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-   -   Trane XE80 worked yesterday - won't come on today (http://www.diychatroom.com/f17/trane-xe80-worked-yesterday-wont-come-today-129866/)

flounder 01-13-2012 10:02 PM

Trane XE80 worked yesterday - won't come on today
 
I have a fairly new Trane XE80. Probably about 5 years old. I had heat working yesterday but today, I have nothing. No lights on the indicator light. If I change the t-stat to cooling - nothing happens. If I turn the fan on, nothing.

Any idea on what to check? Kind of weird it worked yesterday but nothing today. I took the cover off an noticed the wire from the door switch is not attached to anything on the control board.

Anybody give me any ideas on what it could be?

how 01-13-2012 10:23 PM

That loose wire from the door switch will probably put 120V through anything conductive if that door switch is depressed. This is a potentially dangerous situation to play with. Turn off the furnace breaker to check it further.
Does that loose line from the door switch have a spade terminal attached to it's end, is it stripped clean to be marretted somewhere or does it look broken? I assume that one line from the door switch gets it's power from the main power feed conection box. The remaining loose line that is connected to the door switch should be connected to L1 on the mother board (if it is now empty.) Without the door switch being reconnected to the board - nothing will operate on the furnace.

Houston204 01-13-2012 10:30 PM

You may be able to tighten that spade connector so it doesn't slip off again.

http://i151.photobucket.com/albums/s...aneTUDXE80.jpg

I don't see a low voltage fuse on this diagram.

flounder 01-13-2012 10:55 PM

My door switch has one wire coming off it with a spade terminal. Terminal looks fine but I don't know where to connect it. Door switch has two prongs, one has no wire connected, the other has a wire connected to the switch but it isn't connected to anything.

Shouldn't the door switch have two wires coming off it? There is no loose wire that looks like it should connected to the door switch.

Houston204 01-13-2012 11:02 PM

http://www.homedepot.com/buy/electri...ter-93406.html

Someone probably bypassed the door switch. A non contact voltage tester will quickly prove if the board is getting power. It will not prove neutral.

If the breaker is not tripped, it is probably the transformer.

how 01-13-2012 11:07 PM

It sounds like your door switch has been disabled. The door switch should have two lines connected to it. One is the direct power feed into the furnace and the other is from the switch back to L1 on the board. The idea is that all the power to the furnace is turned off when someone opens up the door and the switch is disabled.
Your discription of the furnace is that it has no power. Look for a power switch for the furnace somewhere near the closest access door to the furnace area. It will usually look like a light switch but will be often located in a higher position. Check to see if your furnace breaker is on as well.

flounder 01-13-2012 11:10 PM

The breaker is not tripped, that is the first thing I checked. Anyway to check without that tester?

Houston204 01-13-2012 11:10 PM

How has a good point with the light switch. It is common to find this switch turned off when people are storing their winter decorations and flipping off the wrong switch when they leave the attic.

flounder 01-13-2012 11:12 PM

Quote:

Originally Posted by how (Post 821939)
Your discription of the furnace is that it has no power. Look for a power switch for the furnace somewhere near the closest access door to the furnace area. It will usually look like a light switch but will be often located in a higher position. Check to see if your furnace breaker is on as well.

I checked both of those. Flipped the breaker to be sure and the switch is up. Nobody has been up there to have flipped it off. Any other ideas? We don't store anything in the attic.

Houston204 01-13-2012 11:13 PM

I've seen a tech touch the power terminal with the fingernail side of his finger so the electricity would contract the muscle and cause him to break free if it was hot.

I prefer the tester or a meter.:laughing:

flounder 01-13-2012 11:16 PM

I'll pass on the finger nail but I do have a meter. I also have a tester with a light and two prongs. What I do check?

how 01-13-2012 11:16 PM

A 5 year old furnace will usually require an external shut off switch by code so that you could disable the furnace without endangering yourself in an emergency. If you follow the electrical feed cable for the furnace up to the ceiling, it will often then angle away in the direction of the on/off switch.

I obviously type too slow to keep up.

flounder 01-13-2012 11:18 PM

Quote:

Originally Posted by how (Post 821953)
A 5 year old furnace will usually require an external shut off switch by code so that you could disable the furnace without endangering yourself in an emergency. If you follow the electrical feed cable for the furnace up to the ceiling, it will often then angle away in the direction of the on/off switch.

There is a light switch above it with a feed coming from the unit to the switch, then out of the switch to I'm assuming the breaker. The switch is in the up position.

ben's plumbing 01-13-2012 11:18 PM

test to see that you have power to the juction box on furnace....if you do check at door switch..if you don't check connections in box...

how 01-13-2012 11:32 PM

I can't tell you how many on/off switches I've run into that are upside down. Its worth a try to put the switch in the opposite position for a moment to see if you hear anything from the furnace.
Beyond that it's metering at the junction box for power and then moving forward into the furnace if you have power or moving back to both sides of the on/off switch and towards the breaker if the furnace junction box has no power.


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