Blower challenges

[schmit]

Hey all, newbie here. I'm trying to assist the girlfriend w/ her wood stove and could use some guidance.

She said the fan isn't pushing out the airflow that it was. I watched the fan run and when it shut off, the motor spun freely for a while. I spun it with my finger too and it has no resistance... it's spinning free quite nicely. The info on the blower: Franklin Electric 1/4HP 115V 60hz 10.3a 1050RPM Cont Air Over.

After doing some reading on these forums, it appears that the capacitor could be a possible solution. The capacitor on this is very rusted, so I'm guessing it makes sense to replace this first.

My questions are - .
I've read different items about run and start capacitors. How do I tell which this is, or are they one in the same?

Also, from the reading I have done, it seems there is suppose to be a positive and negative terminal on the capacitor. Since it is so rusted, I can't tell which terminal is which, and I can't even tell what kind/brand/model it is. The wires going to the capacitor come directly out of the motor and both wires are the same color and both are silver wiring. How do I determine the replacement part I need, as well as determining which terminal is positive or negative? EDIT: I took a closer look and found that the 2 wires from the capacitor are spliced in just outside of the motor. 1 goes to a blue wire that goes directly into the motor. The other appears to go to the control panel that is also connected to a thermostat

Lastly, when I drain the capacitor, can I just shut off the breaker and drain? The wires are soldered on the terminals, so I have to cut the wires. I'm not sure if I should kill the breaker, cut the wires, and then drain, or kill the breaker, drain, and then cut the wires?

I've discontinued the use of the stove for now. I don't want to damage the blower if it isn't already damaged. If I'm off-base here, I'd appreciate any guidance. Thanks a bunch.

 

[begreen]

If the motor starts up and runs, the start capacitor is unlikely to be bad. One thing to check is the set screws on the fan that anchor it to the motor shaft. If the motor turns freely, but it takes time for the fan blades to get spinning, this is the first thing to look at.

 

[Channing]

When my blower died. Harmen wanted big bucks. I found it in Grainger for a lot less. It's just a blower off a hot air funace.

 

[Corey]

IMHO, it's unlikely you'd have a start capacitor on such a small motor in a low torque application such as a blower....maybe if it was a compressor motor or something, but doubtful on a blower. Most likely it's a PSC or permanent split capacitor motor. To get to some of your questions:

I don't know what reading would suggest there is a + and - on the cap. It's a bipolar cap in an AC motor so that would pretty much go out the window. Two terminals could be connected in to either line. The fact that both wires are the same color also indicate that there is no + and -.

The capacitor should be connected across the windings of the motor, they would drain the cap anytime the circuit is not energized. So draining is not explicitly necessary. However, since the motor may be malfunctioning, and you can't be sure exactly where, it probably wouldn't be a bad idea to be 100% sure the cap is drained before working on it. Trip the breaker and/or unplug the motor, then if you don't mind a few sparks and a possible "POP", you can simply stick a screwdriver across the terminals of the cap to make sure. If you want to be technically correct, put a high value resistor across the terminals...ie 100 Kohms and give it a few seconds. You can then probe the terminals of the cap with a volt meter to make 100% sure it's dead.

For replacing the cap, there should be a marking somewhere stating the capacitance in microfarads or "uF" you'd want to get a motor run cap of roughly the same size. For a 110VAC 1/4hp motor, I'd guess somewhere around 5uF / 300V capacitor.

 

[schmit]

If the motor starts up and runs, the start capacitor is unlikely to be bad. One thing to check is the set screws on the fan that anchor it to the motor shaft. If the motor turns freely, but it takes time for the fan blades to get spinning, this is the first thing to look at.

The motor seems to start up fine and it doesn't take time for it to get spinning. She said it isn't blowing as hard as it did last year.

I just got more info out of the g/f. She said that manual setting use to run the blower all the time when it was pushed in. It only does it now when its cold. last week, the breaker to the blower was tripped in the breaker box. Also, when the stove is stoked, the blower will run for about a minute, then shut off for 5min. The manual switch for continuous run of the blower won't work when it shuts off for that 5min period (only when stove is stoking hot). When 5min is up, the blower will kick back on for another min, and then back off. It also does this when it's set to auto (the thermostat). The stove is running pretty hot she said and said it should be blowing harder... and the manual thermostat setting should turn the blower on at all times.

