Yesterday's Tractor Co.
Shop Now View Cart
   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver
Classified Ads
Photo Ads
Tractor Parts

Discussion Forums
Project Journals
Tractor Town
Your Stories
Show & Pull Guide
Events Calendar
Hauling Schedule

Tractor Photos
Implement Photos
Vintage Photos
Help Identify
Parts & Pieces
Stuck & Troubled
Vintage Ads
Community Album
Photo Ad Archives

Research & Info
Tractor Registry
Tip of the Day
Safety Cartoons
Tractor Values
Serial Numbers
Tune-Up Guide
Paint Codes
List Prices
Production Nbrs
Tune-Up Specs
Torque Values
3-Point Specs

Tractor Games
Just For Kids
Virtual Show
Museum Guide
Memorial Page
Feedback Form

Yesterday's Tractors Facebook Page

Related Sites
Tractor Shed
Ford 8N/9N Club
Today's Tractors
Garden Tractors
Classic Trucks
Kountry Life
Tool Talk Discussion Forum

Re: Furnace pilot light won't stay lit

[Show Entire Topic]  

Welcome Guest, Log in or Register
Author  [Modern View]
missouri massey man

03-12-2013 04:17:30

Report to Moderator

Quoting Removed, click Modern View to see

The thermocouple works by having the junction of two dissimilar metals heated. When heated they generate that milli voltage. The safety coil in the redundant gas valve will be held in only when the milli voltage generated by the thermocouple matches it. You are bypassing that safety coil by depressing the button long enough for the milli volts to take your place. Typically what you are describing is one of three things: 1) Bad thermocouple 2) Insufficient heat on the thermocouple end...too small of flame or flame is so high it is actually bypassing where it needs to be 3) Defective holding coil in the safety circuit.
Why possibly a bad thermocouple? We are finding poor quality of products flooding the US market in virtually everything, why not thermocouples too... Usually if the junction of the two dissimilar metals (swelled up end) of the thermocouple is intact it will generate sufficient milli voltage, but that is no longer true with the lower quality of materials.

Though a slim possibility, the same applies to the redundant gas valves holding coil. If bad, the gas valve needs to be replaced. The easiest way to check it is with another new thermocouple. This will ring true ONLY if the pilot is adjusted properly and coming in contact with the thermocouple properly.

Make sure you have a strong pilot flame encompassing a minimun of 1/2 to 3/4" of the end of the thermocouple. There should be a nice inner core of blue with a different softer and larger outer ring of blue with NO yellow. Yellow or white in the flame will indicate imminent carbon build up. A tad of orange is all right as usually that will be superficial rust particulate sucking into the flame as you are or have been disturbing the area surrounding the pilot with all your work. That will go away mostly. Please keep us informed on what you do and what you find.

[Log in to Reply]   [No Email]
Dusty MI

03-12-2013 04:29:14

Report to Moderator
 Re: Furnace pilot light won't stay lit in reply to missouri massey man, 03-12-2013 04:17:30  
I've checked thermocouples with a DC volt meter and a propane torch.


[Log in to Reply]  [No Email]
missouri massey man

03-12-2013 05:00:51

Report to Moderator
 Re: Furnace pilot light won't stay lit in reply to Dusty MI, 03-12-2013 04:29:14  
Yeah, I too have a few tricks up my sleeve and have done the same thing...I used to carry an old "Baso" switch to check the thermocouples with. Just left the pilot assembly in the furnace, unscrew the end into the gas valve and screw into the Baso and relight the pilot while holding down the redundant valve to maintain pilot gas flow. After 10 maybe 15 seconds, depress the Baso switch and if it holds in then the thermocouple was generating adequately. I have been doing commercial and industrial for the last 25 years so this old school technology (if you can call it that) is slowly going by the wayside. I probably haven't touched a standing pilot in a decade.

I was thinking he probably doesn't have a dvom and was going for the basic description of the pilot circuit sequence so the repair can be made with nothing special.
He's gotten a lot of good suggestions so far and I am confident he will figure it out.

[Log in to Reply]  [No Email]
[Show Entire Topic]     [Options]  [Printer Friendly]  [Posting Help]  [Return to Forum]   [Log in to Reply]

Hop to:

Fast Shipping!  Most of our stocked parts ship within 24 hours (M-Th). Expedited shipping available, just call! Most prices for parts and manuals are below our competitors. Compare our super low shipping rates! We have the parts you need to repair your tractor. We are a company you can trust and have generous return policies. Shop Online Today or call our friendly sales staff toll free (800) 853-2651. [ About Us ]

Home  |  Forums

Copyright © 1997-2016 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters