Curious What Comments Might Post Regarding This Potentially Dangerous Situation. - HVAC - DIY Chatroom Home Improvement Forum
Advertisement


Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Like Tree3Likes
Reply
 
Thread Tools
Display Modes
Old 03-12-2017, 10:48 AM   #1
Member
 
Join Date: Aug 2009
Location: Southwest Ohio
Posts: 1,322
Rewards Points: 2,034
Default

Curious what comments might post regarding this potentially dangerous situation.


I removed a blower ass'y from an old standing pilot mobile home furnace/propane burner that has about a 3" tall pilot flame. Furnace has been shut down because the bad blower motor won't be replaced till tomorrow.

The pilot fame on this furnace (not the one below) is about 3" tall. Maybe someone made it larger by improper cleaning? Or maybe proper pilot adjustment just drifts over time? Or can larger flame result from only from increased supply pressure? Will be checking inlet/outlet pressures first regardless, then attempt to adjust pilot flame if still needed.

I went googling in search of general comments about a 3" tall pilot flame. One of the results:

https://www.ridgidforum.com/forum/me...ge-pilot-light There are some interesting replies (at least to me) in that forum.

The original post of that link:
"Tonight I had to replace a thermocouple on a boiler as the old thermocouple failed. After replacing the thermocouple and lighting the pilot I observed it was an unusually large pilot. The thermocouple glowing a dull red. I pointed this out to the owner, and offered to get a smaller pilot orifice on Monday.

Then since the owner didn't know how to light their pilot light so I decided to show them. That's when I learned something myself. I turned the gas valve to "off" so the pilot shut down. Then I showed them how the gas valve knob couldn't be depressed in either the "off" or "on" position. However, once I turned the gas valve to the "on" position even though I couldn't depress the button the gas poured into the combustion chamber!! This was perhaps 10 seconds after I had shutoff the pilot light. I turned the gas valve to the "off" position, and then back "on" and gas poured into the combustion chamber again. I repeated the process again with the same result.

Perhaps thirty seconds later I heard a click. I turned the gas valve to "on". No gas entered the combustion chamber. The click was the pilot solenoid valve finally shutting. I suspect that even without the pilot light operating thermocouple was so hot it kept producing sufficient voltage to keep the solenoid energized for nearly a minute after the pilot was out.

This situation can permit the development of a potentially catastrophically explosive situation. If the pilot light were extinguished for any reason, and the thermostat called for heat anytime within the next 45 seconds the main gas valve can open and allow gas into the combustion chamber without a controlled ignition source."
_____________________________________
__________________
Thx, Ducky

Last edited by justplumducky; 03-12-2017 at 11:13 AM.
justplumducky is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 03-12-2017, 11:24 AM   #2
Property Mgt/Maint
 
Join Date: Mar 2015
Location: Upstate NY
Posts: 6,190
Rewards Points: 7,624
Default

Re: Curious what comments might post regarding this potentially dangerous situation.


The 3" pilot is probably the result of being set up for NG, which would use larger orifices and less pressure than propane.

I would say you need a qualified tech in there before the unit is returned to service.

Propane is heavier than air, so it can fill up a basement and cause a major problem.
Yodaman is offline   Reply With Quote
The Following User Says Thank You to Yodaman For This Useful Post:
justplumducky (03-13-2017)
Sponsored Links
Advertisement
 
Old 03-12-2017, 01:11 PM   #3
JUSTA MEMBER
 
Join Date: Feb 2014
Location: Central Wyoming
Posts: 13,323
Rewards Points: 1,612
Default

Re: Curious what comments might post regarding this potentially dangerous situation.


I'm thinking that you need to get the pilot orifice repaired for this.

I have seen people clean old pilot orifices with a Cutting torch tip cleaner, and open up the hole too large and cause an oversized pilot flame, then later have it fail completely, and cause "backfires".

Where it would sputter and pop on and off.

Get the pilot orifice replaced A S A P.


ED
de-nagorg is online now   Reply With Quote
The Following User Says Thank You to de-nagorg For This Useful Post:
justplumducky (03-13-2017)
Sponsored Links
Advertisement
 
Old 03-12-2017, 05:42 PM   #4
Member
 
Join Date: May 2015
Location: Canada
Posts: 8,058
Rewards Points: 80
Default

Re: Curious what comments might post regarding this potentially dangerous situation.


Depending on the gas valve, the cheaper ones don't actually use a regulator for the pilot port. Just an adjustment throttle screw. Upsteam pressure changes will effect the pilot on these.

PS. That guy's gas valve is starting to stick. It causes a longer then normal drop out time. 15-30sec however isn't so abnormal for old units. They considered that safe back then. (there's some logic to it)

Improperly cleaning orfices can cause this too. Like others have mentioned.