Maybe i should just call furnace repair..

 

[schmit]

IMHO, it's unlikely you'd have a start capacitor on such a small motor in a low torque application such as a blower....maybe if it was a compressor motor or something, but doubtful on a blower. Most likely it's a PSC or permanent split capacitor motor. To get to some of your questions:

I don't know what reading would suggest there is a + and - on the cap. It's a bipolar cap in an AC motor so that would pretty much go out the window. Two terminals could be connected in to either line. The fact that both wires are the same color also indicate that there is no + and -.

The capacitor should be connected across the windings of the motor, they would drain the cap anytime the circuit is not energized. So draining is not explicitly necessary. However, since the motor may be malfunctioning, and you can't be sure exactly where, it probably wouldn't be a bad idea to be 100% sure the cap is drained before working on it. Trip the breaker and/or unplug the motor, then if you don't mind a few sparks and a possible "POP", you can simply stick a screwdriver across the terminals of the cap to make sure. If you want to be technically correct, put a high value resistor across the terminals...ie 100 Kohms and give it a few seconds. You can then probe the terminals of the cap with a volt meter to make 100% sure it's dead.

For replacing the cap, there should be a marking somewhere stating the capacitance in microfarads or "uF" you'd want to get a motor run cap of roughly the same size. For a 110VAC 1/4hp motor, I'd guess somewhere around 5uF / 300V capacitor.

Thanks Pyro. I edited my original posting w/ more information and also posted more info that the g/f just relayed. Both wires from the cap were spliced in next to the motor. One wire from the cap goes into a blue wire > into the motor. The other one goes up towards the control box. The cap is extremely rusted and there are no visible markings any where.. it's all rust. The motor starts and runs fine except she said it doesn't blow as hard, which from my recollection, appears to be the case. She also said a breaker to the blower tripped last week. Lastly, the manual/auto switch on the thermostat doesn't appear to be working as it once did. When the stove is running hot, the blower will run for around a min, then shut off for 5min. When it shuts off for this 5min period, the manual switch on the thermostat won't start the blower The blower power appears to be cut off during this 5min period. But it will start back up on its own and repeat the cycle. With this, and the lack of blowing power, she's not stoking the stove because it starts running pretty hot.

 

[schmit]

Oh wow, I think I just figured it out, hahaha. The control box (where the wiring from the motor and thermostat meet), there is a pull chain switch on the outside of the box. With each click of the chain, the fan is variable. It goes through 5 clicks. High, Medium, Low, Off, Off. (Not sure why there are 2 "OFF" settings). Maybe one of the settings does something w/ the draft fan that is also wired in here.

I just ran the blower in manual mode and it ran for 3min, no problems. But when the stove is hot, it won't run for longer than a min without going off for 5min (and during the 5min off time period, I have pulled the pull chain and it doesn't click the fan on).

This is confusing... but I think I'm one step closer. I just need to figure out why the blower keeps shutting off for 5min when the stove is hot and the manual setting won't work.

 

[begreen]

If it's on a metal tab, try moving the thermostatic snap switch that controls the blower closer to the metal of the stove. Or perhaps it just needs replacing. If so, be sure to get one with the same specifications (on/off temps and amperage). These are relatively cheap to replace. Be sure to uplug before servicing.

 

[schmit]

If it's on a metal tab, try moving the thermostatic snap switch that controls the blower closer to the metal of the stove. Or perhaps it just needs replacing. If so, be sure to get one with the same specifications (on/off temps and amperage). These are relatively cheap to replace. Be sure to uplug before servicing.

It's mounted on the side of an electrical box where all of the wiring goes into. The switch is within an inch from the metal on the stove. The electircal box is mounted on the stove wall. The switch appears to be working?

