Forums | Home Repair | Home Improvement | Painting | Interior Decorating | Remodeling | Landscaping


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

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

Reply
 
Thread Tools Search this Thread Display Modes
Old 12-04-2011, 10:41 AM   #1
Newbie
 
Join Date: Dec 2011
Posts: 8
Share |
Default

Gas fireplace burns, then shuts down


I have a Majestic direct vent gas fireplace. Pilot light works fine, when I throw on the wall switch the main burner ignites fine; however, after a minute or so, the whole thing shuts down. The pilot will re-light without problem and the whole sequence can be repeated ad infinitum. There is a perceptible "click" when the unit shuts down (i.e. the gas stops flowing). Gas repairman replaced the thermocoupler saying that it was a guessing game as to what was wrong. That didn't help. He now says the only other thing it can be is the valve assembly itself. Before I make that investment, I'd like to hear the thoughts of others on this.
To add to the mystery, the burner stayed lit for several hours a couple of days in a row. I actually had to turn it off. But now, its back to the same routine. Any suggestions are appreciated.
mmvillar is offline   Reply With Quote
Old 12-04-2011, 10:53 AM   #2
AKA HVACTECHFW
 
Join Date: Nov 2010
Location: NE Indiana
Posts: 2,313
Blog Entries: 1
Default

Gas fireplace burns, then shuts down


check the exhaust and intake they may be partially plugged. Make sure the flame is engulfing the t-couple the whole time during the burn. The pilot may just need cleaned.
__________________
IT IS WHAT IT IS
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
hvactech126 is online now   Reply With Quote
Old 12-04-2011, 11:24 AM   #3
Member
 
biggles's Avatar
 
Join Date: Jan 2008
Location: Long Island
Posts: 3,575
Default

Gas fireplace burns, then shuts down


remove the stat off the subbase jump R to W if it gives you a steady run ....remove the jumper then go down to the furnace and jump the R to W should get the same constant run till you pull the jump..if you get a shutdown with the furnace juming then something inside is knocking the gas out..get back with yes or no's...note on jumping you are acting like the thermostat by having it on or off....it's just a control circuit closure like a light switch nothing is going to heat unless R and W connect or are rubbing on each other away from the stat..anybody nail into the wall lately
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

Last edited by biggles; 12-04-2011 at 11:31 AM.
biggles is offline   Reply With Quote
Old 12-04-2011, 11:32 AM   #4
AKA HVACTECHFW
 
Join Date: Nov 2010
Location: NE Indiana
Posts: 2,313
Blog Entries: 1
Default

Gas fireplace burns, then shuts down


Quote:
Originally Posted by biggles View Post
remove the stat off the subbase jump R to W if it gives you a steady run ....remove the jumper then go down to the furnace and jump the R to W should get the same constant run till you pull the jump..if you get a shutdown with the furnace juming then something inside is knocking the gas out..get back with yes or no's...note on jumping you are acting like the thermostat by having it on or off....it's just a control circuit closure like a light switch nothing is going to heat unless R and W connect or are rubbing on each other away from the stat..anybody nail into the wall lately
maybe you missed that it is a direct vent FIREPLACE and uses a WALL SWITCH!!!!!!!!
__________________
IT IS WHAT IT IS
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
hvactech126 is online now   Reply With Quote
Old 12-04-2011, 12:42 PM   #5
Member
 
biggles's Avatar
 
Join Date: Jan 2008
Location: Long Island
Posts: 3,575
Default

Gas fireplace burns, then shuts down


sorry about that ....WEAK transformer.....
__________________

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
biggles is offline   Reply With Quote
Old 12-04-2011, 02:33 PM   #6
Newbie
 
Join Date: Dec 2011
Posts: 8
Default

Gas fireplace burns, then shuts down


Thanks, guys, I'll try those things. Gas tech guy who came out said there was no transformer. Is the only electricity in this thing generated by the heat?
mmvillar is offline   Reply With Quote
Old 12-04-2011, 03:43 PM   #7
how
Member
 
Join Date: Feb 2011
Location: Vancouver BC
Posts: 1,473
Default

Gas fireplace burns, then shuts down


I think have a milli volt powerpile driven fireplace. That means that only 1/2 of a volt powers the gas valve, the wall switch, the wiring and a high limit button. Any wiring connections that are not perfectly tight will cause problems. Check every connection you can find.
Do you have both a thermopile 1/2" thick and a thermocoupler 1/8" thick in the pilot flame?
The flame has to envelope the power pile/ thermocoupler during the entire heating cycle and any draft that pulls the pilot flame away from either will cause the gas valve to lock out.
A picture of the pilot assy would help.
how is offline   Reply With Quote
Old 12-05-2011, 06:43 PM   #8
Newbie
 
Join Date: Dec 2011
Posts: 8
Default

Gas fireplace burns, then shuts down


Following suggestions, I've cleaned the pilot orifice and made sure all elect connections are tight. I tried to attach a photo of the pilot assembly while lit but the size exceeded the website limit. (I'll try to fix that)
The thermopile/generator (the thing in the foreground) was replaced by the gas mechanic. The pilot flame engulfs the thermocoupler and makes full contact with the tpile but I can't say it engulfs it. I tried turning what looked like an adjustment screw labeled "pilot" but the flame didn't go up or down. Again, the pilot light will burn forever and the burner never fails to ignite and burn for a time; however, within a couple of minutes it clicks and everything shuts down. Thanks for your help.
mmvillar is offline   Reply With Quote
Old 12-05-2011, 06:54 PM   #9
how
Member
 
Join Date: Feb 2011
Location: Vancouver BC
Posts: 1,473
Default

Gas fireplace burns, then shuts down


I would try bypassing the wall switch at the gas valve with a pigtail ( a wire with allligator clips at both ends). Can you identify the two wall switch wires that are connected to your gas valve?

A picture or the gas valve & pilot assemble really would help.
how is offline   Reply With Quote
Old 12-13-2011, 08:39 PM   #10
Newbie
 
Join Date: Dec 2011
Posts: 8
Default

Gas fireplace burns, then shuts down


I'm back!
I have replaced the whole valve assembly and my repairman has replaced the thermopile twice! Things worked okay for 20 mins, the repairman left and the whole thing shut down (burner and pilot). I put a voltmeter on the thermopile leads and discovered that the voltage stays stable with the pilot on- and no burner. But, when I switch on the burner, it lights and the thermopile voltage then starts dropping- very slowly- but then it hits a threshold and shuts the system down.
I can re-light the pilot, the voltage builds up but when I light the burner, the voltage drops, system shuts down, etc etc.
I'm afraid the electrical component of this problem is over my repairman's head....and also over mine. Any ideas on why this is happening?
mmvillar is offline   Reply With Quote
Old 12-13-2011, 08:41 PM   #11
Newbie
 
Join Date: Dec 2011
Posts: 8
Default

Gas fireplace burns, then shuts down


btw, I did bypass the wall switch with a pigtail but that was no solution.
mmvillar is offline   Reply With Quote
Old 12-13-2011, 09:10 PM   #12
how
Member
 
Join Date: Feb 2011
Location: Vancouver BC
Posts: 1,473
Default

Gas fireplace burns, then shuts down


Can you see the pilot flame around the thermopile when the main burner comes on. Move a log to make it visable if you have to. Is that pilot flame getting smaller, becoming softer, more yellow with the burner on when that dcmv output starts dropping?
and..
How many wires are connected to your gas valve?
how is offline   Reply With Quote
Old 12-14-2011, 05:59 AM   #13
Newbie
 
Join Date: Jan 2009
Posts: 9
Default

Gas fireplace burns, then shuts down


fireplace vent needs to have a restricter plate inserted in the venting to keep flames from lifting off the pilot assembly. restrictor plate is a round disk with a 3 inch hole in the center of it.

Last edited by oldguy2; 12-14-2011 at 06:01 AM. Reason: spell check
oldguy2 is offline   Reply With Quote
Old 12-14-2011, 02:09 PM   #14
Newbie
 
Join Date: Dec 2011
Posts: 8
Default

Gas fireplace burns, then shuts down


Here's more info based on your inputs:
I cannot see any change in the flame that hits the thermopile when the burner kicks on and I can't see a change just before everything shuts down. Like I said before, I do see a slow voltage drop from the thermopile to the point where it shuts down. While the pilot flame looks "healthy" to me, I'm not a gas repair guy. The flame hits the thermopile and sort of bends upward vertically. It stays in contact with the tp but is only hitting one side. That apparently is sufficient to get the voltage up to where the valve will open, but then something I cannot see happens. (Again, this is the second new tp put in). Also, there are 2 pairs of wires going to the valve. One pair from the thermopile and one pair from an on/off switch.
(i.e. there is no overheat sensor or anything like that)

Regarding the venting. This is a direct vent to a 4 inch vent pipe, up through the roof. Does this restrictor you mention close it down to a 3 inch pipe? I presume this is to cut down on the "draft" and keep the flame more stable?? Once again, while the flames lick and move, they don't appear to be blowing excessively and they are not lifting off the pilot.
I appreciate you guys giving me your ideas. I'm fresh out.
mmvillar is offline   Reply With Quote
Old 12-15-2011, 05:24 AM   #15
Newbie
 
Join Date: Jan 2009
Posts: 9
Default

Gas fireplace burns, then shuts down


you just gave yourself the answer to your problem.the flame turns toward thermocouple and then goes vertically.that restricter plate will slow down your draft. keeping the flame on the thermocouple.its a 10 dollar part.
oldguy2 is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
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
Need opinions on tearing out old fireplace Dwillems Building & Construction 9 09-06-2011 11:37 AM
Fireplace construction question scottyv81 General DIY Discussions 1 01-29-2011 09:26 AM
Fireplace Smell ...help wanted ! jasonb72 General DIY Discussions 6 08-26-2010 06:02 PM
New project: removal of old fireplace-replace with a new fireplace! MrShadetree0222 Building & Construction 14 10-16-2008 06:12 PM
Possible to build direct-vent fireplace? DIYerself General DIY Discussions 3 12-22-2007 10:07 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.