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D.E. Anderson
D.E. Anderson, Industrial Refrigeration Service Manager
Category: HVAC
Satisfied Customers: 198
Experience:  15 years experience. Design, install, service of residential & commercial hvac/r equip.
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I have a LENNOX 410a S/N 5810B09181 OR M/N XC21-036-230-04,

Customer Question

i have a LENNOX 410a S/N 5810B09181 OR M/N XC21-036-230-04
JA: I'll do all I can to help. How long have you been dealing with this?
Customer: SORRY I WAS WAITING TO SEND THAT
JA: Do you plan on doing the work yourself?
Customer: this is harold A. yes i'm an a/c contractor with a issue with this fan motor not coming on 24v. to the motor with showing 110v. going throught the motor, but the contactor is not getting 24v. from the circuit board i think it a bad fan motor and a safety back-up soon if the gos out the copressor won't run out on over load, but i don't want to chance out the motor and find out later it a bad pressure switch and i never seen such a dirty condenser coil i did wash it down, but it
JA: What's the make and model of your machine? And can you guesstimate how old it is?
Customer: i sent that 1st. at the top
JA: Anything else we should know to help you best?
Customer: let me re read it but i think this is the problem
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the HVAC Technician about your situation and then connect you two.
Submitted: 1 year ago.
Category: HVAC
Expert:  D.E. Anderson replied 1 year ago.

Hi, let me look up a wiring diagram for that machine, or if you have it available, you can send me a picture of it. THanks

Expert:  D.E. Anderson replied 1 year ago.

If you push the contactor in, does your fan motor run? Thanks

Customer: replied 1 year ago.
no
Expert:  D.E. Anderson replied 1 year ago.

I am unable to do a live phone call. It is very loud in my home right now, I apologize

Expert:  D.E. Anderson replied 1 year ago.

Do you have any error codes present on the unit?

Customer: replied 1 year ago.
do you read what i sent to the lady to start
Expert:  D.E. Anderson replied 1 year ago.

Yes, what I see says nothing about an error code. That's why I asked.

Customer: replied 1 year ago.
did you read i sent to start i stated this
Customer: replied 1 year ago.
how do i send you a picture
Expert:  D.E. Anderson replied 1 year ago.

There should be a paperclip icon above the text box where you type. Click it and select your file

Customer: replied 1 year ago.
24v. to contactor is not working through curcuit broad to contactor think motor is out and may be a safety back-up for compressure ?
Customer: replied 1 year ago.
fan motor is out
Expert:  D.E. Anderson replied 1 year ago.
There is a high pressure safety, but there is also a procedure to do a fan test with that machine. I have found a copy of the troubleshooting and settings guide if you would like me to send you a link to it.
Customer: replied 1 year ago.
no error code that i could see i was brite out today
Customer: replied 1 year ago.
i feel if the fan motor goes out the circuit board does not send 24v. to the contactor to activate the compressure to come on i don't want to find out its a high or low pressure switch
Customer: replied 1 year ago.
the guy buy's a new condensing fan motor for install
Expert:  D.E. Anderson replied 1 year ago.

To verify the fan motor is bad, you first turn high voltage off to the condenser, then remove both brown and black wires from the j2 terminal of the fan motor control board. Make sure thermostat is in the off position with no calls heat or cool. Turn 240v back on to the condenser, then connect a 9v batter to wires you disconnected from the motor control board. Brown to positive and black to negative. Motor should run at a reduced speed. If it does not run, then replace the motor. I agree that if the fan motor does not operate, then the control would keep the contactor open, but I do not see anything yet in the service guide that verifies that. I will be more than happy to provide you a link to that service guide if you wish. Thanks.

Expert:  D.E. Anderson replied 1 year ago.

It could also be a bad motor control. That is why you should perform the motor test as well.

Customer: replied 1 year ago.
also the condenser fan coil from top to bottom was as dirty as it gets really matted and had to wash it all down also feel this could have help to over heat the fan motor, so there no way it a pressure switch it was 95' degees out and i feel the tech before me over charge it, but when i push in the contactor manual the compressor run find
Customer: replied 1 year ago.
Are you talking about the fan module on the motor
Expert:  D.E. Anderson replied 1 year ago.

Yes, the filthy coil would absolutely cause a fan motor to go bad, however, typically the head pressure switch would have shut it down if it was reaching excessive pressure due to filth. The head pressure will trip anytime the head pressure reaches around 450psig, which could easily be caused by a filthy coil not just excess charge. If he did overcharge it, then it would reach that pressure much quicker. I believe that switch is an auto reset though and if you are off now then that switch should have closed again and continued to pass control voltage unless the switch stuck open. Which would be unlikely unless it was short cycling a lot on the switch. I would think your customer would have called for service soon enough that that would not be the case

Expert:  D.E. Anderson replied 1 year ago.

I feel that you are on the right path with the fan motor, but I would do the prescribed motor test before condemning it.

Customer: replied 1 year ago.
Actually since the condenser fan motor it was no longer turning he had it off all day till I got there this afternoon and when I pushed in the contactor the compressor work fine
Expert:  D.E. Anderson replied 1 year ago.

