Problem with Blower...


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Old 11-14-12, 02:50 PM
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Problem with Blower...

Hi Folks,

Hopefully someone can help me to isolate my problem a bit, I'm not very familiar with my furnace. I *think* that the problem is with the blower itself, or maybe the limit switch. The problem is that the furnace will fire up but then turn right off and the blower never seems to get started. Turning the blower control on the thermostat to "on" from "auto" does nothing, the blower still doesn't turn on.

But I need some help in diagnosing this, I'm not at all familiar with this setup. So how do I figure out what my problem is? We haven't owned this place for very long, but it looks like the blower is relatively new. At least there's another blower stashed under the furnace, looks like an older one that's been replaced. And the limit switch looks pretty bright and clean.

Any help is appreciated!
 
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Old 11-14-12, 05:57 PM
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that is an old horizontal flow furnace. Please post the model number.
 
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Old 11-14-12, 10:59 PM
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I would replace the pressure switch. "round and grey with the orange/red tube and two wires" to the right of the inducer fan.
 
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Old 11-15-12, 01:22 AM
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need to do some diagnostics before you just start throwing parts at it.
 
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Old 11-15-12, 09:35 AM
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Ahhh, so that's a "pressure switch". Good to know. And just in case the pic is difficult to read it's a Ruud UGYA-06NE-FR.

Thanks!
 
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Old 11-15-12, 11:06 AM
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You have a furnace with a Honeywell intermittent pilot ignition system that should light the pilot light each time the thermostat calls for heat.

Your description of what is happening is vague.

Turn up the thermostat and describe in detail the series of events that happen. The amount of detail you provide is the key in being able to help you.

Replacing parts before the problem has been diagnosed is a waste of time and money.
 
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Old 11-15-12, 04:55 PM
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Yes, vague at best. It's because I'm really uncertain as to what's happening and if I crank up the thermostat then whatever is happening has probably already happened by the time I get to the furnace in the crawl space under the house. OK, it's a bit better than a crawl space, but along those line. I'm in SoCal so no basement.

When I'm there long enough then I will hear and see the furnace fire up. I can see the pilot light up and then the burners themselves (or whatever they're called) when I've had the side panel off. At the same time I *think* that the blower starts up, but I'm honestly not certain if it's the blower staring up or if it's just the amount of noise that the burner makes. Anyway, then I start to hear some clicking sounds from the area where the pressure switch and the circuit board are located. I just haven't been able to tell for sure which one is making that clicking sound.

It's not a steady sound and I don't think it's a healthy sound either. At times it almost sounds like a short of some type, or maybe a solenoid, something like that.

So I really noticed that sound today when I was down there, but it was there before just not as loud.

And then after 1 or 2 minutes everything just shuts down. And again, nothing happens if I try to turn the blower on by moving the thermostat setting from "auto" to "on".

Thanks.
 

Last edited by Mikal; 11-15-12 at 05:39 PM.
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Old 11-17-12, 12:55 PM
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Any thoughts? How do I isolate the blower? Since the furnace seems to light up fine and then shut down I'd guess it must be the blower or one of the associated controls? Or to circuit board itself?

Thanks.
 
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Old 11-17-12, 01:01 PM
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You need to follow the directions already provided if we are to be of any help.
 
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Old 11-17-12, 04:37 PM
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OK, lemme try again.

Ruud Model UGYA-06NE-FR

1. turn thermostat up
2. pilot lights
3. burner fires up
4. blower may or may not start (leaning more towards it not starting at all now since a) no air ever comes out of the registers and b) turning the "fan" switch on the thermostat from "auto" to "on" doesn't turn the blower on)
5. a clicking noise is coming from the area of the pressure switch/circuit board area. i guess it may be a relay
6. after about 1-minute the burner shuts off
7. after some period of time the same cycle repeats

that's really about all i have.
 
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Old 11-17-12, 05:02 PM
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The part in the left side of your picture with the rotating dial and the red wire on top is the fan/limit switch.

It measures the temperature inside the heat exchanger, turns the fan on and off and shuts off the burners if the furnace overheats.

You can probably observe the dial turning over and shutting off on the limit switch.

Very likely, the fan switch portion is turning on 120 VAC to start the fan and it's the motor that's not starting just as you suggest.

If you open the fan compartment after the burners shut off, you are probably going to notice that the fan motor is hot, indicating that the fan has power to it.

Very likely the motor has quit running because the fan motor wasn't oiled.

There is some reasonable probability that if the fan motor is removed, oiled and reinstalled, the motor will be OK in the future. It's also quite possible that the motor has been damaged by being run dry and will need to be replaced.

This is a good time to consider whether you want to do the work of removing the motor and oiling it and/or replacing the motor. You will find it a pain in the neck to do that task, but it's something a determined DIYer with reasonable mechanical skills might be able to do.

If you want to avoid a dirty job, the alternative would be to hire a repairman to oil and/or replace the motor. If you do that, you may well get a repairman who wants to sell you a new furnace.

Think about what you want to do.
 
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Old 11-18-12, 10:38 AM
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Thanks. So I did manage to oil the motor with some 3-in-1, but it didn't take much oil and the fan does seem to turn freely. It's an Emerson ka55hxfwr-3683. So I'm wondering if I should try the capacitor? I think that's the capacitor below, not certain how I should test it, but probably a good next step? I was able to hear a low, background hum when I had the panel off the blower and tried to fire it up. And is that other little thing in the blower compartment a relay?

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Old 11-18-12, 10:43 AM
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There are two oil ports. The outer one is pretty easy to get to, the inner one usually requires that the fan assembly be completely disassembled to get to it. If you haven't oiled the inner one, you haven't done the job.

Without special equipment you can't test the capacitor properly. They cost $6-8 typically --- I'd replace it with a new one of equal or greater rated voltage and equal or greater capacitance (MFD).
 
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Old 11-18-12, 10:51 AM
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Yep, i was going to mention that I had oiled both the front & back ports...that back port WAS a major pain.

Will that capacitor have it's ratings labeled on it? Hopefully, but I guess I'll find out when I pull it out anyway. I tried to google the motor to find out what capacitor it required but no luck.

Thanks again. And on a Sunday yet!
 
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Old 11-18-12, 11:27 AM
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Yes, the capacitor will have the voltage rating and capacitance on it unless the label has been lost.
 
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Old 11-21-12, 05:35 PM
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Huh. So replaced the capacitor but had the same result. But when I tried giving the motor a helping hand by spinning the fan it took right off.

I'd like to think that it just takes some time for a newly installed capacitor to charge, but that's probably just wishful thinking?

So is there something else that I can try/test short of replacing the blower motor?

Thanks again!
 
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Old 11-21-12, 05:58 PM
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Nope.....capacitor doesn't need more than a blink of an eye to charge. That motor may have been sitting there stalled for a long time damaging the windings. I've changed a lot of them.....not too hard in most cases.

In looking at your pic it looks like the motor has seen a lot of action.....probably was running hot without cooling air based on the dust buildup.
 
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Old 11-21-12, 05:59 PM
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Yes.

Interesting idea though, I'd never thought of that one!


I'm a little surprised. The capacitor helps get the motor started and is switched out of the circuit after that happens, so a new cap might reasonably have been expected to solve the problem.

But fan motors can wear out eventually, and I think you'll need to replace that one.
 
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Old 11-21-12, 07:04 PM
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Yep, everything would seem to fit. I think I'll take that sucker apart again, but this time give it a good cleaning. Dumb not to have done that, but oiling the motor took a lot longer than expected and I was in a hurry to get it done before the football games started...

Thanks again, appreciate all the help, starting to get a sense of the system now.
 
 

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