Buderus GB142/30 - How many attempts to light (proof of flame) is normal/acceptable ?

Paul Wolf

My basic question is: 

Should my Buderus GB142/30 boiler light on the first attempt?  Every time? If not, what is an acceptable rate of retries (6A, 6L, 227) before a flashing hard lockout ?

If I recall correctly, when I first installed it, it lit the first time, every time. I didn't concern myself with it again until it started acting up many years later. 

 You can see the whole thread here:

https://forum.heatinghelp.com/discussion/162244/buderus-gb-142-30-intermittent-6a-sub-227-error-code-solved#latest 

(see most recent). 

STEVEusaPA

It should always light on the first attempt.

Paul Wolf

Hi Steve, thanks for the reply. I was afraid of that. I should've added, that when it DOES go out on lockout, it is usually when ambient temp and boiler temp is cooler (60 deg or lower). As mentioned above (in my other thread), it DOES NOT happen all the time. Though much less since it was "serviced" in April of this year.

Jolly Bodger

Has the heat exchanger been cleaned? That can cause unreliable ignition.

Ironman

By "serviced", do you mean the heat exchanger was properly cleaned, the flame sensor was cleaned or replaced, the ignitor was replaced; and most importantly, combustion was setup with a digital combustion analyzer to manufacturer's specs?

Paul Wolf

Up until last April when I called in a service tech, I had been maintaining the system. Am I an expert? No, but I can tell you I spoke with many techs over the years and with a few simple questions to them, I knew far more about this boiler than they did. I do not own a combustion analyzer, hence my call to a service tech, and I don't think my Bacharach kit from my old oil burner days would be of much value. :-)
Yes, Hx has been cleaned several times throughout the life of the boiler. HSI and anode rod as well. Many times by me, and once by the recent service tech in April. Each time, it improved the 6A/6L situations, but I honestly can't remember the last time this boiler EVER went for any length of time lighting on the first attempt. Early in its life, the UBA was replaced because of faulting out while under generator operation. I have also replaced the HSI and anode rod a couple of times as well as some O-rings on a couple of sensors. In 2015 the Hx was leaking and Buderus came out and examined it and warrantied me a replacement.
By "serviced", I watched him clean the hx (not like the manual recommends). He used a vinegar solution and I think he did it 2 times, but I didn't see him fire it up during either. I did see him do a combustion, smoke and pressure test using digital electronics, but he got a little short with me watching and asked me to go upstairs.
The notes he left on the invoice were :
"Cleaned heat exchanger and flame rod. Cleaned condensate drain. Adjusted gas to lean. Unit had been locking out".
This is a pic of the readings as he was finishing up. He MAY have tweaked it a bit more but I don't think so.
Thanks for all the help and comments.

Ironman

Those numbers are too lean. Are you on natural or LP?

Paul Wolf

LP...

Jolly Bodger

I have had a few boilers with burners like this that did not light regularly. We turned up the ignition RPM and that did the trick. Some you can do through the user interface and some need service tool software to adjust.

Zman

Ironman said:

Those numbers are too lean. Are you on natural or LP?

I agree but suspect the CO with go through the roof if he goes richer.

Has the ignitor been replaced?

jstratz

I don’t know if the Buderus has a similar burner setup as the Burnham and Munchkin or not, but those boilers I have seen the swirl plate by the gas valve crack and not mix the fuel and air properly. This caused them to not light on the first attempt and go into lockout sporadically. Also had a Baxi build up debris on its swirl plate and cause the same symptoms.

Ironman

There's no swirl plate on the gb142. It's not a Gianonni HX.

Ironman

Buderus approaches air to fuel adjustment by measuring the fuel pressure before and then after the negative pressure gas valve. CO is then checked and as long as it's below 400 ppm, it's okay.



Your "tech" should NOT have adjusted it any other way.

Paul Wolf

Iron, Thanks for the info. I know this doesn't help much because of the time lapsed, but the last time *I* checked a/f ratio was 1-2 years ago. The gas inlet pressure was 10.10 in h20. The gas/air ratio was at the very positive limit of spec -.04 to 0.00. (didn't have a combustion analyzer, only a digital manometer).
Before he "sent" me upstairs, I saw him check the pressure and ratio, but I couldn't see the readings or if he made any adjustments.
I'd like to find a "competent" service person, but have not had good results in my efforts. The last organization came recommended from a couple of people whose opinions I respect. Maybe they just sent a not-so-knowledgeable tech.
Trial and error (both in parts, and in service organizations) can get very expensive. I don't mind paying for either, but I would like to find a competent person that knows how these boilers operate, is a good troubleshooter and won't just keep throwing parts at it until it's fixed.
Yes, as a troubleshooter myself, I realize intermittent issues are the hardest to find, especially if you can't reliably reproduce a "pattern of failure"....

mattmia2

A combustion analyzer isn't that expensive...(although it needs to be calibrated periodically, once a year is recommended, probably could extend that a bit if you only use it once or twice a year to set verify your own equipment)
Mixture that is off a little may not light reliably.