Basically, what is happening is that when the stove is cold... I can push the button on the thermostat in for manual, and the blower will kick on, and run and run just fine.. While I'm doing this, I can hit the snap switch on the fan control box, and the fan will change it's speeds... High, Medium, Low.. Off and Off. (the manual for the stove says that the blower has a high and low setting.. but this toggle will give me 3 speeds?). But, when the stove is stoked and heated up good, the blower will run for only 1min (or less), then it will shut off for 5min. During this time, I can not turn on the blower w/ the manual button on the thermostat.... it doesn't do anything. I also snap the toggle on the fan control box and it won't turn the blower on at all. The blower is off and the stove gets hot and hotter. Around 5min later, (both in the auto or manual thermostat settings), the blower will kick on again for 1min.. but then back off for another 5min. Originally, the g/f said the blower wasn't blowing as hard. I believe I found the culprit on that. But I'm afraid of stoking the stove back up because I don't want it to overheat. The thermostat works in lower heat... Blower kicks on around 140-150 and off at 100 or so. It also has a higher setting of around 200. When the stove gets hot... the blower works, turns on/off, etc.. But the manual push button is disabled when the fan shuts off automatically.. and when the blower shtus off, the thermostat pegs out. It's running way too hot when the fan stops. I don't know... maybe it's running just fine? I'm worried because the stove is getting hot and the manual button won't work when it shuts itself off.

Could it be that the toggle was set to the medium/low fan speeds, causing it to overheat? Maybe now that I have the toggle on the high fan setting, it may function properly? Wishful thinking?

 

[Corey]

If I understand correctly, it sounds like you may be tripping a thermal overload in the fan motor. ie - when everything gets hot, the fan cuts out and there is no way to turn on the fan either by thermostat or by manual switch? But even though the stove is hot, after the fan is off for 5 minutes, it will come back on for one minute, run, then shut off again?

This strongly suggests the motor itself is overheating, not that the stove is putting out too much heat to the motor. Otherwise the fan would go off and stay off until the stove cooled down. I suppose a bad capacitor can lead to the to the motor running at a slower RPM (ie, lower air flow) and because it is running slower (ie below synchronous speed) it would run hotter and possibly overheat. So again, this points back to a possible bad cap.

 

[schmit]

If I understand correctly, it sounds like you may be tripping a thermal overload in the fan motor. ie - when everything gets hot, the fan cuts out and there is no way to turn on the fan either by thermostat or by manual switch? But even though the stove is hot, after the fan is off for 5 minutes, it will come back on for one minute, run, then shut off again?

This strongly suggests the motor itself is overheating, not that the stove is putting out too much heat to the motor. Otherwise the fan would go off and stay off until the stove cooled down. I suppose a bad capacitor can lead to the to the motor running at a slower RPM (ie, lower air flow) and because it is running slower (ie below synchronous speed) it would run hotter and possibly overheat. So again, this points back to a possible bad cap.

Correct. When the stove is hot, it will repeatedly come on for 1min, shut down for 5, and repeat this process over and over. While hot, when it shuts down for this 5min period, the stove pegs out the thermostat, but the blower will still kick back on repeatedly.. Yes, while it is off for this 5min period, I can't do anything to get the blower running, even with the manual switch... With the stove cold, the fan will run continuously on the manual setting.

I have a few pictures of the setup if it'll help - http://picasaweb.google.com/jzanti/Misc?authkey=_QDkugRG-Ho&feat=directlink

If anyone sees a place to oil that motor, can you let me know? I don't see it... sorry.

Thanks everyone.. I greatly appreciate your time and expertise.

 

[schmit]

i put a multimeter on the cap, and I got 1volt 0amps while the blower was running. When the blower was off, the cap showed 0volts 0amps. Not sure what this means, but figured I'd post it. When I tried to drain the cap, there were no visible sparks. After running the blower for a few minutes, another drain attempt on the cap didn't spark anything. I guess I'm replacing the cap tomorrow and go from there.

 

[begreen]

This appears to be a badly jerry-rigged furnace, not a stove. Exactly what is the make and model?

Did you understand that if the motor starts, the cap is not bad? The way this thing is currently rigged it is dangerous. There is a serious risk of a shock hazard.

The problem may be with the limit control. Please don't take offense, but it sounds like you may be getting in a bit over your head. I'm hesitant to guide further as the risks of error could lead to affecting the safety controls on this unit.

 

[schmit]

This appears to be a badly jerry-rigged furnace, not a stove. Exactly what is the make and model?

Did you understand that if the motor starts, the cap is not bad? The way this thing is currently rigged it is dangerous. There is a serious risk of a shock hazard.

