Strange start of the season furnace startup problem

[Hybyd2]

Last year when I turned on our gas furnace for the first time ... I went to the attic and found the igniter buzzing away and to state the obvious - the burner was not doing a thing. Came down and turned the thermostat off. Igniter stopped. Waited a little while and moved the thermostat again - repeat performance from the igniter. Once again turned the thermostat off. I called a professional who was recommended by friends. He showed up - I tried demoing the problem. I say "tried" because as soon as I moved the thermostat the furnace fired. Well, since he was around he checked the furnace and said it all looked fine, and I had no problems all last winter.

This year I went through a similar sequence this past weekend. Three times it did not start (the igniter buzzing away). The fourth time, I turned on the fan (for no logical reason) and then moved the thermostat and the burners fired. I've moved the fan back to auto and the heat has been fine for about three or four cool days when it came on. The weather has warmed up now.

This is a 20-year old Carrier gas furnace (58 series). Should I get another professional to look at it? The professional I got last time was well recommended and he didn't recommend doing anything last year. I do realize that it's advisable to have a yearly checkup - I'm curious if a different professional would have had a different diagnosis. I certainly don't intend to perform any repairs myself though I'd appreciate theories on what could be causing this behavior.

Thank you for taking the time to read this.

Henry

[jhill]

I had a problem simular to yours with a garage heater. My main heater is in the basement, and the gas -line comes in to it first, then runs up to this garage heater. During the summer, I would shut off the piolet light. When it got cold enuf, I would go out and try to light the piolet but it would not light for quite a while. I had to hold down the button for up to five minutes before gas came out. The explaination I got from the company is that the gas around here contains trace amounts of helium and other lighter-than-methane gases that would fill up the pipe running from the basement, but does not burn. It took five minutes to blead out this stuff before the methane reached the piolet.

[willshak]

I have a 20' x 20' 4 Seasons room that is heated by a unvented propane fireplace (CO/Smoke detector installed in room). We shut it off last spring. The pilot light was turned off, but the gas line shutoff valve was left in the open position all summer. Last week we turned it on, and it took a few minutes for it to light for the same reason, no propane gas in the end of the line by the fireplace. There is a T fitting in the line that also feeds the propane gas clothes dryer just inside the wall from the sun room, so I figure that the dryer just siphoned off the gas from the T fitting to the fireplace.