Furnace Burner Shuts Off When Blower Starts

then eventualy it goes out and the fan keeps blowing cold air until you reset the thermastat or turn the power off then on. It is usually located near where the flames shoot out of the burners. the furnace seems to be ok other than no gas flow. Check the shut off valve outdoors or starting another gas burning appliance to see if it works. Check the burners. TO SEE A COMPLETE PARTS NOMENCLATURE FROM THE MANUFACTURER OF THE PARTS FOUND ABOVE CLICK HERE Lau blower parts nomenclature. Usually, the fan limit switch will turn the burner off if the temperature gets too high. We will give you the best service at the best reasonable prices. Under normal conditions, when the furnace is running, the air coming into blower from the house (return air) is generally 60 to 68 degrees F. Let's say that your furnace's burners come on but the blower motor is bad and will not start. i call for heat and the furnace lights fine. In the event there's a call for heating, the blower shuts off, the board surveys the state in which the safeties are in, if that checks out the inducer then starts and proves, then after a short delay the hot surface ignitor is energized for a period, gas valve opens and proves flame, then the blower starts 45 seconds(+/-) after burner proof. Ordinarily, in a forced hot air system, the furnace blower will continue to operate for another minute or two, forcing the last of the heated air from the plenum into the home, and then shuts down. 5) After a sufficient amount of time for the heat exchanger to cool down (some furnaces use. If the pressure switch is closed, where power can pass through, the IFC will stop the process and try again. I got under the house and watched the furnace "cycle". The technicians at Furnace Repair Pros specialize in quality HVAC repair, maintenance and installations. That drop in pressure causes your sheet metal ducts to suck in, and they give off that loud noise. Replace thermostat batteries. Blower won't stop running : 1. I used to have to tap on the cover of the switch mechanism to get it to break loose. Will try three times and then shuts down. What to Do When Your Furnace Blows Cold Air. Furnace kicks on. It's possible that the part is not bad, but just needs to be cleaned. So take that into consideration before you attempt any of these troubleshooting steps. the furnace seems to be ok other than no gas flow. The sequence how a gas furnace works normally is : thermostat calls for heat, blower comes on for a few seconds and is shut off, gas valve opens and an igniter lites up and burners come on giving. It just doesn't stay on. The pilot is lit, the burner ignites as it should but the blower will not shut off once the cycle is complete. Your blower should run constantly until the heating cycle ends. After 4 or 5 seconds the flame would shut off and after another 15-20 seconds (with blower still on) the flame sequence would start and light again. Wired wrong Correct wiring Faulty relay Replace relay BLOWER VIBRATES OR IS NOISY. Clean or replace filter. If the cad cell cannot prove the burner flame, it opens the circuit to the burner, which shuts off the burner motor and the ignition trans- former. I have a suburban model sf-42f, the furnace lights up normally and heats for about 5-7 minutes then the heat starts going away until cold, but the blower continues and doesn't shut down until i turn it off. If the sensor has corrosion on it, sanding it might work, though replacing it is a longer-lasting fix. The technician suspects a faulty. My Furnace Starts Then Stops If your furnace runs for a few minutes and then stops, it can be really annoying and get really cold. A furnace that starts then stops is a common issue also known as short cycling. Not only does this decrease your comfort, it can damage your furnace. Remove the blower compartment panel by lifting up. When the stat loses power, (most Residential Carrier / Bryant / Payne equipment). The function of the cad cell is to prove (detect and verify) the burner flame at the start of the heating cycle. The burner and pilot all seems to work. Then the problem isn't a lack of power. If the air flow is blocked and the furnace continues to become warmer and warmer, as the heat its making is not being taken away by the blower fan a 2nd switch comes into play and turns off the oil or the gas part of the heating side of the furnace so it does not over heat. This will happen two or three times and then finally stay off like it normally would. If the burners are turned off, your furnace will not have a heat source and cold air will blow out of your registers. Short Cycling is the process in which the following occurs: Thermostat calls for heat; Gas furnace turns