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Furnace is less than 15years old.Its electric pilot with gas heating.The pilot lights alright just cant get the burners to ignite at all times.Sounds like the heater is on all the time. when the burners do light the house gets up to proper temp then shuts down,won't come back on till I shut everything down for a few minutes then restart the furnace. Could tis be a thermastate problem? I have the round dial thermastate with the mercury in it. I would like to go to a pragramable one, would this help?
It is an Armstrong Ultra3 80. Model series EG7G. One other number on the booklet is 38731J092It is an Armstrong Ultra3 80. Model series EG7G. One other number on the booklet is 38731J092
The sequence of operation is just like you said except after the pilot is lit,(electric) the burners do not light.Sometimes the burners light for a second or two then go out.The sequence of operation is just like you said except after the pilot is lit,(electric) the burners do not light.Sometimes the burners light for a second or two then go out.
I cleaned off the thermocouple this morning and so far the furnace has been running fine. Cross my fingers and hope for the best. Thank you for your time and knowledge.I cleaned off the thermocouple this morning and so far the furnace has been running fine. Cross my fingers and hope for the best. Thank you for your time and knowledge.
Unfortunately I can not find any information from the numbers you provided. However, We may have a combination of problems. First make sure that the thermostat "fan" setting is in the auto position. Then describe the sequence of operation as you see it. It should be something like this: Thermostat calls for heat Then the inducer fan comes on (if applicable) Then the pilot is lit (Electronic or standing pilot) Then the gas turns on creating flame in all the burners Then a short time passes before the main blower fan begins
The shut down operation is basically the revers of the above. Please let me know.
Unfortunately I can not find any information from the numbers you provided. However, We may have a combination of problems. First make sure that the thermostat "fan" setting is in the auto position. Then describe the sequence of operation as you see it. It should be something like this: Thermostat calls for heat Then the inducer fan comes on (if applicable) Then the pilot is lit (Electronic or standing pilot) Then the gas turns on creating flame in all the burners Then a short time passes before the main blower fan begins
The shut down operation is basically the revers of the above. Please let me know.
Re: get heat for awhile then the furnace shuts down.
Great this is good information. I believe it to be one of two issues. 1) The thermocouple (rod that sticks into the flame) is dirty. You can clean this with some steel wool or light sandpaper. 2) If solution #1 does not work then I will say that we have a faulty gas valve (assuming that the gas content and pressure into the house are ok). These are usually pretty generic and can be purchased at your local Grainger (or the like) supply house. Make sure that you are familiar with all of the components involved and read the directions before you remove the old one. If you are not comfortable with this task PLEASE call a licensed technician over. Thanks and good luck!
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This can be a number of things; 1. Thermostat is not programmed properly and all your doing is rebooting it 2. Bad electric ignitor for the furnace 3. Wiring is wrong from thermostat to furnace or vice versa
This past week I changed out an old hot air furnace in a rental unit that made me question why the tenant did not go to the owner and offer to pay more rent in exchange for getting the furnace changed out sooner. If you are a renter that is paying the gas bill, then you need to think about this.
The hot air furnace was at least 60 years old. It had been coal fired furnace that was converted to gas many decades ago. The pilot light of this beast was more of a torch than a pilot light. When the thermostat called for heat the flame roared for 15 minutes before the exterior blower unit that was added when the furnace was converted to gas, started up to move air through the furnace and into the house.
As I was starting up the new unit, which took up less than 1/3 of the space of the old beast, the renter came and sat down on the basement steps looking on in amazement. How would that little thing make enough heat for the house? A few minutes later those questions were put to rest very quickly.
After starting the new furnace and burning off the oil that always smokes up the house a bit on a new startup the new little unit had the house warm as toast and was shutting down. Wow, that took less time than the old beast took to just warm up!
The renter related to me how that the old furnace cost over one hundred dollars a month just to run the pilot over the summer months. The wintertime heating bills were many times higher than that. The difference between the bills of the old unit and the bills that will be coming now will be unbelievable. A savings of 40-50% is not at all out of the question.
Now, if you are renting and are paying the bill to feed an old monster of a heating system, I suggest that you make a proposal to your landlord. Offer to pay a bit more rent in exchange for a new heating system. Not only will you decrease your gas bills enough to pay some extra rent and still come out ahead, but you will have the peace of mind that you have a safer heating system under the roof that you also live under.
