Oil burner tripping breaker

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Old 11-20-11, 09:34 AM
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Oil burner tripping breaker

Hi,

We have an oil furnace that has a Beckett AF oil burner. A week or so ago when we didn't have heat we noticed that its breaker was tripped. After resetting the breaker, it came on and ran fine until yesterday. Now it starts up, we get a flame,then runs for about 15 seconds and then trips the breaker.

Any ideas on what is causing this?

I looked at the blower motor yesterday and it looks OK. The slotted blower wheel spins freely inside the burner.

When the thermostat is set to FAN (not Auto) and the HEAT / AC is off, I don't get any air movement in the ducts. At the furnace, I can hear the relay clicking on as it tries to start the blower, but the blower does not come on.

We do also have an AutoFlo 200p humidifier that I think is not working. Its transformer is buzzing pretty loudly and I could not get it to turn on when I raise the humistat stetting to its max.

Do I have a bad blower motor?

I took it off yesterday (didn't disconnect existing wiring) to see if there were any oil ports. I didn't see anywhere where oil could be added so I put it back on.

Thanks
 
  #2  
Old 11-20-11, 11:30 AM
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Sounds like the breaker is tripping due to overcurrent. Sounds like it is the blower motor. IF it is 120 volt you could bypass the other furnace components and see if it will start.
 
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Old 11-20-11, 12:57 PM
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Blower Motor P/N

Here is the replacement motor, mine is a P/N 2456 cost = $45 on-line:

BECKETT BURNER MOTOR FOR MODELS AF, AFG and NX 1/7 HP, 3450 RPM, 120 vac, PSC (Permanent Split Capacitor), FRAME 48M, lower amp draw cooler operation allows for fewer failures and longer life.
Same as 21805R
Replaces: Beckett 2456, Beckett 2456U, SA55GYKPA-5733, SA55GYKPA5733 A.O.SMITH OBK6002, Carlin 98022S, Marathon 0701, Emerson 3248
 
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Old 11-20-11, 04:34 PM
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Is this "breaker" you refer to the red button on the burner control?
 
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Old 11-21-11, 07:56 AM
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It's the breaker on the panel that it tripping.

Thanks
 
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Old 11-21-11, 11:03 AM
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Blower motor is good

I took off the blower motor and plugged it into an AC outlet and it worked fine. I let it run for a few minutes and it didn't trip any breakers.

Could the problem be the relay switch or the transformer supplying power to the humidifier? I can disconnect the buzzing humidifier transformer since I'm pretty sure the motor inside the unit isn't working.

Thanks
 
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Old 11-21-11, 11:11 AM
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Or maybe the breaker is bad?
 
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Old 11-21-11, 12:59 PM
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Maybe a bad relay

After putting the motor back in and disconnecting the humidifier and water pump, I re-started the furnace and it did the same as before--fired up ran for about 30 seconds and then shut off due to the breaker tripping.

I tried it again and it didn't turn on. I could hear a buzzing noise so I tapped the side of the relay switch and it clicked on. This time it ran for about 5 minutes or so before shutting off. But this time the breaker didn't get tripped, it started making the buzzing noise like it did just before I tapped the relay.

Whatever is wrong with the oil burner it does appear that the relay is sticking or is bad, so I just ordered one on-line. I should have it tomorrow, so I'll install it and see what happens.
 
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Old 11-23-11, 04:19 PM
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Here's the latest:

The new breaker appears to have solved the breaker tripping problem. It tripped once right after I put it in but hasn't since.

Here's where things stand now:

When the thermostat asks for heat, the burner fires up and runs for about 2 1/2 minutes before shutting down. At this point, the Primary control goes into its lock out mode which lasts for about 5 minutes or so. The time frame on the shut downs is pretty consistent now every time I test and the breaker is not tripping anymore.

I went ahead and tested the CAD cell by jumpering its terminals (labeled "F") on my White Rodgers 668-451 primary control. This had no effect on the burner, it stopped working at about 2 1/2 minutes just as it did with the CAD cell connected.

Beckett tech support says that the problem's most likely with the primary control. They recommended that I replace it. They were very nice on the phone and cross referenced my obsolete P/N with a new one. I'll order it on-line this weekend and will hopefully get it in early next week.

The wife is starting to give me weird looks and a chilly Thanksgiving weekend won't help matters. We've got a couple of electric space heaters, so I doubt anyone will expire from hypothermia.

