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Furnace burners wait too long to come on

Furnace wait too long to come on and then comes on with big booh and after 5-10 minutes burners and pilot goes off together. I already change the thermocoupler. any advise? Mitchell Manuf. Model 75-AGCF s/n- f1-113

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Re: Furnace burners wait too long to come on

Sounds like the burners need to be removed from the furnace and cleaned thoroughlyto help with gas distribution if these are in-shot burners they look sort of like an air plane, they have a cross over tube on each side of each burner and if that is rusted up the gas will not distribute evenly from one burner to the next if the pilot and burners go off at the same time then it sounds like you may have some flame blow back maybe due to soot build up in the heat exchanger. Overall sounds like your furnace could use a good servicing

Posted on Oct 16, 2007

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My heil furnance comes on but no hot air or air at all

see this causes and fix it. God bless you
o light the pilot on a standing-pilot (always on) ignition system, follow the lighting instructions located near the control. Otherwise, try these steps: Light the pilot:
  1. gasfurnace1.jpg Press and hold the pilot control knob to start the pilot. Set the control knob to the pilot position. Hold a long match under the pilot gas port.
  2. Press the control knob; the pilot should light. Hold the control knob down until the flame is burning brightly (about 30 seconds). Release pressure on the knob, and turn it to the on position.
  3. If the pilot goes out when you release the control knob, try relighting, holding the control knob down longer. If the pilot again goes out, check the thermocouple (below).
Adjust the pilot:
  1. Remove any cap covering the pilot adjusting screw on a combination control.
  2. Turn the adjusting screw counterclockwise to increase the flame or clockwise to decrease it. It is correctly adjusted when the flame envelops the thermocouple bulb by 1/2 inch and appears dark blue with a small yellow tip.
Test and replace a thermocouple:
  1. Hold the control knob to pilot and light the pilot as above.
  2. Unscrew the thermocouple fitting with an open-ended wrench.
  3. Set a multimeter to the DVC (lowest voltage) scale.
  4. Clip one multimeter lead to the end of the thermocouple tube nearest the pilot and the other lead to the fitting on the other end of the tube.
  5. If the multimeter shows a reading besides zero, the thermocouple is functioning. Replace the thermocouple tube.
  6. If there is no reading, you will need to clean or replace the thermocouple following steps 7 through 11.
  7. Release the control knob and shut off the main gas valve on the gas-supply pipe that leads into the burner. Shut off power to the burner at the electrical service panel .
  8. Remove the thermocouple from its mounting bracket.
  9. Wipe the combination control clean and install a new thermocouple, tightening it by hand, then give it a one-quarter turn with a wrench.
  10. Insert the thermocouple into the pilot bracket, being careful to not crimp the tubing.
  11. Turn on power to the furnace and relight the pilot (above).
Adjust an adjustable burner air shutter:
  1. Set the thermostat to its highest setting to keep the burner running. Once the furnace has heated up, remove the burner access panel and loosen the locking screw.
  2. Open the shutter by turning it to the right until the blue base of the flame appears to lift slightly from the burner port surface. Then close the shutter until the flame reseats itself on the surface.
Clean removable burner tubes and ports:
  1. Shut off gas and power to the furnace.
  2. Unscrew or loosen and remove the tubes from the supporting bracket.
  3. Carefully clean the tubes with a brush or vacuum, making sure not to damage the burner ports.
  4. Use a stiff wire to clear any debris from clogged ports.

Oct 08, 2012 | Honeywell Icp Heil Tempstar Furnace Spark...

1 Answer

My screen is out on my chimney flute, a bird was trapped inside and worked it's way to the furnace and was killed there. The bird has been removed, now the furnace is not producing airflow throughout the...

The pilot is iside the burner compartment of the furnace. Remove the cover and follow the 1/8" tubing to an orifice. This is where you light the pilot. the gas valve must also be turned off for a couple of minutes before trying to light the pilot. After a few minutes, turn the valve to pilot and light the pilot. Hold it for 30 seconds and then turn the valve to "ON"

Jan 26, 2011 | Air Conditioners

1 Answer

I have an amana furnace and it will not kick on. When the switch is turned on the furnace will try to run but won't warm up and blow. Does it have a pilot light?? or a reset button??

Try this----turn furnace off at stat and unplug furnace for 10 minutes. Plug it back in, the combustion and blower motor may both kick on for 2 minutes or so or not. Turn t-stat to heat and turn up stat to highest setting. Hurry out to furnace and you should hear the combustion motor(little motor piped to flue) kick on, then wait for a "click" next you should see a glow from the igniton element, then another click, next will be the gas valve opening. If no ignition, it will try 3 times and then lock ur *** out, and just turn on the blower just as a precaution. If you dont see the glow plug glowing after the first click, replace the $20 glow plug and you should be good to go. The glow plugs crack, and this is what breaks the connection. If you gas valve has a knob, and says pilot----turn the valve to pilot, push down on the knob, light the pilot and hold down knob for 2 minutes to heat up flame sensor. Make sure the t-stat is all the way down or off. After 2 minutes of holding pilot knob down, let go and your pilot should be still lit, if it is, then turn gas valve to ON and then turn t-stat up to kick on furnace. If ur pilot doesn't stay lit, get a new thermal couple and replace it-$12 bucks. Good luck and let me know how it went.

Nov 06, 2010 | Air Conditioners

1 Answer

Im trying to figure out how to light my neighbors 7900 series gas furnace. Followed instructions pressing pilet light etc. Just cant figure where to ignite inside furnace door.