on and runs; Within just a few minutes (usually less than 5 minutes) the furnace turns back off. Nobody wants a furnace that blows cold air, especially if the temperature outside is really chilly. it it makes the noise its the blower. When the thermostat is satisfied, all the burners will shut off and, after the. I noticed that the room temperature was dropping and the blower was blowing cold air. Forced air heating is probably the type of central heating most commonly installed in North America. The noise stops as soon as the thermostat upstairs reaches the temp it's set for and the burners shut off. If the gas burners now shut off,. Re: Furnace blower comes on before ignition Ok, thanks for the replies. Furnace Inspections: Why and How This Appointment Helps Your Heating System. 2) Burner starts 3) Blower starts after 45 seconds 4) Burner shuts down after call for heat is satisfied 5) Blower stops according to adjusted (FAN OFF) Dip switch selection ST9103 Cooling Sequence 1) Thermostat calls for cooling 2) Blower starts immediately. time during non-heating season, follow furnace shut down procedure. If you suspect a hole shut down your furnace immediately until you can test it. The heated air then cools down in your home's various rooms and returns to the furnace through return air grills and ductwork. My gas burner will usually shut off before the blower, but a couple of times in the last three days it has not. The inducer (exhaust) blower starts closing contacts in the pressure switch (small disc shaped thing), the igniter glows orange (seen thru a small window high up on furnace front), gas valve opens allowing main burner to light, flame travels to all other burners, flame rod senses flame within a few seconds and keeps gas on. Then when the unit shuts the fuel off, as the heat is extracted from the. Obstructed return air intake. One sign that your furnace may need some attention is that your furnace fails to turn off and continues to run, even when the temperature reaches the set temp on the thermostat. It may have been closed during the summer, when the furnace or boiler was not needed, as a safety precaution. Note that the temperature has not reached the setpoint. Starts again, fires, stays lit for a few seconds and then shuts off. Then the problem isn't a lack of power. It is not normal for a heating cycle to be so fast, and short cycling can cause damage to the furnace. Kevin All furnaces start up cold tell the blower starts going full speed and it shuts down the burners at temp and then the furnace gets down to 160 and shuts of then blower. If you own a gas furnace, keeping the unit in top running condition is important for the safety of the home's occupants. If it detects that the burners are not lit, it will shut them off. When a Flame Sensor is malfunctioning, it makes the furnace cycle on and off repeatedly. Talked to a tech at Beacon Morris, he gave me a few things to check and then determined I had a bad control board. Then the main blower starts working and the whole thing stays on for 2-3 minutes. If motor and blower have oil ports, lubricate. Furnace Service In Bonlee. If the pressure switch is closed, where power can pass through, the IFC will stop the process and try again. I have to go upstairs to the hallway and unplug the furnace from the outlet to shut off the fan. Probably the first thing that can happen that will prevent the furnace from starting is the failure of the draft motor. Check the wiring to your furnace's thermostat. Is this an indication the motor will be going out soon? There's also a run capacitor mounted on the side of the blower housing, can the sound have anything to do. Start the burner and after a few moments of operation shut off the burner. Once lit the flame is sustained by air supplied by the blower. A lockout code will be displayed on the IFC. Correct as required. The two common reasons for inefficient cut-off on fuel pumps are a defective check valve ball in the pump, or poor connectors allowing air into the piping system. The heat exchanger is designed to be heated by the burner flames while the furnace blower moves room air across the outside of it. What to Do When Your Furnace Blows Cold Air. Clean or replace filter. Lennox Gas Furnace that turns on and shuts off in minutes The unit will turn on and run fine for a few minutes then shut off. The inducer (exhaust) blower starts closing contacts in the pressure switch (small disc shaped thing), the igniter glows orange (seen thru a small window high up on furnace front), gas valve opens allowing main burner to light, flame travels to all other burners, flame rod senses flame within a few seconds and keeps gas on. A constantly running furnace that doesn't shut off can be a