Oil boiler shutting down for no reason

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Old 11-28-02, 05:44 AM
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Oil boiler shutting down for no reason

About a week and a 1/2 ago, we woke up to no hot water in the house. I went downstairs and found that our oil fired Weil-Mclein was in "reset" mode. I pressed the red button and it fired right up. Two days later, it did the same thing. I called service, they replaced the nozzle and oil tank filter and all was well again. Then, less then a week later, it did the same thing. Service was called yet again. The guy replaced the nozzle, adjusted the air flow and played with the ingnitor bars. That was last Sunday. Last night (Wednesday) it shut off yet again!

From what I understand, the boiler will go into reset mode only if the optical sensor does not sense the flame after a certain period of time.

What could the problem be? I figure we're getting oil because the unit works fine when it's "on". What would be the cause of this? It always goes into reset mode and shuts down when we're asleep or not at home.

I'd call someone today, but given that it's a holiday and we technically have heat, I'm sure they'd come out later or brush it off to tomorrow.

We're getting a little frazzled with this. We had to change our Thanksgiving plans a bit to ensure that we'd be home tonight to make sure the house didn't freeze!

Thanks in advance and Happy Thanksgiving!
 
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Old 11-28-02, 10:18 AM
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oil burner

Did you change the photocell on this burner ED
 
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Old 11-28-02, 03:55 PM
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No, that hasn't been changed. Good idea though!

I was actually next to the boiler today when it kicked on. The pump came on then no flame or "crack" of the ignitor. I stayed on, then shut off. So, I'm starting to think this is related to the ignitor.
 
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Old 11-29-02, 04:25 PM
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oil burner

Call that guy that worked on it. He should have to fix it.There can be a lot wrong here. Did he set the electrods right.Did he put in the same kind of nozzle. Are the insulators good? Last here did he check out the burners transformer? It can by weak ED
 
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Old 11-29-02, 05:24 PM
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They were back today...4 of em! They replaced the nozzle again with the same size that was just put in less than a week ago. I know that because they left the case for the nozzle behind each time. They also replaced the cad cell eye, I understand that "senses" the light from the flame. Now, I would think that this is an ignition problem. The burner is not firing at all, I've heard it happen when it does this. The sparker thing does not "click" and after about 40 seconds of the pump running and no flame, it goes into reset mode. What would replacing the eye do? I would think the old eye was working fine because the unit shut down after not "seeing" the flame.
 
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Old 11-29-02, 05:29 PM
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oil burner

DID THEY TEST THE TRANSFORMER ON THE BURNER?????? ED
 
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Old 11-29-02, 05:47 PM
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Yes they did. And of course, it worked for them fine when they were here. I told them that I actually heard the unit kick on, the ingitor did NOT make the "click" noise, then shut off about 40 seconds later.
 
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Old 11-29-02, 06:18 PM
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oil burner

They did test the transformer how ?Could they pull a blue spark on it 1/2"to 3/4".If they are sure its good what about the insulators any little black like marks on them?I know this is far out but have ran into it. Do your lights dim at times? any new electric stuff put in . IN your home or close by. The nozzle they put in why didnt they leave the old one???? You say the same nozzle spray angle like 80 or 90 Deg. ED
 
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Old 11-29-02, 06:49 PM
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They pulled the tranformer off the blower, turned on the unit then used a screw driver to pull the spark from spring to spring.

The nozzle they used is an 80 degree, 1.25.

I don't think anything electrical has been put in around our street recently.
 
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Old 11-30-02, 04:35 AM
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Hello Glenn,

I had a similar problem on my oil fired furnace two years ago. The only difference is mine uses a smoke stack sensor instead of an electric eye (photo cell). But, both systems still use a main relay.

In my case, the problem was the relay that powers the burner assembly. The relay contacts were too far apart and the coil did not have enough pull to bring them in.

I opened my smoke stack sensor and found the contacts open when my thermostat was calling for heat. I tap the contacts with a plastic rod and they were immmediately pulled in and presto the furnace run fine until the problem repeated itself several hours later.

I permanently fixed the problem, by shutting off the furnace power and bending back the little metal stop tab on the relay to bringing the contacts closer together.

In your case this could be the problem, it could be a defective relay all together or dirty contacts on the relay.

Good Luck

TheZman
 
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Old 11-30-02, 06:32 AM
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ZMan,
Thank for the insight. I really appreciate that.

What kind of relay should I be looking for? I know the optical sensor on our boiler is somewhere near the sparker unit....
 
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Old 11-30-02, 06:44 AM
TheZman
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Hello Glenn,

The photocell wiring should lead to a control box (relay box) that has the main relay. The burner power wiring as well as power feed from your fuse box should also wind up in the control box.

In my case, the control box was on the flue along with the smoke stack sensor.