Hi, Just follow the pilot light tube back, the aluminum tube, back under to where it stops at the pilot burner. You may need to open the door to reach back there or you may have that piece of metal that you put the match in to reach back far enough to light it. Just turn the knob to pilot, and hold it down and you should be able to hear and smell the gas. Light the match and stick it along side of the pilot tube at the very end and it will light as long as you hold the knob down. After it lights hold it for about another minute and release it slowly. It should stay light. If not wait 5 minutes and try again. Very easy to do when you follow the tube that supplies gas back to the pilot, that's where you stick the match or lighter. Look back there with a good strong light and you can see where the tube stops. This is where the gas comes out. Please let me no, and don't forget to rate me as I know you will be kind. You will find it. If you can't get it, you can call out your local gas company and they will light it for free of charge, no cost to you.
A/C, Heating Contractor

Sep 18, 2010 | Coleman Air Conditioners

1 Answer

Carrier furnace, pilot does not light, fans run for a couple minutes and then flashes code 31

On a call for heat, the 24 volt thermostat sends a signal to the control module. The control module will indicate a call for heat with a light on the control either blinking or remain solid depending upon model. The inducer (exhaust) blower will purge all gasses from the furnace and pressurize a pressure switch. Once the pressure switch tells the module to continue, the electronic ignition will energize and send 120 volts to the igniter. The igniter will glow and you will be able to see it if viewed thru the small inspection port. Once the igniter gets hot enough, it sends a signal to the module opening up the gas valve (24 volts). Either a pilot will come on or the burner tube will ignite then spread the flame to all burners. Lastly a safety sensor will be looking for a certain temperature within a few seconds and the furnace will continue to operate and the room air blower will turn on in a minute or two.

What could go wrong? The unit will not run if there is no signal from the thermostat (bad thermostat or broken wire), the control module does not sense a signal from the thermostat (bad control), the inducer does not energize (bad motor), the pressure switch does not close (blocked vent piping, bad switch, plugged condensate hose), the igniter does not energize (bad control, bad igniter), the gas valve does not open or there is no gas (bad gas valve, broken wire, no gas), the pilot does not light (dirty pilot), the burner does not light (bad burner, plugged orifice, not enough combustion air), the flame does not spread to each burner (bad flame spreader, dirty flame spreader, more bad burners), the flame safety sensor does not detect flame (dirty or bad flame spreader, bad flame sensor, broken wire, bad control), or the room air blower does not energize (bad fan motor, bad control).

Nov 28, 2009 | Carrier 38CKC042 Air Conditioner

1 Answer

Rheem gas furnace pilot lights, but no burners or fan

If the burners do not fully ignite, the sensor will shut the furnace down. The lack of sufficient burner flame is a gas valve or gas pressure problem within the valve.
Replacing the gas valve with the original one may get you going. I surely suggest a professional service company for safety reasons and a thorough inspection. A 20 year old furnace is past it's normal life span.

Jan 06, 2009 | Air Conditioners

1 Answer

Pilot ligting instructions

many of the newer furnaces don't have a standing pilot. look to see if you have a gas valve with a knob on top that says off pilot and on. look to see if a tube the size of a pencil comes out of the valve and goes down by one of the burners, look to see if there is a little gold piece of metal tubing protruding down to the opening of the larger tube . that is where you place the match. i prefer to use a grill lighter. safer and positive flame. turn knob to off wait 5 minutes for any gas to disipate. be sure your incoming gas valves are all open . usually at the meter and one at the furnace. usually the handle is in line with the pipe when open. from the off position, turn the knob on the furnace gas valve to pilot position and push down on it as you turn. this lets gas flow to the pilot tube by the burner where you have you flame starter lit and waiting. once pilot lights hold down on button for 3 minutes or less. longer is better to be sure the thermocouple senses flame . then gently release the downward pressure and the pilot should stay lit and you gently turn knob to on. if pilot goes out you may have a bad thermocouple. be especially careful if its lp or propane as that gas does not disipate like natural gas and can virtually lay on the floor till ignited. also consider having the heat exchanger checked by a pro with a carbon monoxide detector. they do crack after a few years and can be deadly when they do. good luck

Nov 13, 2008 | Carrier XHB123D X/Y Series Heat/Cool Air...

1 Answer

I have a Trane gas furnace BLU080E, pilot light remain on set the thermostat above room temperature fan start runing after few minutes but main burners remain off and have 24 volt on gas valve.

almost a classic sign of a bad gas valve. pilot is lit so gas is available. FAN COMES ON AND 24 VOLTS TO gas valve so there is a call for heat . gas valve doesn't open so it looks like its bad.

Nov 10, 2008 | Air Conditioners

1 Answer

Carrier Weathermaker SX model 58SX060-CC Blower runs all the time

Remove all power from the furnace, it is likely the brain in the furnace is need of being reset, from the battery replacement, why did you change the battery, was there an indicator telling you to change it?

Many times just removing all the power to the furnace will do the trick with a reset, if not let me know and we will go from there, but it sounds like the main brain is confused or bad, more likely confused, so try the power removed first.

Than let me know

Oct 22, 2008 | Carrier XHB123D X/Y Series Heat/Cool Air...

4 Answers

Carrier weathermaker sx 58 furnace

I have serviced these furnaces for 20 years and I can tell you most of these models did not have diagnostic lite on them. (although some did, especially if the control board has been replaced) The problem is most likely a bad 3 wire pilot. This will cause exactly what you describe. 2 things to consider though. 1, If you were to replace the pilot don't get a cheaper knockoff. In my experience these do not last long at all. Get the right one from a carrier dealer. It will cost more but be much more reliable. 2 What is the condition of the secondary heat exchanger? Most if not all of the sx series had issues with the secondary heat exchangers rotting out and leaking. If the furnace is out of warranty you would be much better replacing the furnace as the cost of replacing the secondary heat exchanger will probably be almost the same as a new furnace. ( those babies are EXPENSIVE!)

Dec 17, 2007 | Air Conditioners

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