a mad family I put in a psc and relay for the blower. 2 stage, 2 compressor split system heat pump with electric strips. My question is can I use a fan relay board and a relay to get med fan speed while in ylo and high speed when in y2 or emergency mode? Thanks

[@johnjennings487]

Short answer -probably - after you.hacked up all the wiring. It would take some thinking to get it exactly wired perfect but i am sure it could be done ...BUT...i would just say that if something ever happened in the relays and those two speeds were powered at the same time it could catch on fire. The only times i personally have heard of or seen a motor on fire was because 2 speeds were energized at one time. I think that is why a lot of PSC model air handlers energize just a single speed no matter what mode it is in. It is just easier and no risk of fire!

[@Harveje]

@@johnjennings487 John, thanks for the reply and info. I’ve got to do allot more research and data gathered but I was thinking of using the fan relay board activated by G call hvac line out to relay and nc with med speed tap. Use y2 and c to trigger the relay and put high speed tap on no terminal I just can afford any more 2.3’s and their not so good history. Thought about the quick boards but they’re not cheap either. Thanks again

[@johnjennings487]

My co-worker had the same problem and finally just put in a PSC motor. No problems since then! But he didn't have a 2 stage cooling unit. You can do it but just have to work the wiring out right.

[@armdelgado]

what does the brown wire(heat strip) does/function on the relay?

[@johnjennings487]

If I remember the goodman heater kit wiring correctly, i think it is used for a 2nd sequencer or relay providing a second stage of heat strips, because they use a blue for the 24v common. If it is another brand besides that I would have to know the model in order to look up the wiring diagram

[@user-ru6jz9bu4i]

I may have missed it but do you loose and functionality with the relay?

[@johnjennings487]

All the circuit boards have relays on them. Little smaller looking and probably use DC voltage but still a relay. So I try to keep it simple in my head and one thing I tell myself is this - relays react instantaneously but circuit boards can be programmed for different timings to bring stuff on or turn it off.

[@solitarioelloboferoz947]

Thx good information.. be pro

[@johnjennings487]

Thanks

[@dobietoms1463]

Good Job God Bless

[@johnjennings487]

Thanks.

[@PBS-nm1uu]

please do one on sequence of operation, thanks.

[@johnjennings487]

I plan to get one of those out soon.

[@mohh4252]

Thank u for the video My heater is runing non stop it passes the temperature been set for, I changed the thermostat and filter and it keeps running, it was working fine couple days ago Thank you

[@johnjennings487]

If it an electric furnace type then it might have something to so with the heat sequencer/heat relay switch being stuck closed. (Plenty of people have had that issue!) If it is a gas furnace then it will likely get a little more complicated/expensive... which type of system do you have?

[@mohh4252]

Thank you it's a goodman air handler electric, I was thinking maybe the control board but I will try to replace the sequencer

[@mohh4252]

Change sequencer it works now thanks for the tips

[@johnjennings487]

Don't thank me...you did all the work!

[@alfonsobenitez8574]

What was the information on that relay as amperage?

[@johnjennings487]

Forgot exactly but I think it is something like 12 amps @ 125v.

[@jmc6940]

would a programmable solid state relay also work?

[@johnjennings487]

I can't think of why not.

[@ranimouf]

Hi, I have another question. I have a control borad that doesn't have a fuse. It has 6 wires connected to it. It has the 24v red wire, The common 24v and the green wire all connected to the board. I m wondering why the 24v red wire also connected to the control board since it already has the 24vcommon and the green wire connected to it. The other 3 wires are the speed wire, the 240 v wire and the wire comming from the heat strip. My question why do they have the 24v red wire also connected to the control board? Sorry I can't send you a picture but The control board part # is WJ26X24063. it has 3 terminals in the back red, then blue then green all connected. I m just trying to figure out how to replace it with a 90340 relay. Thank you for your help

[@johnjennings487]

