Tool List- www.amazon.com/shop/acservicetech Support- www.patreon.com/acservicetech For those that are looking for the tools used in the videos: (Linked Below) Here is the Link for the newer UEI DL479 Multimeter with temp sensor- amzn.to/2jtsUbJ Here is the Link for the newer UEI DL 469 Multimeter- amzn.to/2jw4ePJ Here is a link to the UEI DL389 Multimeter used in this video- amzn.to/2av8s3q Here is the link to the Fieldpiece SDMN6 Dual Pressure Testing Manometer with Pump-amzn.to/2jyK5Ka Here is a link for the Supco Magnet Jumpers amzn.to/2gS4h6z Here is the link for the Irwin Wire Stripper/Cutter/Crimper amzn.to/2dGTj2V Other tool links can be found in the video description section. ACSERVICETECH is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.
Dude I usually don’t say this but thank you, the way you explained it was far superior than any other video I found on RU-vid. Thank you for sharing you’re knowledge
Man you have saved me so many $$$. I have done my TXV, cleaned my evap, gotten my airflow straight. I have my scales, tanks, scales and portable recovery unit for my home 410a unit. I was a Rail and Bus R22 guy when I retired in 2010. By 2014 I was working on 134a in a second retirement govt fleet shop. My schraders on my own 410a unit started leaking in 2015. I am in Tampa where HVAC residential work is way overpriced and nearly every tech tries to sell units. The cheapest company in 2015 wanted $1136 to replace the valves including refrigerant which 410a was $135 for 25lbs. then. I bought my Robinaire scale, pump, recovery unit and a leak detector along with 25lbs then. I learned subcool and superheat in a day from you Chris.
So zero ohms across common and red zero, across blue .17 and across black is 24. Well figured out my problem thanks to your video. A dozen others were no where near as good. Thanks!
Thank you for this video! I was able to troubleshoot my blower fan motor and I'm not getting any ohms from common to any of my speeds or from common to one of my brown (cap) cables. No shorts though. I'm gonna have to order a new blower.
good video. Thanks. By the way, OL on the meter is not ovel limit. It actually means Open Loop. Which makes sense since your are testing for a short or open circuit. Again, good vid.
Thanks Hector, It is referred to as many different things such as open line, open loop, and over limit. They are all correct in their terminology. Over limit means that the resistance value is over the limit that the meter can read and is the terminology that I usually use, thanks
I have a 3 spd that lost medium and high spds. Replaced the cap= no change. Replaced again with 2nd new cap=no change. Bypassed switch=no change. No visible discoloration of coil. No short to ground. Should there be continuity "OL" reading between each of the speed wires? This is the one thing you dd not test for.
My blower motor hummed but never turned. When the breaker was switched off I could turn the motor by hand. I bought a new capacitor and it worked great for a few days then went back to the same symptoms. I did what you showed - removed wires from capacitor, shorted it out, and did a voltage test. Nothing. I guess I got a bad one. I read Genteq is the best so I ordered another. Should be here in two days.
Check for voltage and amperage readings on the running blower motor after the capacitor replacement. The capacitors usually don't go bad that fast but it is always possible.
Had a blower today that wasn’t turning on everything checked out good Besides I didn’t get any resistance from common to any of the speeds replaced motor and it ran fine good tips on how to trouble shoot!
I have watched others Hvac tech on RU-vid said that if using 230 volts the blower motors don’t need the common wire but this one it does have common wire . I am confusing, please help?
Ohhh i get it. The 4 connectors you are testing just loop down to the left and join up with the 2 cap wires going into the motor. I thought these were separate wires altogether.
Yeah those are the winding wires and yellow was the 120v common and the others were fro the 3 speeds. The brown and brown/white are for the capacitor, thanks
Hi: Thanks for the reply, much appreciated. On several occasions when on service calls, I've come across a unit that was tripping an RCD. But testing with a Multimeter showed no signs of leakage to ground, however when tested with the higher voltage of the Megger, definate leakage was shown. Nowadays I never go on a service call without my Megger. Andy
I tested the black and purple coming from blower to ground and the show 7 and 15 ohms what that really mean the blower still working? Because i though it supposed to read OL like you daid
GEEZ , the guy helping me at AC place their place not open today or tomorrow AND I need to ask him again something . Yes , i bought new capacitor there and installed it and didn't fix it . He said on blower motor if I disconect the cool terminal wire on circuit board and connect the bottom black wire to cool terminal that ( this is what I'm not sure what he said and needed to talk to him ) if it works ( or doesn't ) that means board is bad NOT the motor ?? OR is it the other way around ?? And yes replaced capacitor . Still the same barely running the blower not full speed and shuts down after a while with new capacitor
Great video. Unlikely you are still looking at comments on old video but just in case. What if my unit doesn't appear to have that yellow wire. Can I connect a common directly to the brown/white at the capitor?
