Gas and Oil Home Heating Furnaces - Inducer help

I have a goodman furnace. The inducer will not shut off unless i turn the power off to the furnace, wait, turn the furnace back on and then the furnace runs to theres no call fo heat. But every time i have to turn the power off. What could this be?

It's locking out for some reason.

You need to take off the biggest front panel from your furnace and try to observe the ignition process and fire-up (if it even makes it this far), and tells us what happens in the sequence. Time the various strages in the sequence. Also do you have let's say a Honeywell or White-Rodgers control board inside (a white or gray square box that has maybe 6 or 7 wires attached and measures about 4 x 6 inches in size?) You have hot surface ignitor right?..that glows orange? See if you even see it glow bright yellow- orange. This will take about 30-45 seconds for that to happen once you set the stat to call for heat. Get back with us.

furnace comes on like normal once i turn power back on. Inducer comes on, gas charges, ignitor comes on, furnace fires up, brings house to stat setting and then shuts off gas then shuts on main blower. Inducer stays on until i kill main power. Also white-rodgers board. also furnace only stays on for 10 minutes the shuts down.

Is there a black relay inside the furnace up by the induser. When the induser is running and shoulldn't tap it.

No black relay near it. I follow the wire from the inducer to the circuit board, no relay.

Does the indoor blower stay on as well? I'm wondering if the furnace is going off on limit. You said it only runs for ten minutes? Then waht does it do?

thanks for answering me again.

main blower shuts off like normal. first burners go off then about a minute later the main blower goes off. But inducer is always one unless i turn power off. Then i turn power back on and furnace fires up like normal for another 10 minutes.

From the sound of it, I would have to agree that it may be a bad relay on the control board. The relays should look like black boxes on the board about 1" x 1". Tap on each one and see if the inducer goes off. There is probabl 2 or three on your control. 1 for the blower in A/C mode, 1 for the blower in Heat mode and 1 for the draft inducer. (I'm assuming.)

Here's a link that has your board if that's what it is:

http://www.myhvacparts.com/Catalogue/Printed%20Circuit%20Boards/Goodman%20Control%20Boards.htm

thankyou for all your help

Ill try tapping the black boxes

thanks for answering me again.

main blower shuts off like normal. first burners go off then about a minute later the main blower goes off. But inducer is always one unless i turn power off. Then i turn power back on and furnace fires up like normal for another 10 minutes.

Have you tried, rather than shutting off the furnace altogether, simply turning the thermostat way down to see if it goes off? What I find interesting in this post of yours I just quoted is the fact when you say you turn the power back on, it fires up again for 10 minutes. As if it is not really through calling for heat. (Unless of course there is a many minute interval from the time you shut off the furnace to the time you turn it on again, which simply could mean that your house got colder and is now calling for heat a second time).

If what I say does not apply, then maybe the sequencer is stuck open (a relay to the inducer) and located on some of the furnaces I have worked on, in the main electrical box behind the furnace switch, but inside the furnace, just behind the switch)

even with the thermostat in the off position, inducer will stay on.

The white wire from the thermostat connects to one one the inducer wires, is that normal. I cannot find a wire diagram anywhere on the web. Do you know where I could find one


Thanks

Take a closer look. The thermostat wires are thin gauge (like doorbell wire) and are 24 volt and the inducer runs on heavier wire that is 120 volt. So, it can't be. Not unless someone there did some tinkering and got it wrong.

On furnaces I have worked on, the inducer motor is where the power winds up after sending current to the blower door safety switch and then to the thermostat and then the sequencer that I previously described where then 24 volts gets relayed to 120 volts to the inducer. That is why I'm thinking the sequencer is stuck.

If you don't have a tester, I would disconnect the white thermostat wire (that would be your return from the thermostat) from the terminal in the furnace and see if it still runs. If it DOES, then it is not the thermostat. But if it stops running, then it IS the thermostat.

Ill taking the white wire off the thermostat first.

One wire goes from curcuit board to the inducer directly (black).

