When i turn the heat up sometimes it takes a long time for the gas furnace to start ..why?

If it has a position for natural gas/propane then it needs to be changed to the position that the gas source is either propane or natural gas..

If the gas was empty for three days, the furnace may have attempted to start numerous times causing virtually ALL residual gas in the incoming line to be drawn out. You may consider purging the gas line at the clean out cap where the gas line enters the furnace. However, it should have restarted and stayed running after just a few times at the most because as long as the line was NOT disconnected from the main tank, there should be NO air inside the line to cause flame failure.

I'd suggest asking the service company to double check the furnace manifold pressure to ensure there is not a regulator related problem.

Three times this winter (on the coldest days no less) a tiny droplet of water froze internally of the regulator right on the orifice blocking gas flow.

Flame sensor might need cleaning and check connections Also check pressure switch .

I suppose this furnace is fueled by Natural Gas?
(Or is it Propane-- Bottled gas?)

Did the Service company leave you any manual, with your new furnace?
and I would think there was a warranty, for assuring you (the customer) satisfaction, no?
Have you called the people who sold/installed it?
What do they say?

If they did leave a manual-- what does it suggest for narrowing down your possible problems?
Like: Low Fuel-- Low Voltage- Filter Changes, Fan switch problems- or ignition failure problems?

For a new furnace, someone should be right there to do a start-up for you!

Let me know what you learn--

Mack B

turn the breaker off to the furnace or the switch next to furnace and turn it back on or you have to purge the line crack the line right where it ties to the gas valve or the furnace then turn the switch off and back on

Hi, propane gas is really hard on a furnace in causing a burner or burners to carbon up. Yes, there is gas coming from this orifice, what you need to do is grasp the burner from the front, lift the rear out of the slot it sets in as you pull forward, and take the burner out. Turn it over and clean it out. It may be full off rust and some carbon. You can do this, as it may take care of the problem. We have taken on some furnaces, if your home is heating fine on the 3 burners, and remove the orifice and just plug it off. Doesn't hurt anything at all, I believe its a 1/8 or 1/4' pipe plug. I have done this many times when the temperature rise is to high on a new unit, and the only option is to shut down one burner. No harm or adjustments needed. Try cleaning the burner first and make sure the tail end sets back in its slot. If this works, great, if not, plug it off and your set. Will save on your gas bill also.
Sincerely,
Shastalaker7
A/C, Heating Contractor

It sounds like you have a possible hole in the heat exchanger. Turn the heat off and turn the fan on. If you feel any air coming back out of the heat exchanger, you have a hole. A yellow flame is not a good sign. I would even consider having a service professional come out and take a look.

Sounds as the regulator is not operating correctly (possibly the control board)

1. The sensor that tells the furnace whether the gas is lit has got build-up on it and is giving the furnace bad information.
2. The flame sensor is often a single wire or rod that sticks up in the center of the flame.
3. You can shut off the furnace and the gas and clean the sensor with some sandpaper.

If that still doesn't work, the sensor may need to be replaced.

Please rate this solution.

Try cleaning the flame sensor. It is located right besides the last burner. Looks like a thick piece of wire. Take steel wool and gently remove the carbon that has built up. Should only take 4 or 5 strokes. Let me know how it goes after that. ken