Sears Furnace Blower, off and on

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Old 11-02-07, 01:40 PM
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Sears Furnace Blower, off and on

Hey guys, every summer I take of my Sears Gas Furnace. Anyways I started up my furnace yesterday, and everything worked well. But what I noticed is that the blower would come on for about 30 seconds and then shut down for about another 20 seconds.
It would come on and off until the thermostat kicked off.


Any suggestions?
 
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Old 11-02-07, 07:45 PM
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We are going to need more info on this.

Model#?

Is the fan controled by a timer or fan limit?

YOu put your hands on the motor to see if it's HOT?

Direct or belt driven?
 
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Old 11-12-07, 07:08 AM
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It's a SEARS GAS-FIRED SPACE SAVER FURNACE Model #:867763270

According to a diagram on www3.sears.*om it has a (Control, Fan & Limit, part: 27055)

No i did not put my hand on the motor, should i place in while its runnin or when it stops.
What do i do if it Hot?

thanks
 
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Old 11-12-07, 07:20 AM
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According to a diagram on www3.sears.*om it has a (Control, Fan & Limit, part: 27055)
Take the cover off the Fan limit, and watch the dial.. There are 3 tabs. 1st one is your fan OFF, 2nd is fan ON, and 3rd is High Limit, shut off burners. Let us know what is happing.

No i did not put my hand on the motor, should i place in while its runnin or when it stops.
What do i do if it Hot?
Do it after it stops running, and KILL the power before you reach in there.

Do you have a fan switch on your t-stat, what happens if you leave that switch to ON?

I forgot to ask you in my last post, is the burners staying on the whole time?
 
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Old 11-12-07, 09:07 AM
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The fan switch on the t-stat is on.
(I tried it both on (Auto) & (ON). same result.

I will do the other when i get home tonight
 
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Old 11-12-07, 09:20 AM
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If it's doing in both mode, then sounds like the motor is on it's last leg.

Looking at the info, the furnace is an older furnace, maybe time to think of upgrading to a new high effecncy furnace.
 
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Old 11-12-07, 10:35 AM
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do you know how old the furnace is, i cant seem to track it down.
 
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Old 11-12-07, 12:27 PM
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Originally Posted by Jay11J View Post
If it's doing in both mode, then sounds like the motor is on it's last leg.

Looking at the info, the furnace is an older furnace, maybe time to think of upgrading to a new high effecncy furnace.
Sears has a replacement motor for $95.00. Would it be worth it just for this coming years.

Could it also be the fan limit switch?
 
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Old 11-12-07, 02:05 PM
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The best way to tell is hook up voltmeter test leads to the motor and start the furnace up. If the voltage goes to 0 when the motors goes off, then it's the fan control. If the voltage remains at 120 when the motor goes off then it's the motor or motor capacitor. Like Jay said, if the motor is shutting off no matter where you set the t-stat fan switch, it's probably the motor or it's capacitor. $95 for a motor isn't that bad. Just be sure to follow the # 1 rule- always replace the capacitor when you replace a motor.
 
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Old 11-13-07, 06:59 AM
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Okay, i went home turn on the furnace (T-Stat), blower came on and off, the MOTOR was NOT HOT.

I found my Fan/Limit Switch, i lowered the setting and the blower ran for about 25-30 min, until i turned it off.

When i returned the setting to its org. Temp Setting the blower/motor went on for 20 sec.. and off for about 20 sec. it kept cycling on and off.

I think its the Fan/Limit, I will replace it tonight when i get home.

Quick questions: There are (3) tabs on the wheel of the fan/limit, with a temp range 0 - 200. what is the best setting for the tabs?
 
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Old 11-13-07, 09:57 AM
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The limit side on your old control should already be set, so just use the it. Usually the limit is 190*F to 200*F. For the fan side, try a 120*F on and 90*F off for starters.
 
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