sign of a needed repair. Published May 24, 2016 By: Gary Sprague. To stop the furnace, first try turning down the thermostat. A furnace that keeps shutting down early. Like any other kind of central heating system, thermostats are used to control forced air heating systems. starts and stops the furnace to maintain the desired room On Auto, the circulating air blower will cycle on/off with the furnace but if switched to ON it will run continuously regardless of whether or not heating or cooling is being provided. When proper temperature is reached the burner will cut off, blower will continue to run for a short time. A faulty thermostat that regulates temperature also causes the furnace to become loud and noisy or when the blower is set at a high speed. That drop in pressure causes your sheet metal ducts to suck in, and they give off that loud noise. Could be that the air filter is so dirty its causing the sheetmetal to colaps when the blower starts and stops. Give us a call! Call us now to get your heater repaired. Short cycle time: A few seconds after the burner fires. A defective control board causes the blower to run continuously. Motor and/or blower needs lubrication. Original problemfurnace blower was running continuously, while maintaining temp. Can it be the switch above the burners or the switch that is by the blower?. Aboute 30 seconds later, It tries again, and does this for three or four timesand eventually stays on. Also, try checking the motor and blower for clogs or the need for lubrication, as this might be another cause. a blower motor and a combustion motor. What happens is that the thermostatic spring gets old, corroded and starts to stick. By Steve Savage Mobility RV Service When winter arrives, most service calls I get are for furnace repair. Observe what happens in the burner area. The furnace tries a total of 3 times, then if flame is not established goes into hard lockout. Under normal conditions, when the furnace is running, the air coming into blower from the house (return air) is generally 60 to 68 degrees F. In our new-to-us 2003 Fleetwood Sea Pine, the furnace stopped working. Lower the thermostat in order to stop the furnace. The blower motor can become dirty or lose power, and when it does, your furnace switches itself off. furnace starts and then gas shuts off. Though it continues to recycle. Furnace under fired. Replace thermostat batteries. BLOWER DOES NOT BLOW – The burners light, but after about 2 minutes they go out again. Frequency of start-ups is not the same as short-cycling, which is actually characterized by how long the furnace runs for when it does turn on. So here is the issue. Otherwise, the “always on” option will keep the fan running at all times, including when the burner in the furnace is not active. Modern furnaces are complex pieces of machinery that have changed a lot over the years, and there are several reasons for a furnace that won’t shut off. Problem: furnace keeps shutting off burners after a few seconds!! Solution: sand down flame sensor! Troubleshoot the oil furnace part 3. Bearings & Shafts Blower Wheels Burners Home > Relays > Timers > Relays - Furnace Blower Relays. I tested the fan limit switch and all other limits and they all check out ok. Furnace Short Cycles. Once the home's temperature aligns with the thermostat setting, the furnace shuts off. Does IBM start on heat speed 20 seconds after burners light? Does main burner remain lit until heat call ends? Does thermostat maintain reasonable room temperature near setpoint? Set thermostat to off position (W to C = ØV) Does gas valve shut off immediately? Does IDM shut off after ten second post-purge? Does IBM shut off after a max. If your furnace turns on for a few seconds and shuts off, or doesn’t turn on at all: Check furnace switch. my rheem oil furnace blower is giving me trouble. Aboute 30 seconds later, It tries again, and does this for three or four timesand eventually stays on. It's normal for burner to cycle on and off. It just doesn't stay on. The furnace starts to heat the home, but turns off again quickly after only a short amount of time has passed. Troubleshooting the RV Furnace. Set a voltmeter to the X1 setting. Dirty Burners. The burner shuts off after about two minutes, even though the teperature does not reach the upper limit - the temperature stays just above the middle trigger that turns on the fan. The thermostat is not set to Heat or a high enough temperature. Start by turning the furnace off, turn your thermostat to “fan only,” and wait a few minutes. The furnace blower will not come on after the burners have completed there cycle. It may sounds like it's coming from the heat exchanger area and not the blower, then it could be a new filter you