The other inducer wire (brown) is connected to the white small thermostat wire along with a red small thermostat wire. white goes to the circuit board the red look like it goes to the humidity dial on the main intake .

just followed all the wires, i was wrong. both inducer wires go directly to circuit board on neutral (white) and on hot (black). from what i can read on the board, everthing is in the right spot.

I put in a new thermostat 2 weeks ago becouse I thought that was the problem, it didnt fix it.


Theres a red light on the curcuit board that is always on. I cant find codes for that board any where. any suggestions?

Thanks

PS now the furnace stays on ti thermostat turns it off, except for the inducer it still stays on. I must have touch something right

I don't follow your last 2 lines of your post. But that aside for a moment, by what you are saying with the inducer wires traced to your board...it sounds like YOUR Goodman furnace may be of some newer variety (the kind where they put all kinds of black box relays and blower timer switch on the circuit board, as opposed to the older late 80's high efficiency Goodman's I am working on that have simply an ignition control board and separate (like a Honeywell) fan switch. What year is your furnace, out of curiousity, and maybe a model #.

model number gmp100-4 1993


I tried turning thermostat way below house temp but the inducer still stays on


the board part number is B18099-06 it has 4 little black boxes on it.


COuld it be a bad flame sensor. Meaning the flame sensor is telling the circuit board that the flame is on? How can i test it to eliminate that possibilty?

A flame sensor is out of the mix if you don't get flame. If JUST the inducer runs, either it is in some kind of lockout after there WAS a flame, and it went out prematurely, or no flame EVER came on. Which does YOUR furncae do? Take off the big furnace cover and have a look while the furnace tries to run through it's series of operations: Thermostat calls for heat, inducer runs because it is trigered to do so...soemtimes on a delay by a relay switch, flame ignitor or pilot system tries to light, burner flame comes on, flame sensor senses burner flame and keeps going.

But I have to stop here and ask you if you have a hot surface ignitor that just glows bright yellow-orange to fire up the gas? (the older Goodman's I work on do)...or does your furnace have a pilot light that comes on?)

When you said you have black boxes on the board, now I know you have one of those open solid stater circuit boards and you may even have the kind of furnace then whose blower fan works on a timer rather than heat increase type fan switch.

..........


I just worked on a furnace today and correctly fixed the right problem: Ventor did not come on, so then NOTHING came on. After making sure 120, 24 volts, loop thru call-for heat-thermostat, interlock blower door switch good/120 there, and repeated click sounds coming from the metal case housing the ventor motor relay switch (the sequencer), that is what was out and I got new one for $15 and installed it. A fairly quick operation. I wish I could charge $1200 for this work. :)

About 2 years ago I had to replace my next door neighbor's high efficiency gas furnace control board (the kind you have that has many wire terminals and many black boxes on it, as part of the solid state system got fried as the manufacturer had it installed too close to the heat box and it melted.) They redesigned the njew replacement control board. It cost about $110. (To date, I have never misdiagnosed/installed an unneeded furnace part. Part skill and part luck, maybe. :) )

Thanks for helping again

When i turn power back on, the inducer comes on (with or without the thermostat call for heat). When the thermo stat calls for heat, the hot surface ignitor comes on, then flames. Once thermostat temp is reached, flames go out. The a couple minutes later main fan goes off. Inducer never shuts off to i kill the main power.

Everything seems to be on the circuit board except the big fan capacitor and the vac transformer.

I tested the inducer motor according to an article i found and it says its ok.

At every stage of the furnace starting up I here a clik. Inducer makes the vacumm model clik, then the gas charges, then clik the ignitor comes on then flames then clik flames go out.

It's probably one of those relays on your board, is stuck, would be my guess. But I don't want you to go out and buy a new board without trying to get other confirmation. Obviously something is stuck, and I can't think of anything else, with a stat disconnected, that would allow the current to keep coming, when it shouldn't.

Do you know someone who will sell you furnace parts? They might also offer their opinion on this, especially if you tell them you wil buy parts from them.