HVAC ohming control transformers and contactors

[MrAndrew43]

LOL, it's good to know im not the only one who salvages parts.

[DrZarkloff]

@MrAndrew43 I work for the school board so it saves money to salvage parts.

[MrAndrew43]

@DrZarkloff LOL, yeah, I hear ya bud. I keep some stuff for those cold or hot nights when everything is closed and you just gotta get it up and running. I dont like using used parts at all, but ya do what you gotta do. I enjoy your vidios by the way. Ive logged going on 24 years now and im learning all the time.

[ADUBOIS11]

what if your common wire is also the other side of the power to the air handler ? My airhandler is set up like this. One black wire 110v and one common wire 110v and one ground wire. Do I still hook up the common to the white terminal block having 110v?

[DrZarkloff]

@ADUBOIS11 I'd have to see your system to make a decision on that one.

[MrAndrew43]

@ADUBOIS11 If I understand, you have either a 240 volt, or a 115 volt transfomer. Just remember your common if it's a 230 volt is just gonna be one side of the 115 you have comming in. It doesnt matter as long as you have 230 to the trans. Now, if there are other wires comming off the same place you have to keep everything in line. If you have a 115 transformer, your common will go to a ground, and you will have your 115 volt going to a 115 volt power suply. I hope I didnt confuse you more. lol

[demented12]

Do you have the schematics for this transformer installation?

Normally they come with only 4 wires,but I haven't been able to set up this one that has 6 wires an different colors.

[DrZarkloff]

@demented12 The schematics should be printed on the transformer. A 6 wire transformer isn't all that difficult to set up after you see it done once. Two of the wires are going to be for the 24 volts. The other four wires are a multi-volt tap. You'll have one common wire. The other three wires are marked for 120V, 240V and the last wire is going to be for 208V or 460V.

[demented12]

@DrZarkloff ,Thank you for the quick response,after a while we figured out,have a nice day and thank you again.

[MrGurudude5]

can i test my hvac unit with a multimeter? and if so can you tell me how!

[BigDaddydigsdp]

Good knowledge like alway's Dr. Z

[DrZarkloff]

@BigDaddydigsdp Thanks for watching.

[bearmanly53]

do you have to disconnect terminals to check ohms?

[DrZarkloff]

@bearmanly53 It's best to disconnect them.

[fshybyte]

i have the same multimeter Field Piece and im a student just learning how to use this thing, I just found your videos on youtube and They are Great they have already helped me to understand a few things better. Keep it up!!!!

[DrZarkloff]

@fshybyte Thanks for watching.

[fshybyte]

I like your videos. I'm currently in HVAC school. I like the way you explain things, better than the instructor i now have a IOT.

[DrZarkloff]

@fshybyte Thanks for the great compliment. 

[MrAmerico1982]

thanks bud, great explanation and it really helps.

[jorgearenteria]

Great videos !!!

[sasasa1600]

Dr Z how do you test a transformer when it is still connected to the power ?

do you probe on prim side com to say 120 should = 120 ans on 24v probthe two wires should = 24v is this correct becaue i would think the 24v 2 wires are the same so you can be fooled

[DLoyKnowles]

Video is good, however you said that .020 is more resistance than .050; not true. The closer you get to .000, the less resistance there. The larger the number of ohms, the greater the resistance. 1.000 is 0ne ohm; 1000ohms is one thousand times greater than 1ohm. .050ohms is a fractional part of 1ohm. .020 is a smaller fractional part therefore is less than .050ohms.

[DrZarkloff]

@DLoyKnowles I'm sorry if I said that.

[melun1]

@DLoyKnowles voltages proporational increase with resistance

[trapshootor687]

This is a good video my class at school they talk about things like 24volts at the controlls and 120 going into the furrence but they never show were to test for power. They just go over book work and we take a quiz every day and play with light bulbs and hook them up to like 9 volt battery stupid. Thanks for the video and showing everybody.

[DrZarkloff]

@trapshootor687 Thanks for watching. Believe it or not there is a good reason why you're doing that stuff in class.

[quangfjs]

Hi Sir, i want to replace the transformer for my central air conditioner, model Trane XE900. I opened all the cover of the air conditioner but could not find where the transformer is. I saw the Contactor but could not find the Transformer. Sir, could you tell me where it could be. Thank a lot for all your vid on Youtube

[DrZarkloff]

@quangfjs The control transformer is probably in the indoor air handler or furnace.

[JUCARL23]

you should run a online hvac schooling,. your vids are very clrear and straight to the money

[DrZarkloff]

@JUCARL23 Thanks for the compliment.

[km57mex]

drZarloff tht wasnt rojasorbit question,, on the METER what/where do you place the needle or measuring OHMS, VAC , DC? i like to know that also nvermind you said ohming them, that would be the omega symbol correct?

