First time trying to use the heat this year (electronic-ignition furnace), and it just isn't firing up. It goes through the 3 attempts and then switches off. The igniter lights up, but no flame whatsoever (and yes, the gas is switched on).

I am no HVAC specialist put I had exact same problem last year. And ur turned out there was s sensor in the furance that was dirty. Got it cleaned and works as usual now.

I'm not a HVAC tech, but I had a similar issue. There is a flame sensor by the igniter that sometimes gets dirty or goes bad. If the unit doesn't sense a flame, it shuts down the unit. It also could be a stuck gas valve. Maybe tap it a couple of times. Finally, it could be a bad computer board. Just a few issues I have had over the years.

I'm not a HVAC tech, but I had a similar issue. There is a flame sensor by the igniter that sometimes gets dirty or goes bad. If the unit doesn't sense a flame, it shuts down the unit. It also could be a stuck gas valve. Maybe tap it a couple of times. Finally, it could be a bad computer board. Just a few issues I have had over the years.

 

I've had the same issue. I had to clean the flame sensor periodically. On mine, it was actually a pin in front of the flame jets that would get some carbon build-up on it from time-to-time.  I had to wipe it off with a brillo pad.

My only suggestion is use Angie's list to find the best guy in town, make an appointment instead of having to make an emergency call on a night or weekend to evade crazy charges, and if your instincts tell you not to do something, don't go for it.  

For me i have an annual maintenance contract with my gas company its like $14 a month this includes 2 maintenance  a year one for furnace one for AC and if there is a problem they come with in 24 hours and they cover the cost of all parts used. I found out furnace maintenance and parts can really add up for the maintenance contract is worth its weight in gold.

Here is an crude image showing the general area where most flame sensors are found.

Thanks for the responses. I have had the sensor issue before (where it needed cleaning), but in this case it isn't flaming up at all. I heard something about air sometimes getting in the line, but I'm not so sure.

 

I certainly won't be messing around with it too much  - I just like to have an idea before someone comes in to fix it.

 

We have separate heat upstairs, and gas fireplaces on the 1st floor and basement - so at least heat won't be a problem.

Thanks for the responses. I have had the sensor issue before (where it needed cleaning), but in this case it isn't flaming up at all. I heard something about air sometimes getting in the line, but I'm not so sure.

 

I certainly won't be messing around with it too much  - I just like to have an idea before someone comes in to fix it.

 

We have separate heat upstairs, and gas fireplaces on the 1st floor and basement - so at least heat won't be a problem.

Starter fluid and a match.  I guarantee you'll get a flame. 

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Disclaimer:  Don't actually try this at home, kids.

post a pic of your furnace. (like exciter did) theres enough DIY homeowners on here to help you out.

Having trouble adding the photos, but I might be figuring something out (no, not the lighter fluid idea). This furnace uses a smart valve. It appears that the igniter/heat sensor work a bit different on these. The older ones would light up as normal (full flame), and if the heat sensor failed, it would turn off. These appear to have a very small, pilot light sized flame (before the full flame) - so maybe it can still be the heat sensor. 

you could try putting a flame under the heat sensor and see if that will trigger the sensor to open the vavle.

I am HVAC trained but not a lot of field experience. Working towards the office side. However the little bit of field work I did, I saw this a couple of times and the suggestions given other than the lighter fluid are pretty good. I did come across a couple instances that the gas company had lowered the gas pressure to the house during the warm months and then the igniter wouldn't acknowledge the amount of pressure.

 

I do recall the igniter is a cheap part and easy to change but costly for a service call. There is a few forums dedicated to DIY of this nature, this is one that's not so but you may be able to get a few more suggestions http://hvac-talk.com/vbb/ if you have any more specifics I can try to look up some suggestions.

Remove the sensor / igniter and make sure it's not broken. I had that problem two years ago. Cant find a picture of it, but every winter I had to clean it, a new dollar bill will work just like sand paper.

Thanks again all - I believe that it is that the Flame sensor needs cleaning. I was thrown at first by the Smart Valve, as it seems to use a small preliminary flame that tests the sensor (my last furnace went full flame right away). I just need to find the right tool to unscrew what I believe will free the sensor for cleaning (it is squeezed back there pretty good). I will hopefully get to it later today, but I will update people when I do.