New Honeywell RTH2410 thermostat. 4 wires. Working with Heat. Fan "On" position.....Burner comes on, and Fan operates. Fan "Auto" position........Burner comes on,,,,but Fan does not operate. After short period,,burner goes off. (Brown wire in G, Yellow wire in Y, White wire in aux/W. Red wire in R (with jumper).) Internal switch on "Gas or Oil". Honeywell said to change internal switch to "Electric". Burner and Fan come on. Both go off when temperature is reached. {temporary fix?). What can I do?
Hello Craig, First for all thanks for this great video. I understood the whole process you did but only one thing. When you said that you should not get a resistance reading between common ( yellow) and the capacitor's brown/white wire and the reason being, as you said, is that they are attached inside the motor housing. 1- Does that mean the resistance reading you are getting is the winding between common and Start? 2-and if that is the case, why can't we get a reading between common and the capacitor's brown wire? Is not the brown wire attached to the Run winding which is also attached to Common?
I think I meant that you won't get a high resistance reading but that it should be very close to 0.0 ohms of resistance since they are connected right under the motor housing. You might enjoy another video I did on the thermal overload mounted on the windings of the blower motor. Just look up "acservicetech thermal overload" thanks!
For your 2nd question > @5:24 time line the ohm reading of approx 20 ohms is between the yellow wire (run winding) and the brown wire (start winding) . that is the combined resistance going through the run wind and start winding in series
Great information. Thanks for sharing your knowledge. Does the capacitor terminals have a + or - terminal? In other words can the brown with white stripe wire (which is also connected to common) have to be connected to a certain terminal on the capacitor?
My motor is 3 speed medium stoped working, changed to high, same thing, changed to low, recently pulled out, cleanned and speed working again!! Tested the way you show on video and speed reading ok, what do you think is the problem here?? I will appreciate your feed back.
I know this is an old video, but I have a blower motor (part of an hvac system) that I asked the tech to save when the main unit went out. They just cut the wires off the motor. How do I find out what capacitor I need to get for it? I want to repurpose it for a shop dust collection. Thanks!
what one of my wires has no resistance at all with the rest of the wires (my fan black wire from my furnace has no resistance at all) its not turning at all.
Ever seen a blower run and hum/ slow down? After min runs for a bit it will slow way down so you can feel any air moving. And hum loudly. And then continue to run all day because its doing nothing. It has a run, off, and fan selector on the unit. It stays on run. If i turn it to fan, it will stop humming but stay slow. I assume xause its only running on low? Checked he speeds low is like 5.9 abd high was 2.2 i believe. Any help?
You test the resistance between yellow and brown w. White trace is 0 ohm. But the run capacitor series with start winding then parallel with run winding. I conclude that the resistance between yellow and brown w. White trace should be the resistance of the run winding, the resistance between yellow and brown should be the resistance of the start winding. What is wrong with my conclusion? and what component will be measured between yellow and brown to get 20 ohm?
Just so im not mistaking your point ....since the yellow wire and the brown/white wire are attached this would make the yellow wire the RUN winding....and by default the Black, Blue, and Red wires would be considered the COMMON point/connection???
I have a 120v blower motor. Confirmed - getting 120v coming in from the line (extension cord before connecting to the blower). Whenever I turn it on, I'm only getting 98v - motor won't spin. It worked fine a couple of weeks ago. I'm stumped. Excuse my ignorance, but, should the voltage drop to 98 once plugged in? Would this have something to do with the capacitor?
Hi master, I need some help in a blower motor that has 5 wires ( Yellow, orange, black, blue and red) and obviously the 2 wires that go to the capacitor. I don’t know which one is my common:/. Please help me.
My ac was running and I began to smell and see smoke in the house, I discovered it came from the air handler blower motor. If I switched on the power the motor would slowly turn for a minute and then stop. I purchased a new motor and cap and installed and immediately upon turning on the breaker the motor caught on fire. Could it be the relay or transformer? Also the only thing that I know that I may have done wrong is that the new motor had a white and black common wire, I only used the black because the old one only had the black.
I followed it but the only thing diferntial with the new motor was it had a black wire and white wire common...there are only three wires coming from the relay and black is there so I connected black motor to black relay. Should it have been the white?
Great video. This is by far the most helpful explanation out there. Having performed all of the checks in your video I have found no faults with my blower motor but it keeps tripping the circuit breaker when power is applied. I noticed that I get an OL when testing between high to medium or high to low or medium to low speed wires. Should this be the case? Could that be causing the short circuit? (I get the three different resistances when testing between the COM and high/med/low wires like you demonstrated.)