put in is too thick and there's not enough air flow so the motor is working harder, and vibrates due to the higher. After ruling out all of the 'simple' problems above, the most likely cause of a furnace not blowing air is a problem with the blower fan itself which, if you remember, is the fan that circulates your house's air over the heated coils. It immediately starts back up and goes through the whole process about a dozen times until it finally turns on completely and heats the house. If the blower shuts off at the same time as the burners, you would have serious heat damage to the furnace. Ensure that the shut-off valve is in the open position. Kevin All furnaces start up cold tell the blower starts going full speed and it shuts down the burners at temp and then the furnace gets down to 160 and shuts of then blower. To remove bottom-mounted or side mounted filter (s) on all furnaces, push the looped end of the filter retainer rod in, and then move the retainer rod away from the filter. A furnace that keeps shutting down early. Note: I am not a professional. Dirty Burners. The reason cold air will continue to blow while the furnace is on and the thermostat is set correctly is because the fan assumes that heat is being generated by the furnace even if the burner is not running. Many standard heaters are less efficient than two-stage models because of the type of burner they use. With the front panel off the furnace will run thru full cycle but only runs about 5 min since it is under the thermostat. Any thoughts would be appreciated. Forced air heating is probably the type of central heating most commonly installed in North America. The boiler furnace must be inspected and repurged before the next attempt to light. In normal operation, your furnace blower fan should come on 1. - Duration: 8:35. Do not use this furnace if any part has been under. When the stat loses power, (most Residential Carrier / Bryant / Payne equipment). I swapped the thermostat. If the blower shuts off at the same time as the burners, you would have serious heat damage to the furnace. Under normal conditions, when the furnace is running, the air coming into blower from the house (return air) is generally 60 to 68 degrees F. I seem to have no control from the wall thermostat. If the pressure switch is closed, where power can pass through, the IFC will stop the process and try again. It does not shut off the fan (the blower motor) until it has cooled. First the burner will shut off followed by the blower. Why Does My Furnace Make a Loud Noise When It Turns Off? If you are noticing a loud noise coming from your furnace when it turns off it could be something very simple. Some common RV furnace or heater problems can be solved with basic troubleshooting and simple repairs. Without the fan limit control your furnace could over heat and cause a fire! The fan limit control shuts the gas burners down so the furnace will not over heat and cause a fire. Mike T 2005 Winnebago Voyage 33V, Workhorse W20, with '06 CR-V in tow, SMI 4 wire Braking system, Blue Ox Underskirt, Pressure Pro. Furnace shuts down- Because your furnace has to run longer to heat your home, the heat exchanger overheats, causing the furnace to automatically shut down. when the furnace thermastat is turned on the furnace lights and runs until it reaches temp. Remove the 12 screws securing the vestibule panel to the furnace casing. Problem: furnace keeps shutting off burners after a few seconds!! Solution: sand down flame sensor! Troubleshoot the oil furnace part 3. Some common RV furnace or heater problems can be solved with basic troubleshooting and simple repairs. If your furnace continues to click without ever turning on, you may have loose wiring or a leaking gas valve. Reset thermostat from ON to AUTO. Note: If your thermostat fan is set to ON, your furnace isn't actually running non-stop—just the blower fan is. When the temperature set- ting on your thermostat is reached, the gas valve closes, the main burners are turned off, and the blower continues to run until the remain- ing warm air in the system is distributed. 