Cheers!
supers05 is offline   Reply With Quote
The Following User Says Thank You to supers05 For This Useful Post:
justplumducky (03-13-2017)
Old 03-26-2017, 09:46 PM   #5
Member
 
Join Date: Aug 2009
Location: Southwest Ohio
Posts: 1,322
Rewards Points: 2,034
Default

Re: Curious what comments might post regarding this potentially dangerous situation.


No PRESS IN tap on this unit's gas valve (only PRESS OUT), so I put together a Black Iron 1/2" FT Tee adapted down to 1/8" for my brass manometer barbed nipple fitting. But now owner is resisting going forward with my plan to check supply pressure, notify his gas company if it's too high; if not too high, pull the burner ass'y & install a new orifice, because pilot adjustment didn't affect flame at all.

He's resisting for a ridiculous reason. He wanted me to come over to his home and explain in person my above plan because he didn't understand well enough my original text message explaining my plan. When I found out I couldn't get a new pilot burner from my supplier for 3 to 5 days, I didn't want to go over on Friday after his work and explain in person, but sent another text for his son to translate for him. He's not happy about me not going over to his home to explain and has put me off now indefinitely.

Someone told me a 3" pilot flame (old mobile home standing pilot furnace, propane burner) is over firing this furnace and could be dangerous. Maybe someone in here told me that also, but also a retired tech on youtube said the same thing.

If this is truly a big problem, I want to let this guy know what the consequences could possibly be. I usually ask "how long has this been going on" when arriving for any condition I've been called out for, but failed to do it for this one. He knew he had the 3" flame before I saw it, and must have been talking to someone about it before I arrived to R&R his blower motor, cause he knew one of the possibilities for the 3" flame was that someone may have tried to clean it improperly. This guy I've known for a while and he would have never known about that unless he had already talked to someone about it, but I never asked him about that yet either (who talked to him and how long ago).

Youtube guy said pilot orifice could be for NAT GAS ?

Why is it dangerous? What could happen? CO and/or soot? Seems that CO is a result of unburned fuel and soot is a result of not enough air in the mixture.
__________________
Thx, Ducky

Last edited by justplumducky; 03-26-2017 at 10:12 PM.
justplumducky is offline   Reply With Quote
Old 03-26-2017, 10:28 PM   #6
Member
 
Join Date: May 2015
Location: Canada
Posts: 8,058
Rewards Points: 80
Default

Re: Curious what comments might post regarding this potentially dangerous situation.


Lol.... "customer relations... "
Customer really isn't always right...

If the pilot it's overfiring a bit, it'll consume more fuel. Depending on the type of pilot, it can be a bit short on primary air, causing CO. (not all pilots will do that though.) Since it's a MH, the total air volume is less, which could potentially lead to a situation with high CO/CO2 levels. (it's slim, but it's rated and designed a certain way, and exceeding that promotes those less common situations.)

Cheers!
justplumducky likes this.
supers05 is offline   Reply With Quote
The Following User Says Thank You to supers05 For This Useful Post:
justplumducky (03-26-2017)
Old 03-27-2017, 05:18 AM   #7
An old Tradesmen
 
Join Date: Oct 2008
Location: Somewhere
Posts: 38,472
Rewards Points: 8,706
Default

Re: Curious what comments might post regarding this potentially dangerous situation.


Large pilot flames are a waste of gas. Sometimes, someone will increase pilot flame thinking its being blown out by wind, when its the thermocouple that is getting weak. Then when a new thermocouple is installed, the pilot is not reset. And thermocouples burn out every few years.

The hotter the thermocouple gets, the longer it takes to drop out the gas valve.
justplumducky likes this.
__________________
When posting in certain forums, knowing your location will help others give better feedback/advice/solutions to your questions.
beenthere is online now   Reply With Quote
Old 03-27-2017, 06:34 AM   #8
Member
 
Join Date: Aug 2009
Location: Southwest Ohio
Posts: 1,322
Rewards Points: 2,034
Default

Re: Curious what comments might post regarding this potentially dangerous situation.


Quote:
Originally Posted by beenthere View Post
Large pilot flames are a waste of gas. Sometimes, someone will increase pilot flame thinking its being blown out by wind, when its the thermocouple that is getting weak. Then when a new thermocouple is installed, the pilot is not reset. And thermocouples burn out every few years.

The hotter the thermocouple gets, the longer it takes to drop out the gas valve.
Cool beans.... more ammunition to hit 'im with regarding taking care of this pilot flame, before it results in him & his family losing his heat (middle of the night) in the worst part of winter.