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The electronic ignition system in a gas furnace is a modern development that provides more reliable performance than a standing pilot and offers energy savings through better furnace efficiency. There are two basic types of electronic ignition systems:
An intermittent pilot system uses an electronically controlled high-voltage electric spark to ignite a pilot light and subsequently the main burners when the thermostat calls for heat.
A hot surface ignition system uses an electronically controlled resistance heating element, not unlike a light bulb filament, to ignite the gas burner.
Understanding some of the basic components of a modern furnace will help you identify the type of furnace you have and narrow down the list of potential problems.
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Types of Electronic Ignition Furnaces
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Most furnaces with electronic ignition are either conventional induced draft furnaces or high-efficiency condensing furnaces.
Induced draft furnaces use a small fan to draw the combustion gasses from the combustion chamber and out of the house through the flue (chimney). This system is more reliable and safer than old conventional furnaces, which relied on a natural draft coming in from an opening at the front of the furnace. Induced draft furnaces use either an intermittent pilot (IP) or hot surface ignition (HSI) instead of a standing pilot light. The combination of electronic ignition, electronic controls, and artificially created draft improves the efficiency of induced draft furnaces over older conventional models. Condensing furnaces use two heat exchangers, where conventional furnaces use only one. After the gas is burned to heat the primary heat exchanger, the secondary heat exchanger draws heat out of the hot exhaust gasses, cooling them to the point that the water vapor in the exhaust condenses into water. The resulting flue gases are so cool they can be vented outside via a plastic (PVC) pipe, while the condensed water is run to a floor drain. Condensing furnaces use hot surface ignition (HSI).
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Troubleshooting an Intermittent Pilot (IP)
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Typically found in induced draft furnaces, an intermittent pilot ignites the burner gas with a high-voltage spark only when the thermostat calls for heat. Once the pilot is lit, and the main burner senses the pilot flame (using a flame sensing rod), the main burner ignites. The intermittent pilot flame goes out after the heating cycle and remains off until the next time the thermostat calls for heat.
The furnace gas valve for this type of furnace is identifiable with its solenoid designations: MV, PV, and PV/MV - where MV = main valve, PV = pilot valve, and PV/MV = common.
Common problems with IP ignition include:
Ignition doesn't occur, and the furnace won't go on
A spark is present, but the pilot won't light
Pilot lights, but the main burner doesn't come on
Burners ignite but turn off after a few seconds
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Troubleshooting a Hot Surface Igniter (HSI)
The hot surface igniter (HSI) is the most commonly used electronic ignition system. It works like a light bulb filament, heating up when electricity is passed through it. Most are made from silicon nitride or silicon carbide. The igniter is located in the flow of gas entering the burners.
When the thermostat calls for heat, 24 volts are sent to the electronic ignition control module, which energizes the furnace blower and other systems and sends 120 volts to the HSI. The HSI heats up to around 1,800°F to 2,500°F and glows red-hot. Then the gas valve opens, and the burner gas is ignited by the HSI. Once a proper flame is sensed by the flame sensor, the HSI turns off and stays off until the next heating cycle. In some furnaces, the HSI also serves as a flame sensor (called local sensing) instead of having a separate sensing rod in the burner flame (remote sensing).
Under normal conditions, an HSI should last for three to five years, and they eventually crack and need to be replaced. This can happen sooner if the oils from your skin get on the element through improper handling. That means: Don't touch the element with your bare hands!
HSIs usually cost between $25 and $50, and it's a good idea to keep a spare on hand, in case one goes out at night or on the weekend, when you can't easily get a new part.
Here are some of the common causes of HSI failure:
Premature failure due to improper handling (oil from skin got onto element)
Improper igniter
End of normal usage life cycle (keep a replacement on hand)
Voltage in the furnace electrical circuit is too high (over 125 VAC)
Severely dirty air filter, causing the high-temperature limit switch to cycle the furnace ignition on and off frequently
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Reading Control Board Codes
Mohd Firdaus Mohd Damanhuri/EyeEm/Getty images
Most modern furnaces with electronic ignition systems have an integrated circuit board that controls many sophisticated processes. The boards can perform self-diagnostics and provide failure codes, similar to the diagnostic computer in your car.
If a failure occurs, LED lights on the control board light up in a blinking pattern to indicate a specific failure code. The codes are listed in a chart in the owner's manual and usually on a door or access panel on the furnace. Control boards are usually located inside the blower compartment of the furnace. If the board has blinking lights, refer to the chart to decipher the code and help identify the problem area with the furnace.
