Comments on: 3 Things to Check Before the Furnace Won’t Start!

By: Jeff

Jeff — Thu, 01 Oct 2009 17:39:57 +0000

Okay I’ll get someone in – thanks!

I’m in Spokane WA. We usually have the possibility of using at least some heat from mid-September to mid or late April. We don’t have central air although I’d love to have one. We get several weeks of upper 80s to low 100s during the summer.

By: Mark

Mark — Thu, 01 Oct 2009 17:20:02 +0000

@ Jeff –

I would lean toward the circuit board or gas valve… since the ignitor pilot is lighting up, it appears that everything is cycling right up to the point of the gas valve opening, which is not happening. Of course, it may be that the ignitor itself is not getting hot enough to tell the valve to open as well.

In ref to the swap to a Goodman 95% unit – it would probably do great as long as the blower has enough volume for your central AC unit (If you have one)! You do however have a few things to consider with venting, combustion air etc, going from an older unit to new.

I don’t know where you live – but in some cases, the cost of upgrading to a 95% AFUE unit will never pay off if you don’t use heat long enough throughout the year. Check out http://www.HVACOpCost.com to see a comparison.

By: Jeff

Jeff — Thu, 01 Oct 2009 17:10:10 +0000

Thanks. Some other things I saw online talk about a dirty pilot orifice or that the burners have accumulated enough corrosion to prevent the pilot from lighting up the runner to the burner head. I did see a lot of rust in those areas so I may try to figure out how to get to them. While researching replacements I’ve been amazed at how much smaller the units have gotten while getting so much more efficient. Do you think a 95% efficient 90K Goodman would replace our old 100K Carrier okay?

By: Mark

Mark — Thu, 01 Oct 2009 14:22:57 +0000

@ Jeff -

Sounds like it may be related to the circuit board or gas valve… The only real way to know for sure, is to have it checked by a technician.

Here is another video discussing gas furnace start sequence, maybe it will help in the troubleshooting.

By: Jeff

Jeff — Thu, 01 Oct 2009 14:09:45 +0000

I have an original Carrier 100K installed in June 1969 so I’ve been expecting to replace it for the past several years but it’s been a warrior keeping our 2000 sq foot split level plenty warm at a reasonable cost. Yesterday I tried to start it to burn off the smell that comes out when it hasn’t been used to a while & it may have finally given up. The thermostat clicks, the intermittent pilot light fires on but that’s where the sequence stops – no comforting whoosh of the burners coming on. I’ve been through many websites last night but I’m not sure what step is supposed to happen next. I watched your video How Does a Gas Furnace Work which shows the starting of an inducer fan but I’m not sure where to check that. I’m not very mechanically inclined – am I at the point of calling someone now? It’s still in the 60s here & yes, we are researching new models to replace it before winter but it would be nice to have it working until then. Thanks for all your articles -

By: Mitchell Moore

Mitchell Moore — Sat, 05 Sep 2009 05:32:03 +0000

This happens every year both in the summer and winter seasons and it shouldn’t. It never fails that the people will wait until the last minute to check the heat. People PLEASE check it out before it gets cold. It takes ONE MINUTE! Very good article. I am glad someone brought this out in the open. Keep up the informative hvac blogs. Thanks