Hello all -

I went to turn on the heat for the first time this season (Atlanta, GA) this past Sunday and ran into a problem.

I have a Trane XR80, installed in 2005. Last summer I had my vents cleaned, and the furnace worked fine through the winter.

Now when I turn the heat on via the thermostat (move the slider to heat and push the temp arrow up) the heat doesn't come on. I hear a buzzing that lasts for about 30 seconds or so and then that stops, then repeats.

Usually I flip the heat on and after a few seconds I hear the furnace start up, or a blower starts up, and then after about 30 more seconds the heat starts blowing through the vents.

The a/c works fine, and if I just turn on the fan on the HVAC it starts up just fine.

I did some reading on the net and found the error codes. I had my wife turn it on after I closed the door on the Trane and it started flashing 3 times, and would repeat 3 flashes.

The unit itself is in my crawlspace, so it's laying to the left. 3 blinks means some sort of pressure switch problem according to the chart I read.

Could someone help me troubleshoot this? I would prefer not to have to call a tech out if I can help it.

I will show you an image of what I'm looking at, included in this post. EDIT - For some reason I can't get the jpg image to upload.

Also, I've read somewhere about disconnecting some tubes and clearing them out, but I don't see any. I'm thinking I need to take another panel off to get at those, but I'm not sure.

Halp! and thanks!!

Mike

 

Welcome to the forums!! XR80 is a trade name and there are many different models in that line. To better assist can you post the model of your furnace? It probably begins with TUD or TDD and should be located on a label or tag inside the unit where you remove the access panel.

I believe on your furnace you should have a clear hose that exits the pressure switch on the right side. Make sure this hose is clear from end to end and the fitting where the hose attaches onto the metal is clear. Also, make sure your air filter is clean.

An error code such as yours can also be caused by a restricted/blocked condensate drain, a blockage or restriction in the vent pipe such as a dead bird, leaves, bee's nest etc. So make sure all of that is clear from end to end.

The blower motor or the inducer draft motor could be the source of the buzzing. Next time you start the system see if you can isolate the sound to the inducer or blower motors.

 

Ok - it's a Trane XR80 model number TUD080C936K4. It was installed in June 2005.

Here is, hopefully, a picture you can view of the installation. It's laying on it's left side.

https://www.dropbox.com/s/iwvo6ye9pa...34.19.jpg?dl=0

Pardon my ignorance, but where would the vent pipe be? Would I have to remove it to see if it's clear?

I will try to isolate the location of the buzz. It's not really a buzz, it's just kind of like an electronic hum.

Let me know if you can see the photo. Photobucket no longer allows people to direct link with a free account.

The air filter is clean. Keeping in mind that the unit is laying on it's left side, would the hose you're asking me to check be on the top of the installation towards the left? In other words, on the left side of the XR80 towards the top if it were standing upright.

Thanks...

Mike

 

The compartment that contains the pressure switch hose and inducer will be located to the left of the access panel you removed in the photo you posted. The vent pipe will be the metal pipe that carries exhaust gases away from the furnace and out of the house.

The hum may be from the transformer.

 

I developed a nasty sinus infection from spending so much time in my crawlspace yesterday. I will get back with you very soon. Day or so at most. Sorry!

 

No problem. Just post back when you are feeling better. Is the condensate from the furnace draining into the crawlspace? The reason I ask is because inside the blower compartment shown in the photo you posted the cabinet appears to be very dark like it is coated with mold/mildew. That could be the reason you are having sinus problems.

If you get a chance can you post photos of the compartment where the pressure switch and inducer motor are located. You can attach photos by using the Go Advanced feature, click on manage attachments, add files, choose file, upload file and then hit done button.

 

The crawlspace wasn't damp anywhere I could see. If I had to answer I would have to say no to the condensate question.

Yes, I will get a pic as soon as I get back there. How hard is it to remove the panel that is in front of the pressure switch?

 

The panel comes off very easily. Should just lift up and out.

Question: When you set the thermostat to heat did the inducer start running. A few seconds after you call for heat you should hear it come on. It starts up and the pressure switch closes, the ignitor comes on, gas valve opens and etc. Often times the inducer won't come on after it has been sitting idle through spring and summer.