I've heard many different estimates for how long thermocouples will last with proper flame characteristics. Grateful for another...
__________________
Thx, Ducky
justplumducky is offline   Reply With Quote
Old 03-27-2017, 08:25 AM   #9
Hvac Pro
 
yuri's Avatar
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 21,750
Rewards Points: 1,632
Default

Re: Curious what comments might post regarding this potentially dangerous situation.


10 years.
__________________
"Cut it twice and it is still too short".
yuri is online now   Reply With Quote
The Following User Says Thank You to yuri For This Useful Post:
justplumducky (03-27-2017)
Old 03-27-2017, 09:02 AM   #10
Member
 
Join Date: Aug 2009
Location: Southwest Ohio
Posts: 1,322
Rewards Points: 2,034
Default

Re: Curious what comments might post regarding this potentially dangerous situation.


Quote:
Originally Posted by yuri View Post
10 years.
Wow, that's the longest I've ever heard! You wouldn't "put me on" would ya Master?
__________________
Thx, Ducky
justplumducky is offline   Reply With Quote
Old 03-27-2017, 09:39 AM   #11
Hvac Pro
 
yuri's Avatar
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 21,750
Rewards Points: 1,632
Default

Re: Curious what comments might post regarding this potentially dangerous situation.


Nyet.

They last the life of a lot of hot water heaters. Those can go 10-15 yrs. In the old days the tanks lasted that long.

I worked on thousands of Lennox G8 series furnaces and they had a T shaped pilot burner hood. Deflected the flame horizontally left and right. One side to the thermocouple and the other to the burners.

Nice soft not harsh flame and thermocouples always lasted at least 10 yrs. The end of it should NOT be glowing red hot but dull black if I remember setup info from Honeywell correctly.

If it is red and harsh it cuts the end off and may create to much of a temp difference between the hot and cold junctions inside of it/stress.
__________________
"Cut it twice and it is still too short".

Last edited by yuri; 03-27-2017 at 09:46 AM.
yuri is online now   Reply With Quote
The Following User Says Thank You to yuri For This Useful Post:
justplumducky (03-27-2017)
Old 03-27-2017, 03:36 PM   #12
Member
 
Join Date: Aug 2009
Location: Southwest Ohio
Posts: 1,322
Rewards Points: 2,034
Default

Re: Curious what comments might post regarding this potentially dangerous situation.


[QUOTE=yuri;4104017]Nyet.

They last the life of a lot of hot water heaters. Those can go 10-15 yrs. In the old days the tanks lasted that long.I worked on thousands of Lennox G8 series furnaces and they had a T shaped pilot burner hood. Deflected the flame horizontally left and right. One side to the thermocouple and the other to the burners.

Nice soft not harsh flame and thermocouples always lasted at least 10 yrs. The end of it should NOT be glowing red hot but dull black if I remember setup info from Honeywell correctly.

If it is red and harsh it cuts the end off and may create to much of a temp difference between the hot and cold junctions inside of it/stress.
Attached Images
 
__________________
Thx, Ducky
justplumducky is offline   Reply With Quote
Old 03-27-2017, 04:04 PM   #13
Hvac Pro
 
yuri's Avatar
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 21,750
Rewards Points: 1,632
Default

Re: Curious what comments might post regarding this potentially dangerous situation.


These straight type can be harsh and cut off the tip of yer tcple.
Attached Images
 
__________________
"Cut it twice and it is still too short".
yuri is online now   Reply With Quote
Old 03-27-2017, 04:22 PM   #14
An old Tradesmen
 
Join Date: Oct 2008
Location: Somewhere
Posts: 38,472
Rewards Points: 8,706
Default

Re: Curious what comments might post regarding this potentially dangerous situation.


Yep, should get 10 plus years out of one with proper pilot flame on it.
__________________
When posting in certain forums, knowing your location will help others give better feedback/advice/solutions to your questions.
beenthere is online now   Reply With Quote
The Following User Says Thank You to beenthere For This Useful Post:
justplumducky (03-27-2017)
Old 03-27-2017, 04:26 PM   #15
Member
 
Join Date: Aug 2009
Location: Southwest Ohio
Posts: 1,322
Rewards Points: 2,034
Default

Re: Curious what comments might post regarding this potentially dangerous situation.


I googled for Lennox G8 series T-shaped pilot burner.
Attached Thumbnails
Curious what comments might post regarding this potentially dangerous situation.-t-shaped-pilot-burner-furnaceg.jpg  
__________________
Thx, Ducky
justplumducky is offline   Reply With Quote
Sponsored Links
Advertisement
 
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tiling vertical post kellyharris15 Flooring 12 02-22-2011 04:28 PM
Deck Post Height for Composite Post Railing ylwdog Building & Construction 5 11-15-2010 10:01 AM
6x6 Cedar post rot stanltod Carpentry 2 06-21-2009 05:54 PM




Top of Page | View New Posts