[DrZarkloff]

@km57mex Yes.

[km57mex]

drZarloff tht wasnt rojasorbit question,, on the METER what/where do you place the needle or measuring OHMS, VAC , DC? i like to know that also

[rojasorbit]

can you please tell me where do you place the needle in meter at the beginning, when you check the coil therminals, i

[DrZarkloff]

@rojasorbit One probe should go on one wire that the other probe should go to another wire.

[domyaska]

thanks a lot !!

[quantumsignature]

You help alot of people with your very informative videos, THANK YOU!

[DrZarkloff]

@quantumsignature Thanks for watching.

[pulgaringuitar]

Your videos teach a lot. I been working in maintenance for 10 years . By looking at your videos I have learn a lot and also I compare the hv/ac equipment on my work site and they are almost the same. Your videos help me a lot, and I am going register my self in tecn. school in NY. thanks.

[DrZarkloff]

Very cool. Keep up the interest.

[steburton]

Salvaging parts?

[DrZarkloff]

I always cannibalise from condemned systems.

[domyaska]

thanks a lot !!!!!!!!!!!!!!!!!!!!!

[CuyahogaJoe]

Doc...a coat in the sunshine state?

[DrZarkloff]

lol. It can get cool in the Winter.

[CuyahogaJoe]

Better see some steam plant operation videos...lol

[got333]

So if my primary contacts don't get a reading on my transformer does that mean it's bad? I checked the secondary and they do get a reading. So I don't understand how the primary don't get any readings but the secondary does. Do I need and new transformer ??

[DrZarkloff]

I think that it's really weird that you don't get a reading at the primary side. You might want to check your meter.

[khonglap]

Very good video, Thanks for your time helping a lot of people. Good jobs.

[DrZarkloff]

Thanks for watching.

[Darvin1964]

Hello Dr Z. So when checking the leads on Tran's. If it's bad your meater will read OL Rite.Thanks

[DrZarkloff]

Yes, Open Line means the wire is bad.

[rolando7120]

hey DR Z, when you get time can you give us an intro to economizers and frequency drives... I would really appreciate it!

[zuna316]

would dirty oil in a compressor damage the windings the original grounded out the replacement was changed without a suction dryer filter oil was burnt

[DrZarkloff]

The dirty oil could damage the new compressor. Acid will destroy the motor windings.

[zuna316]

my boss taught me to charge units using the 20 degrees split i was curious how accurate is this?also the head pressure should be @ 200 and back pressure @ 40 degrees below return temp can this system be used?

[DrZarkloff]

I'm not too sure about what you mean by back pressure. I'd stick with superheat and subcooling methods.

[zuna316]

Dr Z. thank you very much for the input it is greatly appreciated.

[DrZarkloff]

Thanks for watching.

[jsemelgar]

Dr. Z. thank you very much for your hard work and time to teach us. I have learned a lot and appreciate your contribution to society. Your efforts are well appreciated by many. I bought a Fieldpiece HS36 and have saved hundreds in repairs. Thank you from the bottom of my heart.

Jim M.

[DrZarkloff]

Thank you very much for watching. I'm glad that you've learned a lot from them.

[DrZarkloff]

Thank you very much for watching.

[buckners1]

That had to be hard to do with only 2 hands!

[DrZarkloff]

It can be real difficult but then after I see the replay it all seems worth it.

[Brany666]

fluke and fieldpiece are both good meters I've seen that in electrical supply houses the only sell use fluxe. when i go to an A/C supply house they only sell field piece why i dont now i to own a fluke and a fieldpiece meter and they do the same thing and i am an electrical master and a/c master with licensees in the state of Florida/ miami keep them cumming DR Z nice vid

[DrZarkloff]

Thanks for watching. I think that Fieldpiece has been specializing their product line for the HVAC industry and Fluke's product line is for electricians.

[bervotten]

How can I check the centrifugal switch of a 240 volt inducer draft motor of a CARRIER package unit. To make sure that either the draft motor or the control board is bad.

[DrZarkloff]

You could jumper the board so that the motor gets 240 volts. If the motor spins then you probably have a bad board. If the motor doesn't spin then you probably have a bad motor.

[reereereesky]

can you show an actual connection of the 24 volt transformer with one of the wire colors being brown to the system?

[DrZarkloff]

Some manufacturers use a brown common wire.

[local614bro]

ok, ive started not leaving so many comments but ive got to after reading mr. james comment. if you want my opinion fluke is the best but thier superiority does not warrent spending $100 more dollars for the next best(fieldpiece). also fluke has failed broadin thier models to give you the options f.p. does. fluke does have a warrenty that will replace it even if you run over it with your truck. but for someone to say only hacks and poor techs would use -thier idiots_ and you asshole -for askin

[DrZarkloff]

It sounds like somebody has a bunch of Fluke multimeters to sell. I have nothing against Fluke. It's just that I've always used Fieldpiece. I like the way they feel and yes, I trust them to be accurate. Don't believe everything you read on any one web site. Check around and free your mind from other people's opinions. Try them all and see which meter works the best for you.

[JamesHuntleyy]

I belong to a Website that everybody there say that only Hacks and Tech who don't know what they are doing use Fieldpiece meters. I see you use one. I guess the most important question that I want to ask is how are they in safety? Also are they accurate and fast? I have been looking at the dual port Thermometer of theirs. I just don't want everybody thinking I am also a hack for using a Fieldpiece but the Thermometer looks good. Thanks

[DrZarkloff]

It sounds like somebody has a bunch of Fluke multimeters to sell. I have nothing against Fluke. It's just that I've always used Fieldpiece. I like the way they feel and yes, I trust them to be accurate. Don't believe everything you read on any one web site. Check around and free your mind from other people's opinions. Try them all and see which meter works the best for you.

[NedacFilms]

That is just silly... That is like a Mustang owner saying a Camaro is junk, or the other way around... I have two Fluke meters and one Fieldpiece meter that does what the three Flukes do... I've used it for over a year now, love it, and my Flukes have an 1/8 inch of dust on them...

[napais]

Can a relay be tested while you have it in your hand, with the ohmz or something else.

[DrZarkloff]

You can test the coil just like a contacto, but you won't be able to test it mechanically without energizing it.

[napais]

I asked you that, I do not know if I was the first to ask, but this it is a great video, Thanks Dr. that it is exacly what happen with me I do not know if the things that I got from the shop without a new box it is working.

[GoldRushDutch]

Well Done!

[DrZarkloff]

Thanks

[OPERATIONCINDYFUTURE]

90859v0y8wc9dimv95t3094

[DrZarkloff]

What is is all about?!

[OPERATIONCINDYFUTURE]

ve egercter

[OPERATIONCINDYFUTURE]

THANKYOU

[EETechs]

You made an error in your video by saying less resistance for higher voltage primary windings which is wrong and your meter even proved you wrong. For the 240 volts you got .067 ohms and for 208 volts you got .050 ohms.....You need to re-do this video.

[DrZarkloff]

Thank you for watching the video. I'm sorry for not explaining that you'll get more resistance on the 120 volt winding than the 208 volt and the 240 volt winding.

[hackfreehvac]

Nice to see you're still adding new videos all of the time. I've been slacking with my videos on my hvac account.

[DrZarkloff]

Thanks. It gives me something constructive to do during my lunch and breaks.

[electricianron66]

It's seems like such an easy thing to say, but as long as you have resistance from one end of the coil to the other, then your coil is good. This same rule applies to transformers and motors. If you have resistance from the coil to ground then you have a short circuit and it needs to be replaced.

[DrZarkloff]

True.

[danlapinski]

how do you know what ohms you should be reading on a partial winding to winding short as you will still have resistance in this case?

[DrZarkloff]

ohming the windings will give you an indication if the component is good enough to install. Of course, the real test is when voltage is applied.

[jimmymoss7644]

your the man!

[DrZarkloff]

Thanks

[bobbyton80]

Once again, good video Dr.

[DrZarkloff]

Thanks

[heavyhvac]

Good video DR Z I have A quiz on contactors and transformers in the am keep it coming I too would like to see something about wiring diagrams Ladder Diagrams thanx

[DrZarkloff]

It's hard to focus close on diagrams. I'll try again.

[itscool1968]

thought you would like to know i finaly cleaned my one year old fridge the other day and its amazeing how small the fan motors are in thise new units

mine is 134a what ever happend to R22.

any new becky videos yet:)

[DrZarkloff]

It's always a good idea to keep your fridge in good running order. I might be able to get Becky to help me with another video soon.

[itscool1968]

i got an idea lets get her cleaning a bard unit:)

[DrZarkloff]

Yeah right. I don't think she'd agree to that video. :)

[itscool1968]

we can try:)

[bowlingballout]

Love the technical stuff, too bad it's lost on me. :-)

[DrZarkloff]

I hope that you're learning something.

[V8Jagnut]

good vid.

[DrZarkloff]

Thanks

[FireConvoy88]

Great video

I wanted to ask if you can help us noobs on how to follow wiring diagrams, and apply it to the actual unit.

Thx

[DrZarkloff]

I'll try. It's hard to focus my camera on most diagrams.

[mechanicwarrior20]

Hmm generally when control transformers go you know right off the bat. A lot of times they just go bang...

[DrZarkloff]

It's easy to tell is a transformer is good or bad when power is applied. I was showing the viewers how to ohm the windings for problems.

[normspace]

Very informative, Jim!!

[DrZarkloff]

Thanks. It's fun, too.

[BLSzepCFH]

first

[DrZarkloff]

Yes, you are.