Problems with CF1400 Beckett burners tripping

Luc

We have two boilers with CF1400 Beckett burners.



Before doing the annual service call last week, we had some problems with one of the burner tripping everyday or so. When the service man came to clean the boilers, he found that there was a really bad combustion in the burners and the boilers. The electrodes and flat plate, on the nozzle line assembly, were dark black with crust on the flat plate. He cleaned the the nozzle asssembly and replaced the nozzle. Then, he checked all the setting and did some reajustment. With the combustion test we could seen that there was too much draft in the chimney.



Now we have problems with both the burners tripping everyday or so. Just want to have your input on what might be the problem. Any idea on what might be tripping the boilers? Could it be to much draft in the chimney?



As for for the bad combustion and excessive draft, this might be due to the changes that we made on the chimney over a year(June 2008) ago when we replaced an old water heater by two new ones. There was a draft control on the old water heater. The two new water heater each have their draft control at the exit of the heater. Other then the draft control on the water heater, there is no other draft control on the chimney. The two boilers and water heaters are on the same chimney. They connect to a main horizontal chimney which then connect to the vertical stack. The boilers are closer to the vertical stack while the water heaters are farther away.



Thanks for the input,

luc

Paul Fredricks_3

I

am not familiar with the burner, but too much draft can pull the flame off the head. 

Ed N.Y.C.

LUC

What boilers are they in.My guess is pressure fired going by firing rate of burner. If so you must close damper at soke hood till you have a positive .10 at least,in some boilers as hige as plus .25 Hope this helps  ED

Luc

Thanks Ed for replying.

If I understand correctly, you think that there is too much pressure during the burner startup and that we need to reduce the draft.



The burners are installed on Freco boilers. The burners are have low/high firing rate. We have nozzles of 6.5 GPH. We don't have any dampers on the boilers. I did not measure the size of the flue pipe out of the boiler but it must be about 10 to 12''.

Edward A. (Ed) Carey_3

Multiple boilers and draft

Luc,

Please see the link below that shows the proper draft stabilization of multiple boiler installations.



[url=http://www.fieldcontrols.com/draftcontrol.php]http://www.fieldcontrols.com/draftcontrol.php



Ed carey

Edward A. (Ed) Carey_3

Follow up to Ed N.Y.C. post

Luc,



Ed may be correct in that your boilers are positive pressure.



However please be absolutely sure that your boilers AND your burners are designed and listed for positive pressure applications, before you try to operate them as such.



If they are designed and listed for positive pressure, then set up combustion,  venting, draft over fire & chimney draft  EXACTLY as the manufacturer recommends.



Many positive pressure boilers are positive to the manual damper at the breach, and thereafter require negative draft and draft stabilization like any negative draft boiler.



The chimney connector and chimney are usually never positive pressure. You normally would never have positive pressure past the breach of the boiler unless you have a direct vent appliance that is listed as such. 



I think that it is highly unlikely that you have a direct vent appliance of that size.  



Good luck,

Ed Carey

Edward A. (Ed) Carey_3

One more for Luc

Luc,

A manual damper at the breach of the boiler to generate positive draft over the fire, and a barometric draft damper such as a Field RC, are completely different items, and are used for different purposes.



Do not try to control the negative draft in the chimney only with the manual draft damper in the breach.

And do not try to generate positive pressure over the fire in the boiler only my manipulating a barometric draft damper in the chimney connector pipe.  



One more thing, at this point if you do not clearly understand what I am talking about, you should hire a professional to review your installation and correct any problems.



It may be a lot cheaper in the long run, as you can cause damage to a boiler quickly if you mis-adjust it relative to these issues.



Good luck,



Ed Carey

Ed N.Y.C.

Ed

I couldn't say it any better so I will not.  ED N.Y.C.

Luc

Thanks to both Ed for the reply.

The service man came at the beginnig of the week. We increased the pressure on the nozzle for the low fire. It was too low and it could have caused some of the tripping problems. We also installed a barometric draft regulator on the flue pipe, at the exit of each boiler, just before it connects to the main horizontal connector.



Before the draft regulators were installed we had draft measurement of around -0.22 "WC at the breach of the boilers. With the draft regulators installed, we have -0.01 to -0.08 "WC at the breach of the boilers. The draft seems to vary.



With this much draft the chimney seems really oversized. It is about 42 feet high with a diameter of 14''. Is there anything that can be installed on the main horizontal connector or on the stack to reduce the draft?



Luc