Oil boiler runs pefectly for one hour and then reset button pops

Hello, I'm a new member. I have a Geminox CTL 35S oil boiler which supplies hot water and central heating. The oil burner is Bentone.

It has run well for the past eight years from new and has been serviced each year. However, this year it has started behaving stangely. It lights perfectly and runs for just over an hour - and then the reset button pops out.

What could be causing this? The water pressure is within parameters (starts at one and a half bars and goes up to about two and a quarter bars when hot). It is not overheating, either.

I have cleaned the inside of the boiler, checked electrodes, adjusted air/fuel mix, etc. but these have not had any effect. I can't see that the photo electric cell could be faulty, as it works fine for over an hour before defaulting. The flame looks good to me, too.

Any suggestions or help will be very gratefully accepted. Thank you in advance.

 

Welcome to the forums from overseas.

You said you had it serviced every year. Does that include the oil filter which may be an issue now.

 

No, the service didn't always include that - it depended on the pro and how busy he was! But I have looked at the filter and it is OK.

 

There could be any of several possibilities. I've seen restricted fuel lines cause similar issues. I would suggest installing a vacuum gauge either on the buner or just ahead of it. Fire the burner, pull up a chair, & watch the vacuum. If the vacuum continues to climb during the run, you have a restriction somewhere.
Another thing could be a burner motor going bad & drawing slightly high amperage. Again this would require montioring.

Even without instruments, you might be able to help us help you just by sitting, watching & listening for anything out of the ordinary.

 

Those are helpful suggestions. Thank you. I can get hold of a vacuum gauge - but how do I install it? Perhaps open the inspection hole and insert the probe and leave the glass off? Or how would I put the gauge "just ahead of it"?

I have a fairly good digital electric meter. Where exactly would I attach the meter's contacts to test amperage?

Many thanks again for the suggestions.

 

If you can post some pictures of the burner including near-by fuel system piping, it would be easier to explain how to install a vacuum gauge.

To monitor amperage, you would need a meter which would clamp around the power wire going to the motor.

 

So sorry not to have replied before. We were so busy that I made do with the reset button - but the problem remains as before. I now attach a photo. The burn marks by the inspection window are old (washer now replaced), so please do not pay any attention to that. Please advise where/how I should insert a vacuum guage and also what the amps going into the burner should be. The burner is Bentoflex ST120KAV - but the instruction manual doesn't say a thing about expected amps going into the burner! (BTW in France the voltage supply is 230V AC, as in almost all of Europe). Many thanks for any help you can offer...

 

That burner is completely unfamiliar to me & being so, I'm afraid I'm not going to be of much help.

 

Oh, Grady! Please don't abandon me! Nobody else seems to have any ideas, especially the so-called "chauffagistes" (heating professionals) here in France. The "pro" came for the fourth time in the past few weeks, twiddled with oil/air mix and pressure - and it defaulted again an hour and a half later, just the same. I have asked him each time (I don't like to TELL a pro!) whether the problem could be electrical, and he always just says no, without checking anything. I can't force him to check, if he refuses to consider the possibility. We had a different "pro" before him, who also just twiddled controls and refused to check electrics (Beyond his knowledge? They seem to be only interested in cleaning the inside of the boiler and twiddling the controls).

I got so deperate, as we have my elderly mother living with us (89 years old) and therefore need heating, that I sat in a cold cellar for an hour and half, watching the boiler and controls. The boiler worked perfectly upon reset, heating up and switching off/on normally via the water temperature thermostat. Finally, after an hour and three quarters, the boiler vented but there was no spark and it defaulted after fifteen seconds. It would not restart via the control box button; I had to wait for one hour before that worked.

So do you agree that the problem is almost certainly electrical? Oil seems to be passing through, as after venting and default there is oil in the interior of the boiler. I have changed the photo electric cell and electrodes - no difference. I have cleaned both the inlet pipe filter and filter cartidge in the pump - no difference.

Trouble is, I could spend a fortune trying one thing, then another: control box, ignition tranformer, solenoid valve, coil, motor, etc. I've almost decided that it would be simpler buy a new oil burner complete. What do you think? As always, thank you so much for your help and advice!

 

Some controls on US burners, once they lockout on a certain fault, will not allow you to reset them for anywhere from 30 minutes to up to 3 hours. Your control may be similar.

Is this yoiur burner? http://www.bentone.com.webadmin7.net...one_BF1_en.pdf

If so, at least I'll have something to go by. Thanks.

 

PS I should have mentioned that the oil burner is Bentoflex ST 120 KAV. There is an English manual at http://www.hkr.sk/pdf/manuals/en/17800116.pdf

You posted just before I put this last post.

 

I would agree the problem is rooted in the electronics somewhere. I wonder if the ignition transformer is being supplied with power (via the control) or not. Since you could not reset the control & from what I've read, you should be able to do so after 50 seconds, I'm suspecting a bad control. Likely a component breaking down with the heat of running & after it cools off, it will again function. I've had similar things happen on US controls & also Riello.

 

Many thanks for your time and effort!