Then that just verifies that there is nothing wrong with the compressor.

Customer: replied 1 year ago.
I was hoping you would know this off the top your head, somebody I'm sure those these units well enough I was hoping for an answer not right back to troubleshooting
Customer: replied 1 year ago.
Sorry but with this lennex this has to be a common problem
Expert:  D.E. Anderson replied 1 year ago.

Ive explained how to test the motor. That is what you need to do. I am not in front of the unit seeing exactly as you are. I don't believe your pressure switch is stuck open. I would do the motor test as lennox says to. I cannot say with great certainty that the motor is bad because you have not done the motor test as Lennox says to. I also would not be able to tell you for certain if the pressure switch is stuck open or not. You can ohm that pressure switch out with a meter and verify if it is stuck open or not based on whether or not you have continuity. If your motor isn't working, then I do not believe it will start the system but here is the troubleshooting guide. I could not find anywhere in it where it says it will or not, but an LED light on the control will tell you if the board is bad or not. There are troubleshooting procedures that Lennox prescribes in the guide and that is what we use to determine solutions and causes to the problems that occur. Most of us work on such a large variety of equipment that its nearly impossible to have a definitive answer to whether your fan motor is bad or not without doing the test that Lennox recommends

http://www.heatingandairparts.com/documents/XC21%20NEW.pdf

Customer: replied 1 year ago.
I checked out the circuit board and even looked on the back of it nothing shows to be burnt, so do you feel if the motor burned out the circuit board would not allowed 24 volts to run the compressor to the contactor
Customer: replied 1 year ago.
Remember when the cool is turned on the thermostat everything's on from the circuit board to the contactor there's no 24 volts
Expert:  D.E. Anderson replied 1 year ago.

That's correct. In these relatively modern systems, many of them have controls that recognizes when there is an issue with a component and will cease operation or prevent it in the event of a failure. I just felt that it would be important to do the motor test before ordering a motor. Also, there is a motor control board that could be at issue, but there is usually an LED light that indicates when it is bad. You also cannot rely on burned spots alone to verify a boards function. I have found countless boards in a variety of equipment from micro controlled HVAC systems such as this to ice machines and Novar systems in parallel refrigeration that showed no burn marks but were defective.

Expert:  D.E. Anderson replied 1 year ago.

Also, there would typically be a code present with a high pressure switch trip

Customer: replied 1 year ago.
it could be a circuit board a fan motor or pressure switch issue which I already knew this, can we at least narrow this down to a percentage, still do the motor check
Customer: replied 1 year ago.
I did look at the LED lights in did not see anything flashing on any of the lights
Customer: replied 1 year ago.
Do you know where the LED light indicator instructions are listed on the unit
Expert:  D.E. Anderson replied 1 year ago.

Is it wired to an icomfort thermostat?

Expert:  D.E. Anderson replied 1 year ago.

Were all the lights off or solid on?

Customer: replied 1 year ago.
No it looks like a common thermostat
Expert:  D.E. Anderson replied 1 year ago.

I was asking about the icomfort stat because it will provide additional error information which is otherwise inaccessible.

Customer: replied 1 year ago.
Okay I guess I'll have to do the fan motor check so what was your percentage I won't hold you to it and we'll call it quits
Expert:  D.E. Anderson replied 1 year ago.

Wait, were the lights solid on?

Customer: replied 1 year ago.
Actually I believe they were but I didn't see any flashing
Expert:  D.E. Anderson replied 1 year ago.

If the led lights are solid on it indicates an internal control failure. You should power cycle the 24v control power and see if it corrects it, if it returns to both led lights solid on, then the control itself is bad. If you follow that link I sent you, page 38 has all the LED codes.

Expert:  D.E. Anderson replied 1 year ago.

Correction, page 34

Customer: replied 1 year ago.
I believe the red light was the only constant on
Expert:  D.E. Anderson replied 1 year ago.

If red is on and green is off with no flashing then the low pressure switch has the unit locked out.

Customer: replied 1 year ago.
Can I run a test by cutting both of the wires running to the low pressure switch and wiring together getting these together to bypass the low pressure switch and if it comes on I know that's the problem
Customer: replied 1 year ago.
The Quick Test
Expert:  D.E. Anderson replied 1 year ago.

Yes you can

Customer: replied 1 year ago.
I believe the low pressure switch is going to be on the suction line is this correct
Expert:  D.E. Anderson replied 1 year ago.

Actually you could just jump out the terminals its wired to on the control

Expert:  D.E. Anderson replied 1 year ago.

Yes low pressure would be on the suction line.

Customer: replied 1 year ago.
I can actually do this on the terminal block with all the pressure switches correct
Expert:  D.E. Anderson replied 1 year ago.

Yes with the low and the high, according to the wiring diagram

Customer: replied 1 year ago.
The only thing I'm thinking that's the compressor was running when I pushed in the contactor this kinda send me back to a bad motor or the modem on the motor I believe
Customer: replied 1 year ago.
Don't mean to be running in circles
Customer: replied 1 year ago.
Okay where will I get this manual sent to me
Expert:  D.E. Anderson replied 1 year ago.

