How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask M Oglesby Your Own Question
M Oglesby
M Oglesby, HVAC Technician
Category: HVAC
Satisfied Customers: 2038
Experience:  Universally Certified HVACR Technician
27079509
Type Your HVAC Question Here...
M Oglesby is online now
A new question is answered every 9 seconds

Trane furnace not working!

This answer was rated:

I have a Trane furnace that is not working. I have followed the instructions on the panel to restart the furnace, but it did not make a difference. I have also tried turning my fan on the thermostat to "on", but the fan does not switch on for heat or cool. The diagnostic light is not lighting up, but the furnace does make a humming sound, so it appears that it is getting power. We had VERY high winds yesterday, which could be a factor.

Heath :

First thing to do is go to the furnace and take off the lower blower door and locate the circuit board and turn the power off to the furnace. In the circuit board there should be a small car like fuse usually 3 or 5 amps, check the fuse it is probably blown. Replace the fuse with the same amperage fuse and then turn the power back on the furnace and check the operation of the furnace.

Full Size Image
JACUSTOMER-57h4rn9h- :

I understand what you are saying. I have turned off the power and located the circuit board, but I don't see the fuse. Would it be enclosed in something? I don't see it on the diagram either.

Heath :

No it should be right in the circuit board pushed into it. There should be a fuse somewhere that protects the low voltage side of the transformer. That sounds like what is blown, that is why the blower won't come on when you put the thermostat fan switch in the on position.

JACUSTOMER-57h4rn9h- : Still don't see the fuse on the board itself. When I look at the diagram, I do see the yellow 3 wire connects to a fuse link and the yellow 4 wire connects to another fuse link. These connect to little round brown things (I'm guessing are the fuses). Could that be it?
Heath :

Could be can you take a picture and post it so I can get a better look at it.

JACUSTOMER-57h4rn9h- :

Here is a pic of the control panel and the fuse links

JACUSTOMER-57h4rn9h- :
fuse link 1
Full Size Image
Heath :

The things you are calling a fuse links are actually flame rollout switches. Most times these have a red reset button on the back between the wires if pressed in it resets the switch. I didn't see the reset in the pictures. If you have access to an electric meter with the power off set the meter to ohms and check to see if the switches are open. or you can us an unbent paper clip and take the wires off the switches and us the paperclip to jump the two wires together. If the furnace fires with the blower dooron and the switches jumped then the switch is bad and will need to be replaced.

JACUSTOMER-57h4rn9h- : Don't have an electric meter. Tried the paper clip on both switches and no luck. Does it make sense that i do not have a fuse on the control panel? Anything else I can try? Really appreciate your help.
Heath :

Trying using the paper clip at the circuit board to jump the red or R terminal to the W terminal and then press the door switch in and see if the furnace fires.

JACUSTOMER-57h4rn9h- : No luck. It just hums, no fire or fan
Heath :

it has to be the circuit board then Is there an inducer motor near where the chimmney attaches to the furnace?

JACUSTOMER-57h4rn9h- : I think so. There is a fan that looks like it is supposed to blow air out the exhaust tube
Heath :

Is there a way you can try and turn it to see if it spins freely?

JACUSTOMER-57h4rn9h- : Yes. It spins freely
Use a voltmeter to see if the inducer fan motor is receiving 120 volts while the R and W wires are jumped.
Customer: replied 5 years ago.
I dont have a voltmeter. Is there something else I can try?

At this point, we need to find out if the control board is responding to the thermostat on a call for heat. When heat is called for, the first thing to turn on is the inducer fan motor. So we need to verify if the control board is sending power to the inducer fan motor to see if it is coming on. If it is not sending power, then the control board is bad. If it is sending power, then the inducer fan motor is bad. The only way to test is to have a voltmeter to see if the inducer fan motor is receiving power.

M Oglesby, HVAC Technician
Category: HVAC
Satisfied Customers: 2038
Experience: Universally Certified HVACR Technician
M Oglesby and 2 other HVAC Specialists are ready to help you