 

I still owe you a picture of the top of the unit with the panel off. I will try to get that tonight. I've been busy all day yesterday and all day today.

To answer your question, no - the only thing that happens when I call for heat at the thermostat is the click on the thermostat and then a very, very faint hum or buzzing sound. It's louder next to the unit, of course, but it's very faint from where the thermostat is.

What usually happens is that I adjust the thermostat for heat, it clicks, and then I hear the furnace coming to life. From in the house it sounds like a very faint large fan kicking on. In about 45 seconds heat starts blowing through the vents.

 

The best thing to do at this point is to check the pressure switch hose and inducer motor port to make sure they are clear. Then watch the sequence of operation at the unit itself. You can remove the access panel where the inducer motor is and then place a jumper wire between the R and W terminals on the control board. Observe what is happening with the inducer motor, if the ignitor glows, flames come on and etc.

 

Could you show me exactly where I should place the jumper wire? Never done that, so I want to make sure I do it right the first time. What kind of wire should I use?

 

I have attached your photo with the switch you will need to push in and the where the R and W terminals are located. They are side by side. You can use an opened paper clip or a small piece of thermostat wire to make the jumper. Just loosen the screws where the wires are attached and place the ends of the jumper wire between the R and W terminal. Tighten down screws, push door switch in and the sequence should be begin. Only do this test mode to see if the inducer motor starts up. ignitor glows, burners light and the blower comes on for a couple of minutes.

 

Thanks. I appreciate the help. I'll get on this...

 

Ok...getting ready to do this. I'm going to clean the clear tube coming out of the pressure switch first. When I jump the 2 circuits, do I need to remove the wires that are already under the screw, or is it ok to just add in the wire I just got to the R and W screws?

 

You also need to make sure the fitting where the clear hose attaches is clear of crud. Clean it out with a small drill bit or an opened paper clip. you can leave the existing wires under the terminals when you jumper the terminals.

Only leave the jumper in place for a short time to watch the sequence and see what is going on with the inducer motor, ignition of flames and etc.

 

Ok...

Took off the hose and it was clean. Checked both inputs to the hose with a wire and they seemed clean as well. I jumped the R and W terminals on the board and then hit that black switch and nothing happened. Just the buzz.

I just remembered something. I didn't have the 2nd panel (the top one, or on my installation the one to the left) off when I did the jump. Is it possible that I could have missed something happening behind it, even if for only a brief second?

I could jump it again if you need me too. Am enclosing pictures of the unit with the top panel off.

https://www.dropbox.com/s/uw6d5m1r0o...55.54.jpg?dl=0

https://www.dropbox.com/s/iittxmfl2e...55.30.jpg?dl=0

https://www.dropbox.com/s/s6mesasexy...55.14.jpg?dl=0

(Using this website's way to upload pictures has failed EVERY single time I've tried to use it. It always says "Upload Failed."

 

The inducer motor should have started as soon as you jumped R-W and pushed the switch in. The buzz you hear is probably the inducer motor trying to start. Does the motor feel hot when you place your hand on it? You will need to use a voltmeter to test to see if 120V is being supplied to the inducer at the IND-N and IND-H terminals on the control board. If the board is supplying that voltage then the inducer motor may need to be replaced. I have attached a portion of the wiring diagram for your unit. The terminals for the inducer motor leads are marked in red.

Sometimes you can give the inducer motor a good whack with your hand to see if it will start up. You can remove the motor and see if there is anything inside of it such as a dead bird. Some motors have oil ports you can add a few drops of oil. If so, you can use some 3-IN-ONE oil in the ports to see if it will free up. I had a mentor who would blast an inducer motor with WD-40 and it usually got it going. Worth a try anyway.

 

One one of the images that I sent, show me exactly where the inducer motor is. I think it's the thing with the black top on it. Should I hit the black thing (not beat it, but just give it a smack) or the silver fan that's attached to it?

 

Yes, it is the black part. I would try hitting the silver part also. Don't smack it too hard; just three or four times in a couple of spots. As I said I would take it apart and see if there is anything inside of the thing.