If anyone has any other input on this, I'm all ears.
 
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Old 11-23-11, 04:51 PM
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I suspect a problem with the fan control. The blower should have been on long before 2 1/2 minutes of burn time. I also believe the burner is shutting down due to the furnace getting too hot, causing the limit to open & breaking power to the burner.

If there is a wiring diagram on the furnace, how about posting a copy? If no wiring diagram is available, maybe a furnace (not burner) make & model would help.
 
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Old 11-24-11, 10:58 AM
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Overheating sounds about right

Thanks Grady, it does appear to get pretty hot just prior to shut down. Therefore, a fan control issue does make perfect sense. I'll try to locate the manual for the furnace, maybe it will have a wiring diag I can scan and post. I'll postfurnace make and model later today or tomorrow.

Have a great Thanksgiving and thanks again for your advice.
 
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Old 11-25-11, 08:27 AM
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Make and Model

I'm still looking for the manual, but not having too much luck.

Here is the make and model of the furnace:

Ruud / Rheem Highboy Model U0BB-112C-JA

Thanks
 
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Old 11-25-11, 10:28 AM
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Fan Limit Control shutting down burner

I just checked the fan limit control and it is indeed shutting down the burner. As the burner runs, the blower is not coming on so the heat is staying in the furnace causing the fan limiter control to spin until it shuts off the burner.

Therefore, I'm thinking that the problem is:

1. Primary control is not turning on the blower
2. Blower motor is having a problem
3. Maybe the relay is not switching as it should

Re the primary control, I'll hook up my multimeter between it and the blower and will check for voltage to the motor

Re the motor itself, I did test it on my workbench with 120VAC and it appeared to work fine.

Re the relay, if anyone thinks it would make sense to change it, I'll do it. I have a brand new one.

Anyway, I'll post the results of the voltage test in a few minutes
 
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Old 11-25-11, 12:59 PM
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Going to call a repair guy on Monday

I hooked up the multi meter and checked the voltage coming from the primary control to the motor it read 120V when I started the furnace.

Since it hard to tell for sure if the motor is running due to the igniter, I went ahead and used an outlet to power just the motor then looked at it by flipping up the igniter. It looked like is was running OK but I didn't feel a whole lot of air coming out of the registers when I checked them. Maybe the motor has two speeds and I had it on low?

Anyway, I'm out of things to try so I called a couple of local repair companies. Both were closed through Monday, so we'll be using the electric space heaters to keep warm for the next couple of days.

Thanks very much to everyone who took the time to respond to my posts. Although I didn't get the furnace fixed, I did learn a lot from the experience and now know a whole lot more about my furnace than I used to.

Have a great weekend.
 
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Old 11-25-11, 04:31 PM
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The primary control has nothing to do with the circulation fan.

If you have a fan/limit control like this: http://customer.honeywell.com/techli.../L4064-1-3.jpg
Note: Yours may or may not have a button sticking out of the cover.
With the burner running & the middle pointer past the 6 o'clock position, check for 120 volts from "fan load" to neutral or ground. No voltage indicates no power going to the fan. If there are 4 wires to the fan/limit also check from "fan line" to neutral or ground. No power here would tend to indicate a bad relay.
 
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Old 11-30-11, 09:12 AM
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Circulation Fan is the problem

Over the weekend I got the circulation fan working by spinning it by hand a few times. It came on OK but did make a noise that sounds like it may have a bad bearing in it. With the fan working, the furnace did not overheat.

Had a tech stop by to look things over and to discuss options. He made some adjustments to the burner (new nozzle, oil pump pressure, etc.) and it is working fine.

He said that there wasn't much he could for the circulation fan and that if it is bad, we should probably consider replacing the entire furnace . He said a new circ fan with installation might run upwards of $500.

So now we'll be looking at replacing the furnace--might even switch over to natural gas so as to get off oil. I also called Ruud to try to get a p/n for a replacement circ fan, but their tech support guy said they don't keep records back 20+ years.

So I'll start researching nat gas furnaces, maybe get a couple of estimates and then will make a decision.

Thanks again for everyone who offered advice. At least we can say we tried.
 
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Old 11-30-11, 07:06 PM
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There should be numbers on the fan motor. If you can get those numbers (Make, Model, HP, Frame size, & number of speeds,) we can find you a motor at far less than $500.
 
 

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