furnace question

[bobg]

   I have a Miller natural gas furnace. If i turn up the thermostat it sounds like it tries to ignite but doesn't ignite. It will do this 2 or 3 times and that is it. The blower does run but no heat. Anyone have any ideas what to check for.

[magooch]

Not to be a wisea$$, but it might be prudent to check your area for someone who is a knowledgeable technician.  It might be something as simple as a valve that isn't opening, but do you really want to monkey around with something that could detonate and possibly remove you and your house?

[JonnyReb]

  I'd start by checking the pilot and\or glowplug ignitor. If the pilot is out, or the glowplugs not heating up and glowing in the combustion chamber then it'll not fire. If you have a pilot light lit, and it won't fire, your gas valve or millivolt wiring is probably causing the trouble. If you have a pilot and can't light it, or your glow plug is working fine but no fire, then i'd check the gas supply and make sure gas is flowing. A frozen regulator is a likely culprit.  If the pilot does light, but won't stay lit, its as simple as replacing the thermocouple. Most furnace problems are something simple.  J

[bobg]

     I understand what you are saying magooch. I have no intensions of working on it. Just thought if it was something simple like the thermostat i could change that. I turned the breaker off for a while and just tried the furnace and it worked. Now have to wait and see what happens the next time it calls for heat.

[Ranger99]

mine is not a miller brand.
it has some sort of carbon monoxide
sensors that get "confused" if the wind
gusts too hard and won't allow the
burners to fire off. you can visually
see the ignitor get hot . i can let it
"rest" a few minutes and it will fire
right off. it's the gas build up clearing out
and allows the heater to fire.

[SHOOTALL]

it most likely is the hot surface ignitor , easy to check watch to see if you see an orange glow as it tries to start . If not the ignitor is broken. Now if you see the orange but it refuses to start the flame sensor most likely is dirty . Clean with sand paper or steel wool and replace when possible . It is the stainless steel probe that is in the flame as it lights , looks like a shiney #8 nail in most units. It proves flame and allowes the gas valve to remain open. The three trys are a safety . Just turn off and back on to reset. They are the simple things . Miller parts are often sold at manfactured housing outlets as that is where the bulk are used . There are other safetys that can lock it out and the module or gas valve could be bad. Also if it has an induced draft fan there is a small hole with a tube comming out of it that can get pluged with linr and dust also not allowing the gas valve to open.
 With all respect if you don't know what I'm talking about you would be wise to get a tech to come repair it as you can get hurt and cost yourself alot of money .

[SHOOTALL]

BTW don't touch the ignitor or hot surface ing. with bare hands as it will ruin them.

[bobg]

   After i turned the breaker off for a while and then back on the furnace has run 5 times now with no problems. Not sure what to do now. Maybe nothing.

[SHOOTALL]

Well over the years I have worked on a couple and did nothing but move a few wires around looking at things . Turned it back on and like your's it went to working. It may have been a poor connection or maybe a control mod. glitch that self corrected. Of course it could have been low gas pressure or several other things . I would let it run until it fails again. If you are experincing low gas pressure most likely it will happen at night when demand can be high . In some places there is moisture in the lines that freeze , here the gas company will wrap meters to keep them from freezing at night.