Buderus G115 misconfiguration

Fountain38

I have a Buderus G115/4 installed with a Carlin EZ burner and Field Controls power ventilation system.  I am the new owner of the home, and the system was installed in 2002.  The system has been problematic.  System was originally installed as direct vent, owner reconfigured to power vent on a recommendation from a friend following a puff back.  System maintenance was done Sept 2009.  November 27th system was in safety mode, and an oil relay on the side of the burner was replaced to repair.  I scheduled maintenance for Friday December 10th.  Buderus Boiler and side of the house was covered in soot upon arrival.  Another puff back had occurred.  System maintenance was done, boiler was cleaned and vacuumed.  Oil company is suggesting I replace Carlin with Riello.  Chimney is really not an option.  What else can I do?

Ironman

Combustion Analysis

Do you have the results of a combustion analysis?

Fountain38

Results of Combustion Analysis

I am sorry I do not have this.  Once operational after the servicing of the unit on December 1oth, The technician stuck a large syringe like device with a bicycle pump handle in a hole on the vent pipe.  He pulled on the handle several times and the white circular cloth inside the device was clean.  He indicated the unit was burning clean at that point, following his servicing of the unit.  He did not mention a "combustion analysis".  Would this indicate cross contamination?

icesailor

Buderus

If the Buderus doesn't have a "rug" of refractory material in the bottom of the chamber, in my opinion, it will never run properly. Someone may make it run all right but the reractory will make it run properly and better when it is cold. It will smoke like crazy when it is cold and stop when it gets hot.

Also, what kind of oil filtering do you have? I consider two spin-on types of oil filters as the minimum for this application. The nozzle is so small that the slightest crud in the oil that gets past a single filter will clog the nozzle strainer and drop the fuel pressure after the strainer and into the nozzle orifice. As soon as the orifice pressure drops, the air/fuel ratio goes away and it will smoke.

My opinion only, for what it is worth.

Ironman

Combustion Analysis

The tech did a smoke spot test. This is only a part of combustion analysis. The fact that it's burning "clean" does not mean it's burning right. The pump pressure could be too low or the air or draft too high and it would show "clean" on the smoke test. The G115 can not be underfired or de-rated. Some one who has a digital analyzer and knows Buderus needs to service your boiler.

meplumber

Ironman is right on the money.

The Buderus G115 runs horribly in a power venter setup and doesn't run very well in a direct vent setup with the Carlin Burner and the aftermarket kit.



I have installed 50 or so of these in a direct vent setup, with the Riello DV burner with no problems.  Make sure you get the post purge control that is available. 



It is possible to dial what you have in a little better, but you have to have a digital combustion analyzer and the intelligence to understand what it is telling you.



Good Luck.

Fountain38

Should I remove power vent for a direct vent?

Following the upgrade to the Riello DV burner with post purge control, should I remove the power vent and go with an AT-4 Aerocowel and use the basement air for fresh air intake to eliminate cross-contamination?



Thanks guys for all the advice and guidance.  Greatly appreciated!