Turn of the system at the thermostat. If you turn off the blower, assuming you mean at the tstat, there's no need to turn off the pilot. If blower is running and won't stop, even if turned off at tstat, turn off power by any means necessary, and pilot does not need to be turned off. A "standing pilot" is made to stay lit at all times, running or not.
Remove the cover over the burners so an inspection of the heat exchanger is a bit easier. Take an LED flashlight and a small telescoping mirror and inspect the heat exchangers front section above the burners giving special attention to the two sections of the chamber on either side of the pilot light. Many times there will be a hole in the chamber or a crack that will allow the blower that circulates the air into the duct blow out the pilot light.
If you are handy enough, consider turning off the gas and remove the ribbon burners prior to performing your inspection. The pilot assembly is probably attached to one of the burners. Lay them on the floor in the order in which they install in the furnace as some furnaces have dedicated left and right end burners and most older standing pilot furnaces have the one burner with the pilot mounting bracket.
To remove, many times you gently pull backwards towards the gas manifold while raising up on the front of the burners. Once elevated enough, the burner then slips off the brass spud (orifice) and forward and out.
The next reason the pilot can go out is because the safety 'holding' coil in the gas valve is defective. Its responsibility is to hold open electrically a safety circuit proving the pilot gas is burning so that main gas can flow. The thermocouple generates just enough electricity to hold the safety coil open. Coil bad = pilot out.
If your furnace is over 25 years old, there is a good chance there is a hole or crack.
How many degrees before it reaches desired temp, does it shut off? A thermostat is designed to shut the furnace off a couple/ few degrees before it reaches set temp. It has what is called a heat anticipater, which shuts the burner down, and lets the blower use the remaining heat from the heat exchanger to bring it up to desired temp making it more efficient. If it is more than a few degrees, replace the thermostat. You can jump out the red and white wires to confirm the faulty thermostat. If by doing this, the furnace never shuts down, until you separate the red and white wires. That confirms a faulty thermostat. Hope this helps someone.
A thermocouple is a bi-metallic junction that when heated gives an small electric output. The tip of it sits where the pilot light is ( and it is a copper tube going to the gas valve) and the pilot light heats it up. It creates electricity after it heats up (which is why you have to hold the pilot light knob down when lighting) and opens the gas valve to keep pilot light lit after you let the pilot knob go back up. When it stays lit without having to hold it down, (make sure the thermostat is set low so it doesn't light the burner while you have your hand down there) then you turn the pilot knob to on. It should stay on and you can set the furnace to heat and raise the temperature where you want.
It sounds like you're describing one of two things. The hot surface ignitor in a gas-fired furnace, or the resistive heat strips in an electric furnace.
The hot surface ignitor in a gas-fired furnace lights the burners. This ignitor in modern furnaces serves the same purpose as the standing pilot flame did in older furnaces. It provides the required heat to ignite the gas at the burners. Without an ignition source, a gas-fired furnace cannot provide heat. When the ignitor is activated it will glow bright orange or yellow.
The resistive heat strips in an electric furnace actually provide the heat to a home or building. When the furnace turns on, the heat strips are activated and usually glow orange when they reach peak temperature. In almost all cases, the heat strips are not easily seen or accessed without removing covers or panels inside the furnace.
I'm a little confused by your terminology. You are saying you have a pilot lite and electric heat strips? Are you possibly meaning burners? Is the heater running for 2 hours straight without shutting off? how cold is it there? Lastly what temperature do you have the thermostat set at and how close does it get to the temp. before it shuts off?
It is an Armstrong Ultra3 80. Model series EG7G. One other number on the booklet is 38731J092
The sequence of operation is just like you said except after the pilot is lit,(electric) the burners do not light.Sometimes the burners light for a second or two then go out.
I cleaned off the thermocouple this morning and so far the furnace has been running fine. Cross my fingers and hope for the best. Thank you for your time and knowledge.
Unfortunately I can not find any information from the numbers you provided. However, We may have a combination of problems. First make sure that the thermostat "fan" setting is in the auto position. Then describe the sequence of operation as you see it. It should be something like this:
Thermostat calls for heat
Then the inducer fan comes on (if applicable)
Then the pilot is lit (Electronic or standing pilot)
Then the gas turns on creating flame in all the burners
Then a short time passes before the main blower fan begins
The shut down operation is basically the revers of the above. Please let me know.
Can you provide us with the furnace brand and model number?
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