For me (personally) i think like this...1...a circuit board needs power to its brain in order to watch what's going on...2...circuit board give better option than a relay. Relay is instant on and instant off but circuit board have a program to, for example, give us a fan delay timing when turning off. So short answer is your board need the 24v red to work right! I would guess it has a 30 seconds delay (or something similar) before it cuts off...even after it loses the 24v on the green. To replace it with a relay would be using everything but the 24v red. The relay coil would need 24v on green and 24v common to the 24v coil of the 90340. High voltage would hook up in proper place on switching part. But you lose all "timings" with a plain ol' relay. ***I hope I got close!

[@ranimouf]

@@johnjennings487 thank you for your detailed explanation. I have few of these control boards running but for some reason some of them keep failing and need to be replaced. I have one that was replaced with a relay by an ac guy long time ago and that one is running good. I m just getting fed up with calls from tenants about the same issue. Also these control boards are getting very expensive to replace. Thanks again. Onetime, we lost power in the complex and when power came back two ac units wouldn't start because of these control boards failing to work.

[@bamatractor]

I was considering adding a relay that energized off the 120 terminal feeding the fan. Trying to take the load off the board relay with a secondary relay. Seem like these board contactors have a lot of failures.

[@johnjennings487]

Circuit boards are nice and quiet compared to some relays. That ol' 93-340 is tough to beat but it does 'click' and make some noise.

[@CreativeWerxGFX]

That's awesome dude! ❤Of course any thermal limit switches are not active, right? Sweet quick fix though, better than freezing to death!

[@johnjennings487]

Definitely better than freezing to death. Not sure about the limit switch part you mentioned...guess it depends on exactly what you are doing. Thanks for commenting.

[@CreativeWerxGFX]

@@johnjennings487 Actually after watching some more vid's I think that the low/high pressure switches and the thermal discharge switch are all connected in series outside where the condenser is, so even without the air handler board they should still function. This begs the question, why have a circuit board? The only thing I can think of is the 90 second heat delay! But that's not 100% needed since it just blows left over heat and cold left in the ducts after the unit shuts off.

[@johnjennings487]

If it is an air to air heat pump then it is probably a simple time/temp defrost board.

[@vidard9863]

If I understand you, that's all built into the heat kit and he didn't touch that part.... But I think that is the purple wire he put in the normally closed. When the heat kit is energized that should send power to the fan.

[@johnjennings487]

Yes, purple wire from heat sequencer goes brings power back to the NC switch on the fan relay in order to power the fan when the heat strip(s) is ON.

[@GotchaplumberGotchahvac]

? When you add one leg of power to one side of high voltage side of 90340, how are you getting 208v to energize fan motor? Assuming you are pulling from one leg of power; e.g., 240v & use half, then 120v would be present. How are you attains the full voltage, say 208v?

[@johnjennings487]

You are right. I am only breaking one side of power so it is just 120 v on "L1" going in and out of the relay. I have a 208 power source in the shop i do most videos in and the guys i was talking to were having problems understanding that one legn of 208 is 120. They thought is would be exactly half since it is one side of power. So occasionally i do say it "not right" (and of course it is on a video) but am trying to play off of what they know for now.

[@johnjennings487]

I swear it ain't on purpose!! But somedays I hate thinking about editing and redoing a video segment. For me it is hard to do everything in one smooth take so i just go with it knowing i'd rather be fishing. I'll try to be better from now on!

[@CreativeWerxGFX]

Isn't the purple circuit normal open? If it were normally closed would the heat strip be running all the time?

[@johnjennings487]

The purple wire does come off of the load side of the heat sequencer and goes to the normally open switch on the fan relay. If you did the N.C. then yep...heat strip is on when the fan comes on!

[@user-mr8uv6ue4h]

Hi For the Goodman circuit board where you have NC,NO and COM. The way it work, you can only use it for one speed? How do I pass my 240 through it? If yes, do I need an additional component for my high speed for cooling? Thx

[@johnjennings487]

It is a "one speed at a time" control board. It was set up that way and you shiuldn't need to do anything else. The speed you want to use goes on the COM terminal. The purple wire from the heater kit goes to the NC, and red wire from L1/primary side of the transformer goes to NO. No more no less!

[@user-mr8uv6ue4h]

⁠@@johnjennings487thank you for taking the time to respond. So if place my slow speed on the com terminal, one hot leg on the NO terminal and energized my relay my blower kicks on. What the point of having hot wire from the primary on NC terminal? What is it use for?

[@johnjennings487]

It is just a backup/fail safe for running the blower motor when the heat strip(s) come on...have to have airflow!

[@user-mr8uv6ue4h]

@@johnjennings487 thank you. Last question. Can you give me an example of a component I can use to turn my cool ( fast speed) on? I’m currently an hvac student and the school does a horrible job of teaching

[@johnjennings487]

Sure the goodman board is pretty much just a relay that has a connected set of 2 switches. 1 normally open and 1 normally closed. If you want to "cadillac" this thing a run a low speed for heat and a high speed for cool...no problem! You need a relay with 1 normally open and 1 normally closed switch! Just on this one you have to have them separated...no COM terminal. The COM terminal just means that the two switches share that point and for a PSC motor...that is usually where the fan sped is connected. Oh, and make sure if you go with the "new" relay that you program the thermostat to let the equipment turn on the heat. That way you will use the normally closed switch in heat mode as intended.

[@advancedbmg]

So I run into this all the time they might have a ECM motor or they just have a old unit and the board goes out and they really don’t have the money to buy a new board but my question is how can I hook up the heat and the cool For the fan and make it cut on and off properly even if the fan goes out and the heats on where it was shut off using the relay if that makes sense to you I don’t understand how to use a relay with heat and Cool off the green wire Because if I hook the white wire and the heat strip just comes on when it calls for heat. What if the fan goes out? How can I make a safety using relays

[@johnjennings487]

If I am following your thoughts correctly...here is how I would use then90-340 relay. Terminal 1 (COM) = Fan speed, Terminal 2 ( NC) = L1 from heat strup circuit, Terminal 3 (NC) = L1 from terminal block/power source. You would need to place a wire from the leaving side of the heat sequencer (on the high voltage wire that is going to the heat strip) to the Normally Closed switch/terminal on the fan relay. If it is the 90-340 relay the wire would go on terminal 2, terminal 1 would be the fan speed wire. This would be a high voltage circuit to power the fan at the exact time the heat strip is powered. No need for 24v on 'G'. Cool mode, the tstat would power 'G' and close the switch from 3 to 1 on the relay and power the fan.

[@realSamAndrew]

What's the purple wire for and is it always energized?

[@johnjennings487]

The purple wire is "coming from" the heat relay/sequencer/contactor and is energized when the electric heat strip is turned on. It goes into the normally closed switch on the blower board and ensures the indoor fan is on when the heat strip is on.

[@realSamAndrew]

@@johnjennings487 I see. What controls when the heat strips come on? Does that have its own separate board?

[@johnjennings487]

For the simple Goodman unit that we are talking about, and a lot more out there for that matter, the heat sequencer is not controlled by a circuit board per say. It is usually wired to the white wire coming from the thermostat. Just a wire nut connecting the white thermostat wire to the white factory wire going to the sequencer.

[@kennybakerhvacr5751]

I think I'm missing something. The way I'm understanding it is if we put the purple heat strip wire on the normally closed point won't it shut off when we bring the blower on? I know this isn't permanent but still just making sure I get it

[@johnjennings487]

Just so I say it right let me start with this...2 separate circuits, one for the heat strips one for the blower. The purple wire connects the heat strip circuit to the blower. This is a redundant safety circuit because "back in the day" the tstat turned the blower on in cool mode but the system had the responsibility in heat mode. (Think old fan limit switches in furnaces) The purple wire here feeds the high voltage heat strip circuit L1 power into the NC blower relay switch so that if the heat strip is on then the blower is on. Whether on a fan board or just a 90340 relay the switches and function are the same.