Why does that discourage you from the pressure switches? The compressor would run regardless when you press the contactor in no matter what the pressure switch status is. The pressure switch only breaks control voltage, so when you press the contactor in, you are sending 240 to the compressor. I would be concerned if it didn't pump when I did that.

Expert:  D.E. Anderson replied 1 year ago.

That link is the guide.

Customer: replied 1 year ago.
the unit was off when I got there and cold so I guess there's no reason for the pressure switch to cut it out
Customer: replied 1 year ago.
Okay thank you
Expert:  D.E. Anderson replied 1 year ago.

Well, if it has lost excessive charge or frozen up, then the low pressure switch would shut it down.

Customer: replied 1 year ago.
That's what I thought and it hasn't done that I checked it when the compressor was off it shows to have a lot of freon
Expert:  D.E. Anderson replied 1 year ago.

How many PSIG?

Customer: replied 1 year ago.
I believe with the compressor off it was somewhere around 220 to 250 PSI
Customer: replied 1 year ago.
410A of course
Expert:  D.E. Anderson replied 1 year ago.

Its enough the pressure switch shouldn't be open

Customer: replied 1 year ago.
I didn't get your last text
Expert:  D.E. Anderson replied 1 year ago.

That is enough pressure that none of the pressure switches should be open, but that's not to say they aren't bad. I would also powercycle the control after I verified the switch status

Expert:  D.E. Anderson replied 1 year ago.

If you know for certain the switches are closed, yet you are still getting a low pressure lockout error, then I would replace the control.

Customer: replied 1 year ago.
Okay so what's your percentage thoughts I won't hold you to anything
Expert:  D.E. Anderson replied 1 year ago.

Always powercycle the control voltage after verifying the switch status because a lockout is just that a lockout, so it will not necessarily turn back on immediately after the switch has closed. Also, check the pressures during operation if you get it to run, because you could also have a metering issue or dirty indoor coil or restricted airflow for some reason or another

Customer: replied 1 year ago.
I'm not sure I understand the Pro Cycle control test
Expert:  D.E. Anderson replied 1 year ago.

You mean my pressure thoughts? And power cycle the control, I mean basically to just disconnect 24v from it then reapply, that will reset any present lockouts that are there.

Customer: replied 1 year ago.
Oh okay I see what you mean
Customer: replied 1 year ago.
Can't I just turn off the thermostat and it would do the same thing
Expert:  D.E. Anderson replied 1 year ago.

No because 24v is provided to the control constantly. You can turn the breaker off to the indoor unit and back on again.

Customer: replied 1 year ago.
I believe both these units can be cut off at the main outside in turn back on
Expert:  D.E. Anderson replied 1 year ago.

The indoor is on a separate high voltage circuit and is where your control voltage originates

Customer: replied 1 year ago.
Ok so we're done unless you have anything else to add
Expert:  D.E. Anderson replied 1 year ago.

No, nothing that I can think of right off hand. If you have a smartphone, I would email that link to myself so that guide is available to you in the field

Customer: replied 1 year ago.
Yeah I believe my phone's pretty smart I have a Samsung 4
Expert:  D.E. Anderson replied 1 year ago.

lol Nice phone. I root phones. I am using an HTC one M9 right now. My dislike for the Samsung was the kernel and the OS are married so a minor programming error could be terrible, but that's a different subject lol

Customer: replied 1 year ago.
I'm assuming sending the manual to my phone maybe a problem'
Expert:  D.E. Anderson replied 1 year ago.

Oh no no lol. I was just talking about rooting a Samsung and putting a custom operating system on it is an issue. As long as you have a PDF reader on your phone it shouldbe a non issue and if you don't have a PDF reader just download the Adobe one from the google play store

Customer: replied 1 year ago.
Okay sounds good I have the PDF though
Customer: replied 1 year ago.
This job's going to turn into a learning experience before I get done I'm sure
Expert:  D.E. Anderson replied 1 year ago.

Alright, let me know if you need anymore help

Customer: replied 1 year ago.
Okay I'll let you know all this advice paid off the homeowners already asked me how much for the fan motor What's the total I'm going to have to duck this one for a short while, I know he just wants everything cool I think it's his wife starting to get on his nerves
Expert:  D.E. Anderson replied 1 year ago.

I understand. I have one of those wife things. lol

Customer: replied 1 year ago.
okay thank you got to go
Expert:  D.E. Anderson replied 1 year ago.

Thanks

Customer: replied 1 year ago.
Okay bye
Customer: replied 1 year ago.
have a good afternoon
Expert:  D.E. Anderson replied 1 year ago.

You too. Thanks.

Expert:  D.E. Anderson replied 1 year ago.

Hi, I was curious if you made any progress with your customer and what you may have found after our discussion, thanks.

Customer: replied 1 year ago.
I meant to ask you what this was costing me
Expert:  D.E. Anderson replied 1 year ago.

They should have told you a price when you made your deposit. I do not see what you pay. I only see what the payout is for me answering the question.