In your case, the control box is most likely right beside the iginition transformer on your burner motor.

Good Luck

Let me know, how it works out.

Regards The Zman
 
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Old 11-30-02, 06:56 AM
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ZMan,
Ahh! OK! I know where that is. It also houses the temp control knobs.

That seems to be working fine. The unit will kick on, it;s just that the ignitor will sometimes not work, hence it shutting off after no flame is detected.
 
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Old 11-30-02, 08:36 AM
bigjohn
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I want to address both of you>

ZMan- you probably defeated the safety function of your stack switch. You need to shut off the oil and see if the burners quits on a call for heat. Stack switches are usually either dirty or defective. Bending the internal parts around can defeat the safety function.

Glenn- it sounds like the cad cell is doing its job. The ignition transformer could be breaking down, it's possible that the insulators on the electrodes are cracked. Another thing to check is the setting of the elctrode gap and the distance that the electrodes stick out over the nozzle. There is a tool that the service guys should be using to set the electrodes. It has numbers on it which correspond to the nozzle angle. You just set the tool over the end of the nozzle and set the electrodes. It sounds like you saw the guy check the spark. It should have been fat, blue, and at least 1/2" long, 3/4" is better. It's possible that the relay in your primary control is malfuctioning, but the trans and electrodes need to checked out first.
 
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Old 11-30-02, 10:11 AM
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Thanks John, I appreciate it.

The spark pretty much looked like you and others have describes. I wasn't looking over their shoulders the whole time, but I'm assuming they used that tool to adjust the electrodes. It's been working good for just under 24 hours, so I'll be keeping my fingers crossed.
 
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Old 11-30-02, 12:50 PM
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boilers...

Some oil pumps have an oil basket strainer. If the filter at the tank is changed, they should also remove and clean or replace the oil basket strainer on the oil pump. I agree with one of the previous techs, the guy who bent the relay should have replaced it. It sounds like an RA117a stack mounted relay in which case he doesn't use a cad cell. Your primary control is different. You have a cad cell relay for a primary control. The cad cell is timing out perfectly as it should and lock out the unit. Sometimes when the transformer is swung down over to touch the electrodes, one of the springs may slide off the contact point. Electrode gap is critical also. A qiuck test to see if its a fuel problem is to first
a.) inspect the combustion chamber to make sure its not soaked with oil.
b.) use a flame mirror to see the electrodes
c.) fire up the furnace.
you should see a spark go from electrode to electrode (not jumping to any other metal objects
if it failed to ignite, your flame mirror should be covered in oil in less than a second. This will tell you if the problem is fuel or ignition to a point. The only other thing to really do is test the fuel pump pressure. minimum is 100 PSIG and when shut off it should maintain 80% of the operating pressure (on the test port)
 
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Old 11-30-02, 01:04 PM
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oil burner

Zman did you ever see a oil burner go BANG. dont mess with the stack control.They say the transformer is good lets go back to the insulators on the electrodes then. Put new ones in some times you cant see just where they can leak on you but they do. ED
 
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Old 11-30-02, 08:29 PM
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Is it possible to adjust the "timing" of the spark? It seems that there's a much shorter duration between the pump kicking on and the "tick" noise of the spark now.
 
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Old 12-01-02, 02:15 PM
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oil burner

Glenn You got me on this one!!!!!!!!!! LOST
Lets try this When the t-stat calls for heat it tells the stack control or what you have a eye to turn the burner on......... Now the burner will start and at the same time the ignition transformer should come on and light the burner. They should both run the whole time till the t-stat cuts it off. Now you can have whats called an intermittent ignition. The burner and transformer will come on at the same time and run for a little bit then the transformer will drop out and the burner should keep running till the t-stat turns the burner off
NO YOU CANT SET THE TIMEING
Now if you have an intermittent control and it dont work right you can put the transformer over on the same tie as the burner and they will both run all of the time that the tstat calls for, have done that a lot. ED
 
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Old 12-01-02, 02:59 PM
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I'm thinking it's the intermitent set up. I hear a "tick", then the flame ignites and stays on until the thermostat shuts it off.
 
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Old 12-01-02, 06:06 PM
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intrmittant or constant ignition??

shut off the service switch on the side of the boiler. Look under the primary control and count the number of wires. Constant igntion will have a black, white and orange. Intermitant will have an extra wire usually blue.
 
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Old 12-01-02, 06:42 PM
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Is that the unit that has the temp controls?
 
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Old 12-01-02, 07:08 PM
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controls

This is the thing about the size of a 4X4 electrical box just to the right of the transformer It will have a T,T,F,F terminal on it this is where your thermostat wires are connected to in most cases.
 
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Old 12-02-02, 04:27 AM
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Thanks! I'll give that a look and let you know what the wiring looks like.
 
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