The induced draft motor runs for a half second, then quits. No HSI glow or gas flow. LED on the circuit board blinks rapidly and continuously. According to the error codes on the inside of the panel, that indicates a "incorrect twinning" or "incorrect polarity". the solution given is to reverse the transformer secondary wires or the primary wires. I have done both with no change in the operation of the heater.
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Re: Heater won't light
Not having a make or model number, I can only give you generic information. However if you add more info, others and myself can give you a better diagnosis.
In order for a furnace to start that has an inducer motor, the thermostat must call for heat. Then the circuit board will flash rapidly. There should be power from the board up to the inducer motor. If there is too much resistance, the blower motor or pressure switch(s) will shut down the unit. I would suggest that if you can spin the inducer motor by hand, check for resistance. It may be frozen up or there may be water in the housing not allowing the blower to turn. Check for a plugged water drain at the bottom of the blower housing and make sure it drains. If the inducer blower does not even try to start, you will need to check for voltage from the circuit board. Not knowing for what you have for a model, I am unable to tell you if you should be checking for AC or DC voltage.
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This system will not have a pilot light, instead it will have an electronic ignition or hot surface ignitor. The problem can be a number of things. You can check to see the operation of the unit by having someone turn the thermostat on while you are at the unit and go from there. The order of operation will be:
Inducer draft motor starts (small motor in heat compartment), after the motor runs and pulls the pressure switch in, telling the furnace that its safe, it then starts the ignitor. This will either sound like a clicking noise until the pilot lights or there will be a orange glow by the burners, after a few seconds, the gas valve calls and the burners should ignite.
By doing this, you can get more information to what the problem actually is. If your unit fails to start the inducer draft motor, fails to call for ignitor, fails to call at gas valve, fails to stay on after ignition. Your system should have a control board with LED trouble lights also. If you can see blinking lights, count the number of times they blink, then look for a trouble code chart, usually on the back of a panel. Hope this helps!
I ran into a simalar problem and it was a short in the control wiring of the furnace. When there is a call for heat a relay closes to start the inducer the movement of air causes by the inducer closes the air pressure switch. This is where the problem starts.some where in the control wiring there is a dead short this causes the secondary (24volts ) to drop causing the inducer relay to open shutiing off the inducer which in turn opens the pressure switch removing the short and the cycle starts over again. The culprit in my case was the high limit switch which was shorting against the metal furnace housing. You can easily ccheck this by removing the two wires from the fan limit switch and powering up the unit to see if the inducer runs normally . If it does remove limit and replace if necessary.
hope this helps
Hello, sounds like the limit switch is opening on the furnace.Usually when a furnace goes off on its high limit is becuase the airflow is being restricted making the furnace overheat. a limit switch is there to protect the furnaace from overheating, most cuases are either dirt or the blower motor not running up to speed, anything that cuts down on the airflow will cause the high limt switch to open.
Ok so here is a sequence of the heater lighting and the solution for your problem...
1. Thermostat calls for heat.
2. Draft inducer motor starts.
3. Pressure switch attached by a small plastic or rubber tube senses the negative pressure produced by the draft inducer and closes.
4. Draft inducer runs for 30 seconds to a minute before you hear a gas hissing sound. The ignitor did not glow, the flame sensor (a small metal probe about 1/8" in diameter, with a white porcelain base) does not sense the flame, so after 8 to 10 seconds the hissing sounds stops with no ignition of gas to heat your home. Your furnace shuts down and goes into a lock out condition until you turn your power switch back off and on again. Then the sequence starts all over again with no ignition of the gas.
Solution:You probably need to purchase and install a new ignitor. I would suggest that you inspect your ignitor closely for cracks.Make sure you do not touch the ignitor with your bare hands. If you do not visually see a crack, then you could have a furnace control board problem or a limit, rollout switch problem. Please see "limits, rollout switches & furnace control boards" further down on this page. The furnace's control board might not be supplying the voltage to the ignitor. If your furnace lights and the gas stays on for 8 to 10 seconds, then shuts right back off, then you need to clean your flame sensor with light sand paper or steel wool. You might need a new flame sensor, but most of the time they can be cleaned an will work well after cleaning. Please see the pictures below to help you identify a flame sensor.
Thanks and I hope this helps. Feedback apprec.
Problem: Your furnace will not ignite the gas to
produce heat for your home. When a furnace has a bad ignitor what I see most of
the time is the following sequence of operation:
Thermostat calls for heat.
Draft inducer motor starts.
Pressure switch attached by a small plastic or rubber tube senses the
negative pressure produced by the draft inducer and
Draft inducer runs for 30 seconds to a minute before you hear a gas hissing sound. The ignitor did not glow, the flame sensor (a small
metal probe about 1/8" in diameter, with a white
porcelain base) does not sense the flame, so after 8
to 10 seconds the hissing sounds stops with no
ignition of gas to heat your home. Your furnace shuts down and goes into a lock out condition until you turn your power switch back
off and on again. Then the sequence starts all over
again with no ignition of the gas.
