disconnect the 2 wires connected on the pressure switch.....inducer motor should start working.....if work.....bad pressure switch

 

I just tried this. I unhooked the pressure switch, then turned the furnace on and nothing happened, the inducer did not start. I tried the trick with sucking on the hose and this time that didn't work neither. I couldn't get the inducer to come on at all.

 

You have to measure the voltage on the inducer. If inducer is getting voltage using an ohmmeter check for resistance thought the inducer draft motor winding

 

Whoa, slow it down a little, getting a little beyond my knowledge. A week ago I didn't know how to open a furnace, I'm just learning as I go. I'm good with tools, I got a multimeter, what's a draft motor winding?

Inducer motor energizes then closes pressure switch. Sounds like first board went bad cause high amp draw from inducer motor. With power off check to see how freely inducer motor spins, if any sort of resistance bearings would be bad, replace motor.

I tried this already as suggested from another forum I was reading, there's a grille over it but if I stick a screwdriver in there and flick the fan, it'll spin fine either way for a few seconds and come to a slow stop.

 

Inducer motor energizes then closes pressure switch. Sounds like first board went bad cause high amp draw from inducer motor. With power off check to see how freely inducer motor spins, if any sort of resistance bearings would be bad, replace motor.

 

Originally Posted by JJboy
You have to measure the voltage on the inducer. If inducer is getting voltage using an ohmmeter check for resistance thought the inducer draft motor winding
You can red motor winding resistance through the motor leads. If there is 0 ohms motor is bad.

 

Originally Posted by JJboy
You can red motor winding resistance through the motor leads. If there is 0 ohms motor is bad.

Sorry I don't understand, where are the motor leads?

tail wagging the dog....:wink:.again the pressure switch proofs out from the ID running thru the tube to give spak and main gas run

Sorry I can't understand this, what do you mean? What's spak?

...ring the motor winding meter jumps as if touching leads...then to the metal frame of the motor

I still don't understand, how do I ring a motor? I'm not familiar with any terminology.

no reading as if your holding the leads in each hand if it rings true

:huh:

take an extension cord and slip the motor(no need to remove motor) leads into it if it runs the relay on the SS board is shot from amp draws over time...need to change the board

You mean take the wires coming out of the motor and put them into the slots on the extension cord? You sure?

 

tail wagging the dog....:wink:.again the pressure switch proofs out from the ID running thru the tube to give spak and main gas run...ring the motor winding meter jumps as if touching leads...then to the metal frame of the motor no reading as if your holding the leads in each hand if it rings true take an extension cord and slip the motor(no need to remove motor) leads into it if it runs the relay on the SS board is shot from amp draws over time...need to change the board

 

no problem you have an ohm meter so what where're looking for is when you touch the probes together and when there seperated....forget the actual resistance reading when you put them one on each motor lead.disconnect the motor wires where they connect onto the relay board..that point is where the board sends the 115V to run it on a heat call(first item to run when the stat calls....now take the leads and touch one to each wire going to that ID motor if the needle or led screen moves to from 1.0 to 000 or some valve just need to see continuity again as holding the probes together....OK no to check to see if their grounded same setting on meter one to one wire then other lead to motor frame the meter shouldn't move then do the other same any value show or goes directly to .000 the motor is grounded.:thumbsup: if you have the readings i explained it might still not be the motor...take an extension cor and slid each motor lead into the cord the motor should run if its mnot mechanically fouled up......again this is all done with the motor inplace we are just working the wires....if the motor runs let it goe for 5 minutes then disconnect the cord grab the body of the motor see if its hot to touch or warm which is what we want...yes on warm the problem is the relay board.....sending 115Vs on a heat call.....get the info off the board tell you a soucre:wink:

 

I can do this but maybe I don't have to, let me know if this means anything........when I suck on the vacuum tube to close the pressure switch, the inducer fan starts right up no problem. I left it running about 10 seconds and when I touched it, it was hot. Does that mean anything? Wouldn't it be normal for it to be hot where it's a motor and running so close to the flame? If that doesn't tell you anything then I'll try what you suggested.

Oh, also I replaced the control board yesterday with a brand new unit straight from a supplier. Model number in my first post.

 

post some images, so we can show where are all parts

 

The old control board, does it look burnt on the left side? Is that bad?

The new control board hooked up.

 

If your meter has the ability to check amperage then do a check. Clamp around 1 of the motor leads. If you have any amperage greater than listed on the motor then motor is bad. Oh yeah all this while equipment is running or attempting to anyway.