The problem may be with the limit control. Please don't take offense, but it sounds like you may be getting in a bit over your head. I'm hesitant to guide further as the risks of error could lead to affecting the safety controls on this unit.

No offense taken at all. I'm a novice, so all input is appreciated. It's a Jensen 24A.

I did not understand that the motor wouldn't start if the cap was bad.

Hmm, ok. I guess I'll see what she wants to do with it from here. She has used the stove in this condition for many many years.. but it wasn't used over the past few years.. she just started using it again this winter and ran into these difficulties.

Thanks for the help.

 

[Corey]

I concur with BeGreen 100% except for the quote "if the motor starts, the cap is not bad" - This may be true for cap start motors and PSC motors which are operating with some moderate start-up torque. But that blower offers practically zero start-up torque, it may draw a little more current, make buzzing and humming noises, and/or start slowly, but I still think the motor would start.

If you have a volt/ohm meter, you could test the cap by removing it from the system, making sure it's discharged (screwdriver or resistor from above) then set the meter to read ohms (resistance) and touch the leads to the cap. You should see the resistance drop to a low reading when you touch the leads to the cap, then it will build back to nearly infinite resistance. If the reading never moves from infinite, the cap has failed open, if resistance stays at some low level, the cap is internally shorted. If you have a fancy meter that actually measures capacitance, just stick it on uF and see what the cap measures.

http://www.youtube.com/watch?v=JlwC_MyjEEw&feature=related
The needle is hard to see in this video, but notice how it swings to the right, then back to the left as he holds it to the cap...this is a good response. If the needle never moves to the right, or moves to the right and stays, that is a bad cap.

PS - be careful poking your meter around in amp mode - the cap discharge or shorting it across the line voltage will dump way more amps than the meter can handle...blow a fuse for sure, maybe even the meter.

 

[begreen]

The limit switch is located on the side of the furnace above the junction box that has the transformer and the pull chain switch. It is missing the cover on your girlfriend's unit. If you can post a clear picture of that switch I can take a look at the settings and see if anything stands out.

 

[schmit]

http://picasaweb.google.com/lh/photo/gjuHp4zJK

Thanks again

 

[schmit]

http://picasaweb.google.com/lh/photo/gjuHp4zJK

Thanks again

oops, the correct link: http://picasaweb.google.com/jzanti/DropBox?authkey=JM5RbjT4aIg&feat=directlink

 

[begreen]

OK, the settings haven't been changed from what I would think the factory would set them at. If you will note, there is a manual overide on the lower left of this switch. I can't read it, but does it say something like pull out to manually run the fan and push in for normal operation? If yes, as a temporary test you could try running it manually without a fire to see if the blower keeps running.

 

[schmit]

Yes, this is the manual button I spoke of. The fan works fine using the manual switch. It will run and run and run.

 

[schmit]

I put a new run capacitor on today. The fan is running much better. Now with a new capacitor, I can now see that it wasn't starting up well. It wasn't humming or anything prior to, but the fan is instant on now versus a cpl second delay. The fan appears to be blowing well too. The stove is stoked and running as it should now.

If anyone has a quick sec, can someone see my link above and take a look at the closeup of the motor. Where do I oil this thing? Or is it a sealed setup?

I greatly appreciate all of the feedback guys. The g/f plans on having someone undo the jerry-rigging and rewire it on its own breaker... as well as hooking it up to the house thermostat.

Thanks again. It's nice to know that there are people like you guys out there to assist the regular joe. Priceless. Thank you.

 

[North of 60]

Man those blower cups in that cage sure look like they could use a good cleaning. What does the filter look like or has it been running without one?

 

[schmit]

ya, I've vacuumed it out. The stove has been sitting for a few years, so the filter is clean (brand new). Do you see any oil ports on that thing? I don't...

 

[schmit]

ya, I've vacuumed it out. The stove has been sitting for a few years, so the filter is clean (brand new). Do you see any oil ports on that thing? I don't...

Can someone please tell me if this thing has any ports to oil? http://picasaweb.google.com/jzanti/DropBox?authkey=JM5RbjT4aIg&feat=directlink

 

[Corey]

I see no parts to oil. Most small motors have had sealed bearings for several decades. Look closely around each end of the motor If there is a hole / tube cast into the end cap which goes to the bearing, that would be where to put the oil. No hole means no place to put oil.