1 - Set the thermostat to the lowest setting. If you furnace starts to click, the blower turns on, and then back off again, you could have a problem with your flame sensor. the gas valve shuts, burners go out, and the intake blower cuts out. If not, adjust the pressure. Fault Code 31 HIGH-PRESSURE SWITCH FAULT—This fault can occur under the scenarios shown below, keep in mind that whenever furnace control board shuts unit down, gas shuts off immediately, inducer continues running for 15 sec, and if blower is running, it remains running at low-heat speed or reduces to low-heat speed for selected off delay. On this furnace, the problem is the flame sensor it develops a thin coating of clear or whitish deposits that insulate the sensor from the flame, so the ignition control module doesn't receive the signal that the flame is actually lit. The blower assembly will continue (normally) until the plenum has cooled down. From the top-of-the-line Evolution ® 987M through the solidly build Legacy™ line furnaces, Bryant ® furnaces perform. The gas valve causes the heating cycle to stop. Correct as required. Once in a while furnace will keep running. York Furnace Repair (part #S1-02435647000) - YouTube This video provides step-by-step repair instructions for replacing the blower motor on a York furnace. If that doesn’t work, then turn the furnace OFF at the thermostat. To turn you oil furnace on for the winter, you can either flip your emergency shut-off switch back to "On" or follow these steps: Ensure your oil tank is full. The fan limit control is an important safety device. A defective control board causes the blower to run continuously. 2 days ago, furnace air intake ducts start emitting a "burning odor" when the unit is running. Many standard heaters are less efficient than two-stage models because of the type of burner they use. second fan cycle after furnace shuts off. Burns for several minutes but then flames out and tries to relight then goes into lockout and shuts down. One of the most common issues with a furnace blower fan is the inability to start. Note: I am not a professional. Reset thermostat from ON to AUTO. To remove bottom-mounted or side mounted filter (s) on all furnaces, push the looped end of the filter retainer rod in, and then move the retainer rod away from the filter. Blower runs for 15-30 seconds then burner will fire up. It may sounds like it's coming from the heat exchanger area and not the blower, then it could be a new filter you put in is too thick and there's not enough air flow so the motor is working harder, and vibrates due to the higher. About 3 seconds after the gas ignites,. Then the furnace starts and operates just as before. Digital and programmable thermostats have built in heating and cooling anticipators which automatically set themselves without any manual adjustments. Everytime the thermostat activates, the furnace turns on and heats up. If the high limit switch goes bad, the furnace won't shut down and the heat exchanger will crack. A defective control board causes the blower to run continuously. Forced air heating is probably the type of central heating most commonly installed in North America. It may look something like this:. The Furnace Won't Start  First of all, Richter advises, press the reset button, which manually starts the furnace. The sequence how a gas furnace works normally is : thermostat calls for heat, blower comes on for a few seconds and is shut off, gas valve opens and an igniter lites up and burners come on giving. Hi,I have an older Bryant 75000 BTU Natural Gas furnace built in 1986 with a HH84AA 011 board. If the air flow is blocked and the furnace continues to become warmer and warmer, as the heat its making is not being taken away by the blower fan a 2nd switch comes into play and turns off the oil or the gas part of the heating side of the furnace so it does not over heat. Check the wiring to your furnace's thermostat. from a direct source. Note: If your thermostat fan is set to ON, your furnace isn’t actually running non-stop—just the blower fan is. i call for heat and the furnace lights fine. Activate the furnace blower by setting your thermostat fan switch to the "On Turn the control dial setting to the "Off" position. This switch shuts the furnace off for servicing. It immediately starts back up and goes through the whole process about a dozen times until it finally turns on completely and heats the house. Once lit the flame is sustained by air supplied by the blower. It's possible that the part is not bad, but just needs to be cleaned. My gas furnace blower runs for one minute then shuts off but the burners stay on My gas furnace ignites normally, blower starts, runs for 1 minute, then blower shuts down, but flame stays lit. GAS, OIL OR GAS/OIL BURNER GENERAL 1. Hi,I have an older Bryant 75000 BTU Natural Gas furnace built in 1986 with a HH84AA 011 board. It continues to this anywhere from 5 to 20 times before completely shuting down. If your furnace shuts off when you turn the thermostat to off, a possible cause is a malfunctioning thermostat and replacing it should fix your problem. What to Do When Your Furnace Blows Cold Air. I have a suburban model sf-42f, the furnace lights up normally and heats for about 5-7 minutes then the heat starts going away until cold, but the blower continues and doesn't shut down until i turn it off. There