Solution:You probably need to
purchase and install a new ignitor. I would suggest that you inspect your
ignitor closely for cracks. Make sure you do not
touch the ignitor with your bare hands. If you do not
visually see a crack, then you could have a furnace control board problem or a
limit, rollout switch problem. The furnace's control board
might not be supplying the voltage to the ignitor.If your furnace
lights and the gas stays on for 8 to 10 seconds, then shuts right back off, then
you need to clean your flame sensor with light sand paper or steel wool. You
might need a new flame sensor, but most of the time they can be cleaned an will
work well after cleaning.
That thang might be sensing a lazy flame. In other words the flames took too long in the board's opinion to quit sensing the flame. Yall probably need to do pressure tap on the gas valve. Here is a realistic look at goodman fault codes and what to check fer and I am assuming you are not a tech and don't know this already and am hoping it helps:
Read one LED flash that stays on continuously to mean your furnace has no signal coming from the thermostat and will not operate. Turn the power off and check the thermostat for improper settings or connections.
Interpret one LED flash that blinks on and off to mean your furnace has locked out because it could not ignite after three tries, and must be reset. Interrupt power to your furnace for 20 seconds or lower the thermostat so your furnace does not try to heat, then reset the thermostat to the previous setting. After one hour of lockout, your furnace will automatically reset itself and try to operate as usual.
Decipher two LED flashes to mean the draft blower is not working, or your furnace has a short in the pressure switch circuit. Turn off the furnace power and repair a short or replace the pressure switch.
Read three LED flashes to mean your furnace has an open pressure switch circuit or it has an induced draft blower operating. Check the pressure switch hose of your furnace for blocks or an improper connection. Also, look for blockages in the flue, and tighten any loose wiring.
Translate four LED flashes to mean your furnace has a primary limit circuit open, possibly from loose wiring or blocked filters. Check and clean filters, tighten wiring and check the flue for blockages.
Interpret five LED flashes to mean your furnace senses a flame without a call for heat. This could be from a gas valve closing slowly or a burner flame lingering.
Read seven LED flashes as a warning of a low flame sense microamp signal. This could happen with a coated flame sensor or a lazy flame from poor gas pressure. Turn off the power and adjust the gas pressure according to the information on the rating plate.
See eight LED flashes as meaning an igniter circuit problem due to a bad igniter or an igniter connected improperly. Replace the bad igniter or check the ground wiring, making necessary corrections.
Decipher nine LED flashes to mean the high-stage pressure switch circuit will not close during a high-stage-induced draft blower operation. Your furnace may have a pinched or blocked pressure switch hose, a blocked flue or loose wiring.
Read continuous flashing on the LED to mean your furnace has a reversed polarity of 115 volts. Turn off the power and correct the wiring polarity after reviewing the wiring diagram.
Now here is how it should all go down:
Bottom dollar: it all goes back to type of gas, the initial setup, the pressure tap. and how it is wired up to begin with. This will give you an idea where to start I hope.
There is a induced draft motor that will run first to purge the combustion chamber and induce a draft, a pressure switch closes proving an induced draft exists, thus allowing the spark and pilot gas, or hot surface ignitir and gas to pilot rsil and /or burners, a trial period for ignition about 30 seconds each for 3 attempts will be made and if not lit by the 3rd attempt it locks out, requiring a reset of power to unit to reset the module or circuit board etc. 1st see what motors running, is it the flue exhaust motor/induced draft??
From what I saw when I googled you furnace it has a hot surface igniter. It only gets hot when it's time to light the furnace. You should be able to see it glowing red when the furnace is trying to light. The furnace has a safety feature which shuts the gas valve when it doesn't detect a flame to prevent gas build up in the furnace. There are other safety features also. If the draft inducer motor isn't running the gas valve won't open. Overheat switches some of which have to be reset manually. Adjust the thermostat until it calls for heat then observe what is or isn't happening in the furnace. It will go thru a purge cycle first. The draft inducer motor will run to do this. After the purge the hot surface igniter should get hot a glow, then the gas valve will open and the burner will light. Let me know what you find.
f this is a metal vent 80% furnace,Turn Furnace off and remove the vent that connects to furnace and see if it is plugged.
If this is a High Eff furnace witrh pvc vents for exhaust and intake air make sure they are not plugged on the outside.
Turn thermostat all the way up,turn furnace off and wait a few minutes.This should reset any control board fualt.
Turn the furnace back on, if you have a glow coil ignitor it should glow red and then the burners should ignite. If this doesnt happen then:
On High Eff Furnace if the glow coil does not glow red, remove the combustion door to the burners, turn furnace back on, if the glow coil glows and burner ignites, you have an obstruction in the intake air side. If it still does nothing then:
Use caution and remove the exhaust vent from furnace, start furnace, if furnace runs then you have a problem with the vent system