 

Where's the motor lead? Where it connects to the board?

 

Yes the wire or wires from motor to the control board. Clamp around only one of those wires with the system energized. You should have something if the motor has voltage. By the way the discoloration on the board is common around resistors and capacitors. When they go bad they have burnt spots the pic didn't look all that bad.

 

so the motor runs with sucking on the PS but that isn't the sequence might be something thru the boars can somebody kick in that:huh: so the motor runs the pix is showing the atmospheric side of the unit basement temps no heat is rising there it all is going out with the ID presurizing the chamber.....so the motor was hot afttr 10 seconf soo hot you couldn't keep your hand on it?if so the motor is going off on internal thermal so it needs change out.call for the heat with the motor cool tell back if you get a sequence start to heat forget the readings and the meter might be worn bearings doe it spin free or does it brake after spin attempt....if the motor ran even with the PS tube trick the board is supplying 115V as should .....but maybe somebody can enlighten me on why it controls the ID should be the other way around

 

so the motor runs with sucking on the PS but that isn't the sequence might be something thru the boars can somebody kick in that:huh: so the motor runs the pix is showing the atmospheric side of the unit basement temps no heat is rising there it all is going out with the ID presurizing the chamber.....

Not really sure what all that means.....I guess?

so the motor was hot afttr 10 seconf soo hot you couldn't keep your hand on it?

I'd have to fire it up again to see, want me to do that?

if so the motor is going off on internal thermal so it needs change out

So the motor would be bad? Are you saying the motor needs replacing if it's too hot to touch?

.call for the heat with the motor cool tell back if you get a sequence start to heat

I might be misunderstanding you but when I turn up the thermostat and make the call for heat, nothing happens. No clicks, no motor, no relays, no flame. Nothing. The only thing I do get is 4 blinks out of the light on the control board indicating "Control is in lockout due to air not circulating (overheated)." But this doesn't make any sense, the unit's cold from being off all night (even the breaker is flicked off in the wall panel), and it doesn't even attempt to start up. When I turn the furnace back on, I get these 4 blinks less than 1 second later. And it's not continuous, only once.

Also after about 10 seconds I get the 2 blink code from the furnace itself, telling me the pressure switch is open and it should be closed. Same thing that started this mess.

forget the readings and the meter might be worn bearings doe it spin free or does it brake after spin attempt....

The inducer fan? Spins pretty freely if I stick a screwdriver in through the grille and flick it. I can tell it's not completely resistance free, it does slow down kind of half fast but it definitely doesn't come to a dead stop. It seems to me like it spins fine.

Thanks for continuing to help me out, sorry I'm having trouble understanding some of this.

 

Biggles, your messages (helpful) would be a lot easier to understand if you threw in a period now and then. They are no cost on my keyboard.

 

this may sound different but trace orange hose from pressure switch to draft inducer to small nipple take off hose and clean this port and start over see if works after you start system....pressure switch must reset after each cycle

 

I read this on another forum so I already tried that and was looking around for something skinny to poke into the hole.....at my feet was a 12 inch piece of copper wire with the perfect diameter to fit in there. Obviously this has happened to the previous owners before I guess. So I stuck the wire in and it went in an inch. I pushed in and out as hard as I could while trying not to bend the wire and it now goes in about 2 inches before hitting something. I kept jamming it in and out as hard as I could but the wire kept bending so I assume that's as far as it'll go? 2 inches? Is that what you mean and did I do it right?

 

I don't think you can get around replacing the inducer motor.

 

Do you know for sure it's toast? How do I tell?

I think you need to measure all safety switches first

http://s3.pexsupply.com/manuals/1257434354611/18944_PROD_FILE.pdf

I got the physical copy of that here in my hands. What do you mean by measuring safety switches?

 

I think you need to measure all safety switches first

http://s3.pexsupply.com/manuals/1257434354611/18944_PROD_FILE.pdf

 

I just checked Google to see what they look like, apparently the limit switch doesn't affect the lighting, only turns off the gas after a few seconds if they are open. I looked for a reset button on the roll out switch but I really don't think there is one. I see nothing that looks like a button resembling a nickle.

If you'll give me 10 minutes, I'm just uploading a video to YouTube. It shows everything.

 

Sounds good, but to test these components are not that bad

 

Thanks for hanging around and posting those pictures. The inducer connectors are nice and tight. The limit switch is in the ON position, I even flicked if off and on again. And the roll out is actually that thermal thing that hangs in front of the flame to tell the furnace if it lit or not. I cleaned that thing off last fall, that was the last issue I had, it was dirty and not reading right so the flame used to go out after a few seconds.

Here's the video I took, please help!

http://www.youtube.com/watch?v=hcSzvNU7HeU

 

When you disconnect the pressure switch hose does the inducer motor run?

 

You need to close the door safety switch.

There's no safety switch for the top, only for the bottom which I have closed.

 

Ok, let me think more about this problem:thumbsup:

 

motor

for the love of all things holy, you got your answer 150 replies ago. Get a new inducer assembly, not just the motor. The visible blades turning from the rear have nothing to do with the impeller (air moving device).
If you have 120 volts going into the motor and its not running, its the motor

 

for the love of all things holy, you got your answer 150 replies ago. Get a new inducer assembly, not just the motor. The visible blades turning:thumbup: from the rear have nothing to do with the impeller (air moving device).
If you have 120 volts going into the motor and its not running, its the motor

:thumbup: i was thinking the same but didn't know how to say without being rude. Open, you're making this much more complicated than it needs to be.

 

http://www.asi-heating-airconditioning.com/About_Furnace_Inducer.html

http://www.hvactechsupport.com/furnace-hotsurface-ignition.asp#Induced_Draft_Motor_Will_Not_Run

scroll down to draft inducer section.
http://arnoldservice.com/Troubleshooting_Heating_Problems.htm

 

I read through those, the only part I found odd was the first link:

When a gas furnace heating unit has 24 volt power applied to the “W” terminal at the furnace and the negative side of the circuit is present ion the “C” terminal (usually this is wired to ground or some metal part) the unit will start the heating sequence.

Is this referring to the C in the thermostat wires? I have C G Y W R on the thermostat and the same on the control board. Nothing is wired to C on either of them. Should something be? It wasn't in the past and this was working last spring.

Also I put the multimeter on the W wire on my control board and it's getting 28 volts when I flip the breaker back on and it tries to start up. So voltage is going to the board from the thermostat, why wouldn't it be going from the board to the inducer?

 

I found some more troubleshooting on Google which reads:

Find the blower relay, one side of which is connected to the thermostat. Set a multimeter to the 50 volts AC range. Put one of the leads on the terminal labeled G - this is one of the blower wires. Put the other one on C which is one of the transformer terminals. Set the thermostat as high as it will go. The furnace should light, the meter should read about 24 volts, and the blower should start up in a few seconds. If not, replace the thermostat.

The furnace doesn't light, the meter reads 0 and the blower does not start up in a few seconds. I replaced the thermostat with a much cheaper, much simpler one that was also working previously (older one I used to use) but I still get the same symptoms. Nothing changed.

Turn the power to the furnace off at the circuit breaker box. Set a multimeter to the ohmmeter setting. Put the leads on the relay's G and C terminals again. The readout should be 0 when you touch them and 1 when you separate them. If not, the relay is faulty. Label the wires so that you know where each one goes and then remove and replace the relay.

If it's talking about the thermostat wires on the control board (C G Y W R) then I tried this and it always reads 1, it never changes to 0. How do I change a relay? Where is it?

 

You do realize that all 115 volt motors you can simply wire straight to see if it comes on, don't you? Use the main power going to the furnace and wire it straight to the inducer blower motor, black to black and white to white. Cap the ground on the incoming, you don't need it for this test. Flip the breaker back on (obviously you need to turn the breaker to the furnce off before unwiring the furnace) and if the inducer motor comes on then we know it's not the inducer.

We do this all the time, very helpful diagnostic "tool".

 

Where's the wires for the main power going to the furnace? What do they look like?

 

You pull the service panels off of the furnace, the doors. The furnace itself will have it's own wires, connected to the control board, coming through the door switch, that the incoming romex will be wire nutted to. Most likely this connection will be in a box small metal box in the furnace. You disconnect those wire nuts and pull the wire over to the inducer motor which you'll have to unhook from the control board and possibly strip the terminals off of so as to wire nut them to the incoming main power wires. You may have to pull the incoming wires all the way out of the furnace so that they reach over to the inducer. Remember, the door switch and all will now be bypassed and the inducer will be controlled ONLY by way of breaker or light switch.

Just remove the doors and trace that wire down. You can't miss it, it'll stare you in the face.