is a red LED light inside the furnace that flashes one time. The limit switch is a safety device that protects the furnace from over heating. When the furnace ignites the turbulence makes the pilot waver and the burner shuts down. If the air flow is blocked and the furnace continues to become warmer and warmer, as the heat its making is not being taken away by the blower fan a 2nd switch comes into play and turns off the oil or the gas part of the heating side of the furnace so it does not over heat. Start by turning the furnace off, turn your thermostat to "fan only," and wait a few minutes. However that becomes short lived. Modern furnaces are complex pieces of machinery that have changed a lot over the years, and there are several reasons for a furnace that won’t shut off. The noise may be described as a loud boom or bang and can be disconcerting when you hear it, especially for the first time. A flame sensor can get dirty over time, especially if you run your system with a dirty air filter, which can cause it to turn the burners off prematurely. CHECK OUT: Angie's List Guide to Home Heating Systems. The blower is located between the return ductwork and the furnace. When your furnace isn’t actually heating, though, your furnace blower shouldn’t be running at all. The inducer motor starts 30-60 seconds before the gas fires. When there is a demand for hot water, everything starts up normally, but the burner goes out (can hear the solenoid click shutting it down) before the water is up to temp (the blower continues to run and the pilot is lit). Control circuit has an open control contact. Worked the night before. I have a 2 year old freedom 80 furnace. Furnace shuts off before it reaches the desired temperature. about a minute latter the blower starts. CASE #1 (Common) Furnace BURNER Short-Cycling On and Off During a Call for Heat - High Limit Rocking. The drum the lint does get past the basket and then accumulates in the vent and also the. According to the chart in the furnace, it says “Lockout Check Furnace”. 2) Burner starts 3) Blower starts after 45 seconds 4) Burner shuts down after call for heat is satisfied 5) Blower stops according to adjusted (FAN OFF) Dip switch selection ST9103 Cooling Sequence 1) Thermostat calls for cooling 2) Blower starts immediately. If the air flow is blocked and the furnace continues to become warmer and warmer, as the heat its making is not being taken away by the blower fan a 2nd switch comes into play and turns off the oil or the gas part of the heating side of the furnace so it does not over heat. Furnace Not Working—Oil Burner First of all, if the oil burner goes on and off too much, clean or replace the filter. If it takes to long to get warm the the people that installed it needs to come back out and check the gas pressure in the gas valve. A defective control board causes the blower to run continuously. The high pitch noise doesn't start until the burners kick on. Wiring your gas furnace to a generator is a project that's frequently either over-thought or not thought of at all. Furnace turns on and off repeatedly : 1. Mike T 2005 Winnebago Voyage 33V, Workhorse W20, with '06 CR-V in tow, SMI 4 wire Braking system, Blue Ox Underskirt, Pressure Pro. Your fan limit switch is located directly under your furnace hood and controls when your furnace blower turns on and off. i put a new valve on because the inside panel said it was one of 4 things, gas pressure,gas flow, flame sensor, or the valve. When this happens, the furnace will shut off after running for a few minutes. When the RV reaches the desired temperature, the burner will shut off, but the blower will keep running for a little while longer. Distributes the warm air with a blower motor through your home's ductwork. Just remember, if the furnace is not sounding right, it's best to call a qualified technician to inspect your HVAC system to make sure everything is in proper working order. The fan can run for a long time, often until the furnace starts again. In this discussion, our focus is on gas furnaces. Dirty Burners. Refer to your user manual to locate the ignitor. Does IBM start on heat speed 20 seconds after burners light? Does main burner remain lit until heat call ends? Does thermostat maintain reasonable room temperature near setpoint? Set thermostat to off position (W to C = ØV) Does gas valve shut off immediately? Does IDM shut off after ten second post-purge? Does IBM shut off after a max. A probe inside the switch monitors the temperature of the burner assembly to turn the fan on once the burners are hot and turns the fan off once the burners cool down (when the thermostat stops calling for heat). To check if the fan belt is at fault, perform the following: – Start by flipping off the furnace, including the shut off of the circuit breaker found at the electrical panel. Furnace turns on and off repeatedly : 1. Here's a burning question we hear from Lawton, Oklahoma homeowners: "Why won't my furnace shut off?" To answer this, we need to know what you mean by that since it can be interpreted in different ways. Furnace shuts down- Because your furnace has to run longer to heat your home, the heat exchanger overheats, causing the furnace to automatically shut down. If it takes to long to get warm the the people that installed it needs to come back out and check the gas pressure in the gas valve. Tempstar furnace burner comes on stays on 10-15 seconds and shuts down. First of all, not knowing what you are doing with a gas-fired appliance can be dangerous, no matter how easy it looks on YouTube. Beckett burner turns on, nice flame, runs for maybe a few minutes and the burner shuts off while the blower stays on. So during the night I noticed the blower was on for what seemed like a long time. Most of the time after three tries the furnace will and go into a lock out condition until you turn your power switch back off and on again: Your furnace will not ignite the gas to produce heat for your home. • When proper temperature is reached the burner will cut off, blower will continue to run for a short time. When proper temperature is reached the burner will cut off, blower will continue to run for a short time. If you own a gas furnace, keeping the unit in top running condition is important for the safety of the home's occupants. Without that signal, the control module shuts off the gas valve and then tries starting the furnace again. The drum the lint does get past the basket and then accumulates in the vent and also the. Dear Brent: There could be a few reasons why your furnace is leaking water, but let's start with the most likely one: a condensation leak. So take that into consideration before you attempt any of these troubleshooting steps. Then the main blower starts working and the whole thing stays on for 2-3 minutes. A built-in thermostat called a limit controller prevents overheating. If you furnace starts to click, the blower turns on, and then back off again, you could have a problem with your flame sensor. i call for heat and the furnace lights fine. It automatically shuts off the fire in the furnace if the temperature becomes too high until the furnace has the chance to reach a safe temperature. Call a professional to have your flame sensor checked and cleaned. Furnace under fired. Like any other kind of central heating system, thermostats are used to control forced air heating systems. The burners will not lit unless this knob is in the on position. It continues to this anywhere from 5 to 20 times before completely shuting down. If you see or hear the fan turn on, your blower motor is not the culprit. The most common reasons for replacing the blower motor Skip – York Furnace Blower Wheel Replacement (Part #S1-02619654709) - Duration: 4:33. Problem: Your furnace main burner ignites, the main burner stays on for 8 to 10 seconds, then shuts right back off. Ensure that all fuel-oil manifold and atomizer/safety shut-off valves are shut. theres two motors in your furnace. 2 days ago, furnace air intake ducts start emitting a "burning odor" when the unit is running. WARM AIR FURNACE MULTIPOSITION DO NOT ATTEMPT TO START THE BURNER WHEN shut off electricity and fuel to furnace when servicing. My furnace starts then shuts off. So in normal operation the furnace plenum temperature will reach the OFF limit and turn off the burner. set your start to fan on and listen to it start up. It just doesn't stay on. Could be that the air filter is so dirty its causing the sheetmetal to colaps when the blower starts and stops. The blower will continue to run as long as the chamber is hot even though the thermostat is satisfied and the main burner is off. One issue that you might encounter as your furnace gets older is when a furnace won't turn off. The plenum cools off quickly and when the fan stops, the latent heat in the furnace warms it back up and the blower restarts for a short time. Wired wrong Correct wiring Faulty relay Replace relay BLOWER VIBRATES OR IS NOISY. Problem: The heater comes on, the gas lights, the furnace warms up, the blower starts then abruptly the gas cuts off. Make sure the manual shut-off valve is in the "ON" position. If there's a very small flame that starts first, and then ignites all of the main burners, that's an intermittent pilot type of ignition. and a time delay of about 35 sec, your blower will start at low speed until the control makes the necessary adjustments to operate the blower at either the low- or high-fire speed.