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View Full Version : Trane XL80 not working after tstat change out to Honeywell 3100C


Upgrade61
Dec 21, 2007, 11:13 PM
I just changed out my thermostat from an old mercury thermostat to a Honeywell 3100 which is supposed to work with a heat pump.

After I hooked it up the first time it would only heat my house in Em Heat mode. In my attempt to get the thermostat to work in normal heat mode I "fixed it" to where it will not run fan, heat, cool or them heat at all.

I tried putting the old thermostat back on on and still nothing will work.

It's supposed to get really cold in the next day or two so any help or suggestions will be much appreciated.

(I have also have attached some pictures of my current setup so you can see if I am doing something wrong or if you would like to point out something.)

Unithttp://ben-rice.com/name.jpg

Modelhttp://ben-rice.com/model.jpg

New Thermostathttp://ben-rice.com/tstat.jpg

HVAC http://ben-rice.com/hvac.jpg

acetc
Dec 22, 2007, 08:33 AM
Looks to me that you don't have the common "C" wire connected, you need this wire connected unless you install a thermostat that uses batteries, in the process of changing thermostats you may have shorted out the transformer in the furnace, try touching the red wire to the green wire, the fan should come on if the transformer is good.
Somewhere the wires change from hard wire at the thermostat to low voltage wires at the furnace, the "C" wire at the thermostat should be the same color at the furnace "C" but may change color where they spliced the hard wire to the low voltage wire to the furnace.
The transformer is the part on top of the electrical control box in the furnace, if you replace the transformer or thermostat be sure to kill the power to the furnace .
It looks like you need to clean the burners as well due to the rust in the bottom of the furnace, propane furnaces can be very dangerous when they don't burn properly, Good luck, Mike

Upgrade61
Dec 22, 2007, 09:13 AM
The thermostat is battery powered, So I should not need a C... I tried touching the red to the green and the fan did not run... I am now trying to indentify what is the transformer, so I can replace it.

ACETC, THANKS FOR YOUR HELP!

acetc
Dec 22, 2007, 09:24 AM
In your picture the transformer is the black and silver part on top of the control box, remove the box cover and you will see the wires going into the transformer, mark the wires before you take them apart so you put them back properly on the new transformer. The transformer will be 115 volts on the primary side and 24 volts on the secondary side ,40VA . Mike

Upgrade61
Dec 22, 2007, 07:46 PM
I changed out the transformer and I now have heat!!

THANKS FOR YOUR HELP!!

Now I am on to my next issue... My heat will only run in Em Heat Mode...
You see how I have it wired above, what can I do to fix this issue?

labman
Dec 22, 2007, 08:51 PM
Glad to see Acetc around and giving his usual good answers.

See https://www.askmehelpdesk.com/heating-air-conditioning/heating-cooling-maintenance-repair-troubleshooting-frequently-asked-questions-58313.html
Read about locating the control wiring fuse. If your system doesn't have one, add an inline one. Not sure what you paid for your transformer, but you can buy the inline fuse holder and a whole pack of fuses for a lot less.

acetc
Dec 23, 2007, 05:06 PM
A great suggestion adding a fuse (Labman).You say you have a heat pump and you show a picture of a gas furnace, is the furnace the second stage and air mover for the heat pump? If you don't have a heat pump then this is not the correct thermostat, do you have a control panel that mates the heat pump to the gas furnace?Follow the thermostat wires to this controller and see what wires connect to what, and get back and let us know, Thanks, Mike

Upgrade61
Jan 6, 2008, 09:19 PM
I do have a heat pump on the side...
Here is a pic... I also have no ac now...
http://ben-rice.com/heatpump.jpg

I have also updated the thermostat wiring picture at the top of this thread.

The white wire is running back into the heat pump box to W1. The tan wire is not wired to anthing in the heat pump box, it looks like it is running to the outside unit.

At this point heat only works in them heat and the cooling does not work at all.

Upgrade61
Jan 17, 2008, 07:38 AM
At this point heat only works in em heat and the cooling does not work at all.


Can someone help me with this?

therinnaiguy
Jan 17, 2008, 02:08 PM
Look for a fuse in the system that may have blown. Always shut off the power when changing a thermostat.