[@johnjennings487]

If we are in cool mode then the NC switch on the blower relay/board should open and the NO switch will close to bring on the blower. By the NC switch opening in cool mode, the purple wire doesn't let any power into the heat strips circuit. The design is supposed to be this way...the purple wire feeds power FROM the heat strip circuit INTO the normally closed switch on the blower relay. My brother in law had a bad fan board and the normaly closed switch was stuck closed all the time. This made the purple wire circuit flow backwards! It fed L1 power from the fan board NC to the heat strip circuit. So anytime his fan came on in cool mode his heat strips were on. It was back feeding through the stuck NC switch and that was too many amps for that fan board. Hope this helps.

[@kennybakerhvacr5751]

@@johnjennings487 thank you for both replies. I do get it now. Sorry I needed the drawn out version lol

[@ranimouf]

I want to understand why you put the heat strip purple wire on the closed circuit. How does the relay turn on the blower and the heat strip at the same time? Thanks

[@johnjennings487]

Nothing more than a parallel circuit...but you have to understand that it all originates from the heat strip high voltage circuit. Hugh voltage power on L1 comes into the heat relay/sequencer switch. This switch will turn the heat strips on and off AND also the blower. (at least this is the thought process to understand). When the heat relay switches closes it sends power out to the heat strip AND to the Normally Closed switch on the fan relay. Power just goes right through the fan relay since it is a closed switch...that turns on the fan! Everything hinges on the heat relay switch. Of course when the switch on the heat relay opens, it turns them both off. Hope this helps.

[@ranimouf]

@@johnjennings487 Thank you for the info

[@ranimouf]

That purple wire that you connected it in the the closed circuit of the relay. You said before that it was a heat strip wire. Is that correct? Thank you

[@johnjennings487]

Not the heat strip wire but it is the wire that attaches to the same terminal that the heat strip is connected to on the heat sequencer. This purple wire is bringing power from that heater circuit into the NC terminal of the fan relay.

[@alfredhines505]

I am asking you to do a video, of how to convert a X-13 Motor or a multi speed motor to to P.S.C motor. I want to get the full understanding using a 9340 relay. Thank u Sir, for the knowledge i really appreciate it.

[@johnjennings487]

I think I could do that one. Let me see what units I can put my hands on in the shop. Thanks.

[@ranimouf]

How about the heat strip? how do your wire it in the relay?

[@johnjennings487]

If you talking about powering the fan motor when the heat strip comes on then you have to connect the wire from the outlet of the heat relay to the normally closed terminal on the fan relay.

[@ranimouf]

@@johnjennings487 then, how can you get the fan motor to come on in both cooling and heating if you connect the heat strip in the normally closed terminal of the relay. I think you could have explained how to wire the relay by connecting all wires including the heat. Do you connect the heat strip to the relay too?

[@johnjennings487]

This is just a relay for the fan, the heat strip has its own relay. For the fan relay I remember it this way...the N.O. terminal is L1 power coming in from the main terminal block to power the fan. The N.C. terminal is L1 coming from the heat strip circuit to power the fan when the heat strip is on. The COM terminal is power leaving the fan relay to go to the motor.

[@pipi7731]

I see your point on replacing with OEM. But, the price difference in X-13 and PSC is significant enough to try this relay without the board as a permanent fix. Is there another way to make this conversion?

[@pipi7731]

It would help to trace the transformer wires to make sure everything is connected.

[@pipi7731]

How does the heat strip plug in to the relay?