I have a question...and I’ll try to make a long story short, I replaced the control board today...thinking it was bad due to a wrongly labeled/tripped breaker, Anyway...after I figured out the breaker issue and the new control board was already installed...I fired up the AC, in the attic I heard the blower motor making noise...upon inspection it wasn’t starting, but trying. I tried to test the capacitor but my meter doesn’t appear to have the correct setting - so I swapped the capacitor with the working upstairs unit and the problem persist, capacitor works fine in the other unit. So I tested the blower power on the control board by pulling the black (cool) wire and the white common, put the meter where they went on the board and made sure power was on and the door switch taped - I seem to be getting 0 volts. Thermostat was set to cool/fan ON - not Auto, I’m wondering if maybe I’m doing something wrong...or if maybe it could be something else that could cause the problem cause I just installed a brand new control board and don’t see why the blower wouldn’t be getting power as there aren’t any status LED’s alerting me of a problem. I’m about to pull the blower motor out of the working unit to see if that resolves the issue...but I live in AZ and it’s pretty dang hot up there...so the less work I have to do up there the better. Also don’t want to keep throwing parts at...I’m a computer tech and mechanically inclined, so I try to do what I can before calling techs out...and I had a bad/costly experience last year with an HVAC tech...so. Thanks in advance for any advice you can offer.
If this is a psc motor and not an ecm motor then you would be getting 120v to the blower if this was a furnace and 240v if this was an air handler. You would need to make sure that you are getting 24v to the g terminal on the board which is a call for fan before testing, thanks!
Very enlightening; my a/c unit got swamped with rainwater now the interior air blower motor won't run. Two of the 3 speed windings are open; only the Hi speed winding reads 17 ohms. Could the OL heaters be the culprit since it was running on the Lo Red wire. Can I connect using the Hi Black wire?
Informative video, but wouldn't it be better using a Megger to check for grounded windings ?. The low voltage produced by a Multimeter / clamp meter often won't show leakage where a megger will.
Great Question! The multimeter is a quick service tool that would show some type of resistance if it was grounded even a little. If the reading remains O.L when you know you have good connections to the leads you are good. The megger is often something that would be used in the preventative maintenance of larger equipment. A megger is good for checking insulation level of a winding. Still would be good if someone wanted to use it. Thanks!
This video is incomplete without a wiring diagram explaining where all the wires go including that bundle of wires near the capacitor ! Can you edit video and insert this with an explanation to make it an excellent video ? Thanks Michael
Zabi ulla thanks for your comments. After I turn the power off I check to make sure that the motor is not frozen and that the bearings are not worn and wobbling or that the wheel is not rubbing up on the side of the squirrel cage. I mentioned to check that at the beginning of the video. Thanks
Amazing content, keep up the great work! Just wondering if you could whip up a series, teaching techs how to properly read and follow wiring diagrams from AC, HEAT PUMPS, FURNACE applications? much appreciated! Also, do you ever dissipate your cap using yoru multimeter set to volts? would that not be safer? Thanks again!
Thank you for letting me know what you would like to see! A 20,000 ohm resister could be used but I havent seen any damage occurring when they are the 80uf and smaller. You are really just taking the very last bit of power out since the capacitor discharged after the power shut off but the motor continued to free-spin except in the case of a start cap that has a relay to take it out, thanks
Wouldn't the capacitor self discharge through the motor winding. As you demonstrated the one capacitor lead was connected to the white wire and the other had 20 Ohms to the white wire. Pretty close to a dead short and certainly less than a 20 K Ohm resistor. I would think the only place you could expect a cap to be holding a charge would be is a high voltage DC circuit. Also, any remaining voltage would be DC and could be measured with a voltme set to DC Volts.
Thanks for the video! Very informative. I bought a used motor 4 years ago and installed it in my electric furnace. It had a capacitor with it, which I used. I noticed that the capacitor is 7.5 uF, but the label on the motor calls for a 6 uF capacitor. Anyway, this motor has been working very well for three winters now. I do have a couple of questions about capacitors though. I read somewhere or saw in a video that it's okay if the capacitor is a bit larger, but it mustn't be smaller, is this correct? Also, I'm wondering if a capacitor will give any warning signs that it's going bad or does it just suddenly fail?. Is it a good idea to buy spares or do they have a shelf life?
Here is the playlist for all the motors just pick if it is 120, 240, variable or x13, thanks- ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-x24AjKupGD4.html
They can be found in furnaces and package units too. An air handler is just a coil, blower, and low/high voltage control all in one unit. They are also called fan coil, thanks
This was a 240v 1 phase motor so there is no neutral just the one hot along with the other three hot speed taps to select a speed from and a ground. thanks
Depends on how the speeds are determined. Some motors are wired to run on one speed by using one wire and not the others. It may be as simple as switching your motor wire to a faster speed. Black is usually the fastest going thru the colors to Red which is usually the slowest speed.
Doing that with a screwdriver is not safe what so ever you just need a 20k resistor and they even sell capacitor dish chargers ....... you never know when there’s a tiny crack in your insulated screwdriver