 

I gave it a few bumps in a couple of spots, but nothing happened. I tried turning it (counter-clockwise, which is the way it spins) and it would move, but not very well. It would go a whole rotation or so and then stop, making some noise (metallic noise) while it did it. I jumped the board again and tried spinning it and it looked like it was trying to get going but just wouldn't go. It didn't get hot, and the humming is definitely coming from the inducer.

It's really late, so I need to hit it, but I didn't see any spots where I would oil it. The video doesn't match the one on my unit, but thanks for sharing it. There might be some ports, but I didn't see any. Is it worth another look? Would you like me to make a video of it spinning? Would that help?

Thanks....

 

Since it is turning somewhat it appears you are getting voltage to the motor. Rotation should be CW. That motor is different than most inducer motors. It sounds like it is definitely bad and a replacement assembly will be required. The part number shown on your inducer is 70580261 and is available here: http://www.amazon.com/Furnace-Induce.../dp/B000NKWFZ0

Fasco A260

The part number listed as a replacement is: BLW01312. A Fasco A143 should also work. I advise you to verify those numbers on your own and to shop around as prices vary considerably.

 

Is this something I could do on my own? It doesnt appear that difficult with only 2 wires to attach. Do I need to be concerned with any typeof sealant between the new unit and the furnace? Also...is there any place I could buy this in a store?

 

Yes, you should be able to replace it yourself. There is probably a gasket that may have to be replaced. You won't know until you remove the part. If this is a replacement motor, the installer may have used a gasket making material. Is this the original or a replacement inducer that went bad? I doubt if you can buy it at a store but I can't say for sure. The type of businesses that sell this type of part usually only sell to licensed professionals. In my opinion, you are better off getting it on the internet and probably at a better price.

 

This is the original motor. Your link to the replacement is the cheapest i can find. There is a gasket there. It looks like its wax. You can see it in the pix I sent.

What are the dangers in doing this? I will turn it off before I try to do anything. do I need to shut off the gas too? Dont know where the shut off valve is for gas.

 

What I am saying is that when you remove the part the gasket may rip and only leave a portion of it behind. A lot of times a new gasket is included when you purchase an inducer assembly. Some installers use high temperature RTV silicone to seal the assembly. It is always a good idea to turn off the gas when working on a furnace. Turn off electrical power also. The shutoff is usually on the gas pipe coming from the meter to the furnace. Follow the pipe that comes into your gas valve inside the furnace. There should be a quarter turn valve somewhere on that pipe. If you don't see a valve then you can turn the gas off right on the meter.

Not knowing where a gas shutoff is (in case of an emergency) is not a good thing.

 

Victory! It's working now. I went down there again tonight because you said the fan turns clockwise and I wanted to spin it that way when my wife would start it up. Well, it actually does spin counter-clockwise. She started it and I spun it a bit and it started moving counter-clockwise and then started making some sort of clunking noise, like it was hitting something. I had my wife turn it off and I noticed that the fan was now spinning more freely, so I had her start it up and the fan came to life.

There must have been something stuck in the blade of the fan or near it. Anyway, we have heat now! Started it up twice and let it run for a bit and it sounds and feels fine.

You're right - I do need to learn where the gas shut off valve is. I will. I will probably just learn where the outside one is, which should be very easy to locate.

Thanks a ton - you just saved us hundreds of dollars!

One last question - if I would have had to replace this unit, it looks like I would only have to remove the motor since the fan lives outside the piece that is screwed into the furnace. I wouldn't have to remove the part that is up against the furnace with the gasket between it...right?

 

I'm glad to hear it worked out for you. I would still suggest removing the inducer assembly to see if there is something still inside the inducer. Obviously, there was. It might have been rust and it finally broke free by rotating it backwards.

Yes, sorry I confused you. The rotation at the end of the shaft is CW. It is obvious which way it has to spin to exhaust the hot gases through the vent pipe. Many of the inducer assemblies have an arrow that shows proper direction. I have drawn arrows on the attached photo to show you what I mean.

This part is usually sold as an assembly. The whole metal shroud is taken off. There are 5 screws that you have to remove to pull it off. I have attached a photo of how it appears from the backside.

You might be able to just replace the motor. You could take the inducer assembly to an electric motor shop to see if they can repair/replace the motor.
They can usually replace the bearings as well.