bad burners???

Paul S_3

hey everyone....i went to a no heat call on a KENMORE (DUNKIRK) steam boiler it was installed by a contractor from SEARS....customer was fed up and called my company....besides the horrible steam piping that i would have to fix once i fix this problem i found the boiler carbonized severely with black soot(gas fired)on the right two sections...rollout was tripped ....so i cleaned the whole boiler like i always do and did a CO test in flue ...i got the levels down to 18PPM from 3800PPM....also did a combustion test O2=7 CO2=12 STACK TEMP= 375F DRAFT= -.03.....the problem is with the boiler cleaned im still getting a slight rollout at those sections and the gas is igniting right at the orifice at the gas manifold....gas pressure coming IN with all appliances on is 6" W.C.....and OUT is 3.5" W.C....can the burners be bad???boiler is three weeks old....and when i switch burners it happens with any burner??

PAUL S

JStar

Burners

Check the orifices. They might be slightly deformed. You can ream them out a little, but would be best to replace. York furnaces had a recall for the exact problem.

unclejohn

Is it

A slow opening gas valve? Is the pilot burner in the right place? Is there any air adjustment on the burners?

Tim McElwain

You have something wrong

with the combustion analyzers readings. The CO2 12 is impossible as that is the ultimate CO2 for natural gas. The 7% O2 has to match up to the CO2 so with a 7% O2 you would have around 8% CO2. What analyzer did you use to get 3800 PPM on CO?



You are experiencing "FLASHBACK" which can be corrected by adjusting the primary air until it stops. Typically you want to close up the air shutters. If there are no air shutters on the burners try making some and clamp them on to the burners and see if that helps. The other thing is to make sure the burners are for natural gas and not LP, contact the manufacturer.

Paul S_3

bacharach

0024 8515 FYRITE INSIGHT PLUS....thats the combustion analyzer i have....maybe i wrote wrong readings....how would i make air shutters if i dont have any??

PAUL S

Tim McElwain

Send a picture

of the burners and I will try to explain how to make air shutters

Jim Davis_3

Roll-out

Roll out can be caused by burner position.  Many manufacturers build their equipment so it can be converted to propane which requires downhill burners whereas natural gas requires uphill burners if in fact they are ribbon burners.  Raising burners does help this, however when it is isolated to one or two burners then venting is more of an issue. 

You have more than one burner but only one set of combustion readings.  Each burner must be tested individually if the drafthood is rectangular.  If it is round and on top then the drafthood must be tested on the left, center and right.

Delayed ignition usually doesn't cause severe sooting.  You need to monitor the flue gas readings for the whole cycle and make sure there is no increase in the CO during the whole cycle.

Charlie from wmass

Did you check the chimney?

Was a liner installed? Is the chimney blocked?

Paul S_3

no liner

Very old brick chimney...with no liner...I'm getting very good draft though...could pilot position cause this?....

Joseph_4

Did You Power wash it?

You said the boiler was only 3 weeks old. is there constuction going on there? I had a similar problem.

joe