replacing thermal coupler

Old 10-31-04, 01:10 PM
Thread Starter
Join Date: Oct 2003
Posts: 60
Received 0 Votes on 0 Posts
replacing thermal coupler

The furnace I have does not turn on, the gas is on and the guy that turned on the gas relit the pilot and said it didn't stay on, and that he thought i needed a new thermal coupler. i know nothing about furnace stuff and was wondering if this is something I can do, and how to do it. I am fairly handy around the house but haven't done any furnace work (haven't had to as of yet). The heating companies I called said it is at least 80$ just to come out.

Thanks much.
Old 10-31-04, 01:27 PM
Sharp Advice's Avatar
Admin Emeritus
Join Date: Feb 1998
Location: The Shake and Bake State USA
Posts: 10,398
Received 5 Votes on 4 Posts
Hello bryansauer. Welcome to the Heating Furnaces forum topic and the Do It Yourself Web Site.

The thermocouple is an element that is secured into the pilot assembly where the pilot flame is. The pilot flame is heating it. The other end of the thermocouple is screwed into the gas control valve.

A thermocouple is generic except for it's length. Thermocouples are made in different lengths. Measure the removed part or take the one you remove to any hardware store and replace it with an exact duplicate in length. The parts cost is very nominal.

New thermocouple packages will contain complete do-it-yourself installation instructions and pictures. The package also contains additional clips of various assortments. None may not even be needed.

Not all the parts contained in the package with the thermocouple will be needed. The packages contain an assortment of holding parts and clips that are generic and designed to fit a wide variety of applications.

Install new T-Couple into pilot assembly exactly as the existing one is installed. Element end must be placed exactly the same height as the exiting one. Reinstall pilot assembly as found.

Gently thread nut end of T-Couple into gas control valve, starting threads by hand to insure threads will not cross thread and become damaged. Tighten nut snugly but do not overtighten. Just snugly until lightly bottoms out.

Be sure the pilot flame is all blue and no yellow. If any yellow or doubt pilot flame is correct or maybe dusty, clean it out. Blow out pilot flame & allow assembly to cool. Use can of computer keyboard canned air cleaner to blow out the entire assembly.

Relight pilot and note the result. Test the pilot again note any changes. Also be sure the T-Couple is correctly installed in the pilot assembly. Only the tip of T-Couple or about top 1/3 should be heated. Must be glowing a bright cherry red color.

If you need further assistance, use the REPLY button to add any additional information or ask additional questions after attempting the correctional method or methods offered.

Regards & Good Luck, Sharp Advice.
Web Site Host, Forums Monitor & Multiple Topic Moderator.
TCB4U2B2B Company Enterprises. Energy Conservation Consultant & Gas Appliance Diagnostics Technician.

Personal Reminder:
Buckle Up & Drive Safely.
"The Life You Save, May Be Your Own."
Old 11-02-04, 12:03 PM
Thread Starter
Join Date: Oct 2003
Posts: 60
Received 0 Votes on 0 Posts

i am having a bit of trouble installing this thermocoupler. i have removed the old one, however i cannot get the new one in the pilot bracket. the old one only was removed because the copper wire and end near the pilot became unattached (ie. the copper wire was probably cracked and when i moved it it just split into two pieces). then i pulled the old coupler end out as if it would be going thru the pilot flame if it was lit, but my directions said i should pull it out the other way (which i couldn't do, but didn't have to because the copper wire/coupler broke). Now, the new thermal coupler cannot be inserted up thru the pilot bracket, it is too big, and i can't make it go thru the other way becasue the end of the if has the threading unti to attach to the gas valve. anythoughts? the pilot bracket seems to not be unattachable so i'm not sure.
Old 11-02-04, 03:26 PM
Ed Imeduc's Avatar
Join Date: Aug 2002
Location: Mountain Williams Missouri
Posts: 18,386
Received 1 Vote on 1 Post

See if there is a nut there on the bottom of the pilot for the T/C take it out and see if it works. On the card that the T/C was on should show you how it goes in. Most fit lots of different pilots.

Old 11-05-04, 07:16 AM
Visiting Guest
Posts: n/a
thermocouple replaced, furnace now working

Dear Ed and website hosts,

Thanks for the free info on what a thermocouple is and how to replace it. I replaced the one on my mom's Montgomery Ward wall furnace and it is now working great. It saved her a lot of money.


Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: