Comments on: Gas Furnace Not Starting or Starting Intermittently – How To Fix It

By: Mrs. Terry Ostlund

Mrs. Terry Ostlund — Mon, 16 Jan 2012 21:29:58 +0000

Thank you so much for the pictures. I knew what the problem was because we had the guy out a couple of years ago and he showed my husband where it was at. My husband is not due home for 4 more hours and the furnace wouldnt come on. You gave me great information and it worked the first time! Thanks again.

By: Dan

Dan — Mon, 02 Jan 2012 20:01:20 +0000

I have a Mr. Heater HSU75LP garage heater that is driving me nuts. I live in Minnesota where it gets real cold. When I want to work in my garage I turn on Mr. Heater. (I turn it on by using the wall switch). The STAT (programable)is set at 60′. The blower comes on and after about 30 sec. I hear a click (igniter)and the flames come on, sometimes. If I try turning the wall switch on and off it may light off after 2, 3, 4 or 5 times or not at all. I will go out later and go thru the same process and it lights off. After it lights it seems to operate fine for as long as I leave the main switch on. The red blinking light pulses fast and steady at all times regardless if furnace lights or not. I thought of checking the flame sensor but it looks like I have to break the sealent that runs around the gas pipe that goes from the gas valve to the burners in order to remove the burner unit that will allow me to look at the sensor and igniters. Anyone have any ideas as to what is happening?

By: Tim Mathews

Tim Mathews — Mon, 02 Jan 2012 16:45:58 +0000

Thank you so much for this article and pictures. Woke up to cold house and restarted my furnance by flicking circuit breaker . It would run for 30 secs and shut off. Although manual says Falme sensor , I had no idea it was same thing as thermocouple. Thanks for the pics. Now I now what it is. Cleaned it and now running, hopefully for good.

By: Juan

Juan — Mon, 05 Dec 2011 16:26:23 +0000

Same thing here don’t know jack about furnace but looked online and u tube and found out that the sensor needed replaced or clean so I cleaned it with a pair of pliers and now is working fine still gonna order a new part I’m not always home so can’t expect the wifey to do it and then I came across this interesting article wish I would gave read this first instead of going crazy with out heat lol happy holidays

By: Craig

Craig — Fri, 11 Nov 2011 03:16:52 +0000

My furnace was experiencing same symptoms. Cleaned flame sesnor with steel wool. It didn’t really look dirty–but it worked!! Furnace fired right up. Thanks–now we won’t freeze tonight!
Awsome Blog!

By: Ben

Ben — Wed, 09 Feb 2011 01:38:40 +0000

I was having similar problems–the furnace would work fine for awhile, then the house would get to 59 or 60 degrees even though the thermostat was set at 65. A couple of times i went down and checked the furnace and flipped the on off switch on and off and it’d fire right up. a week later I was having similar problems and did it again and again it worked for 1 heating cycle, then it wouldn’t come back on. I found the flashing code that indicated heat sensor issues and came to this web site. I pulled out my sensor and cleaned it with fine sandpaper and reinstalled it and viola–the flashing led lights went back to normal and the furnace is working fine so far! Thanks a million (and $145)

By: Brian

Brian — Mon, 31 Jan 2011 08:34:55 +0000

This is exactly what my furnace is currently doing. It is WAY too cold for this. 14 degrees at the moment. I have already tried removing and cleaning the flame sensor, but it is still not running right. Thank god I have a wood burner in my basement! I will try cleaning the flame sensor again after reading from this website and hopefully I will get better results. Either way, thanks for the info! It is good to know that there is good help out there.

By: scot

scot — Thu, 20 Jan 2011 23:35:22 +0000

This just happened to my furnace. Flames on for 15 or so seconds, then off, and it would not heat the house. I took out the little flame sensor and cleaned it off with rubbing alcohol and a pencil eraser, put it back in, problem solved. Gas repair guys (Barron Heating) wanted to charge me a hundred bucks just to come out and look!!!

On another note, I also fixed another problem with info from here a while back- the little heater element that ignites the gas was cracked and from info gained here I was also able to repair that (although the part cost was around $70 at the time, ridiculous!)

Anyway, thanks to all of you for helping me save money I can’t afford to spend!

By: Mike

Mike — Sat, 15 Jan 2011 23:56:29 +0000

Thank you thank you thank you.Easy to do and the furnace is working great.

By: Chad

Chad — Sun, 26 Dec 2010 17:07:49 +0000

This actually works, would not have believed it but here is what happened to me.
I woke the Sunday morning after Christmas to find the house unusually chilly. The thermostat read 60 degrees and indicated the heat was on, but it was not! We had family coming the next morning and the furnace not running on a weekend, is how my luck typically goes. I cycled the power to the furnace, it ran flames for a few seconds and then off. Next I did what has become the norm these days for any issues, whether it be with the house or my car or anything, I searched the internet and ran across this web site and this article. When I removed the flame sensor, it had a light white powder or surface corrosion on it. I followed what the article said about cleaning the flame sensor with steel wool and wallah!! After re-installation, the furnace fired up and heated the house on the first try!!

By: Bob

Bob — Sat, 27 Nov 2010 15:34:06 +0000

This worked for me several times over the years. My furnace LED code error message was something like “Call for heat, but no flame detected.” So if there is a call for heat (i.e., gas) but the sensor does not detect sufficient flame, it will send a signal to shut off the gas flow so my house doesn’t fill with un-ignited gas. Each time it happens you should hear the furnace blower motor for about ~30 seconds before, the actual furnace flame jets for 5-10 seconds, the flame jets stop, and the blower runs for another ~30 seconds.

I haven’t used light steel wool, but I’ve had luck with a light sandpapering, and even used a pencil eraser. The fix seems to work for months and usually gets me through the rest of the heating season.

I’ve done this for years, which is probably both good and bad. It’s an easy fix after I did it once, and it was even easy in a second house because I knew what to look for. If I knew a new flame sensor would fix it forever, I’d do that. But in the meantime, I have plenty of pencil erasers.

By: Daniel

Daniel — Sun, 07 Nov 2010 04:10:05 +0000

You just saved me a call to the hvac repair man. Just got some steel wool, cleaned off that little metal rod, fired up the first time. Thanks