[@johnjennings487]

I would say that the easiest way is to use the QwikSwap X1. It basically is a plug for plug solution but it does cost a few dollars If you already have the PSC motor and relay, you won't actually run the heat strip through this relay. It has its own already. What you can do is have a 'redundant circuit' coming from the heat relay into the Normally Closed contact of this new fan relay. On Goodman units it is a purple wire already there. If you want you could also program your thermostat to control the fan. There is most likely an option for "fan control" amd you get a choice of either "system" or "thermostat". Choose thermostat, this way on a call for heat or cool it should always energize the 'G' for the fan circuit.

[@juliangonzalez3541]

can you do that in any other brand aswell

[@johnjennings487]

Sure. I have seen quite a few simple fan boards that you could do this on. Goodman, Rheem / Ruud, etc. I would do this as a temporary "fix" until I got the OEM replacement board but it could be a more permanent replacement if you wanted.

[@renecuevas4128]

Tnk u. I m replacing a Time delay board today but i could put a relay the day before and give Cooling to the customer i guess. God bless u my bro....tnks again

[@johnjennings487]

People like to be treat well and that could be a way to have a customer for life!

[@philochristos]

That's all my air conditioner has--a relay--but it's a time delay relay that uses heat to close. I need to find a replacement for it. Maybe I can replace it with a board. :-)

[@johnjennings487]

I don't see why not. That's why i put the two arrows on my thumbnail...it goes either way!

[@TheodoreMeche]

What if i take wall thermostat out and heat elements turn on and off the only way to turn it off is kill breaker

[@johnjennings487]

Sounds like a bad heat relay or sequencer...depending on what you have in the unit. If it turns on and off with the thermostat out of play. It seems to be a switch stuck closed on the relay.

[@WhiteWakedNProud]

gonnna do this to a 5k armana unit donated to me, that was to smart for its own good, so ima give it mercury and a relay

[@bodyjewels]

Where are you located.. i am in fla. I have a goodman outside ac unit. The heat relay blu.. i am getting insane quotes for 600 bucks. Help.

[@johnjennings487]

Everything is expensive now, even here in the Carolinas. Seems like more products are harder to find and the cost has gone up all across the board. Is it that much for just a heat relay?

[@bodyjewels]

@@johnjennings487 no the total part is about $142 that's what the k19 kit and the heat relay but everybody wants to rip me off for installation which takes him about 1 hour

[@bodyjewels]

I've been watching your videos like crazy I'm turning into an expert with my house at 65 LOL I'm about ready to buy the parts and try to do it myself

[@johnjennings487]

Well I appreciate you watching the videos. I know there are a ton of guys/gals/companies freak out when a homeowner tries doing their own work or when someone encourages them...but who doesn't use KZbin?? Nobody! We all look for stuff trying to learn. There are a lot of things that are fairly easy to handle as far as using you hands but the average homeowner doesn't have the test equipment and experience for troubleshooting. I am not going to go into any "disclaimers" but just be careful. If you think you can fix your unit and can buy the parts, well...

[@kizito8888]

Your channel has great tutorials. A white beard comes with wisdom.

[@johnjennings487]

Thanks. I am still holding on to a few dark strands so I am not fully there yet!

[@kizito8888]

@@johnjennings487 Well, we will watch you grow out those few strands along the way. Keep the informative videos coming. God bless.

[@milo6373]

Speed black wire and yellow line to contactor start up on blower for a 20 + yr old trane gas package unit ...

[@johnjennings487]

Might be a little different depending on if it has an old fan/limit switch or a circuit board! I have mostly heat pumps in my area and haven't been to an older gas-pack in a while.

[@donaldcarter4324]

So one would assume this air handler is now less efficient?

[@johnjennings487]

Depending how you look at it I guess. I try to show a few of my guys what is really on the circuit board. They think it is something magical and don't like to use a multimeter to check it out. This shows them what they already know...it is/can be a simple relay. The unit in this video was part of a 13 SEER Goodman system and it had a fan board but we have a new 14 SEER Trane system and it has a relay. Go figure.