Oil to Gas Boiler Replacement Sizing Issue

RunningOnVaporsInNJ

Hi,

I have a Warren-Webster Type "R" Vapor System connected to mostly Crane 23" X 8" tube radiator sections, which were all designed for oil heat when the house was built in 1934.  The present boiler is a WM P-466-E oil burner connected to a 2” riser and header that has since installation in 1979 been under run with a 1.0 GPH nozzle to output 115,200 gross Btuhs. (A WM engineer assuming the boiler runs at optimal performance provided the 115,200 gross Btuhs.)  When using the 1.25 nozzle suggested for a 466 boiler, the boiler gets the whole house vibrating like an earthquake hit it.  I have successfully used the information from this site and patents posted on the Warren-Webster return trap to correct a number of bad maintenance issues and understand the good maintenance choices.  

For some time I have been looking into switching from Oil to Natural Gas.  The recent failure of our water heater caused us to act now.

The reason for this post is to get some help with different boiler size estimates that I recently received for the house that include a WM EG-45 with 125,000 Btuh gross output, and two Burnham models IN-5 and IN-6 with 115,000 and 144,000 Btuh gross output, respectively.  I am presently leaning toward the Burnham boiler as the 2” riser and header minimums avoid asbestos abatement issues at the header.

My issue is that based on the EDR book, the radiator system works out to 415 sq ft or 99,744 net Btuhs or 132,660 gross Btuhs.  I now have Dan Holohan’s two steam heat books and his EDR book, I get 415 to 421 sq. ft. depending upon the estimate for one weird radiator at the entranceway.  Thus, based upon the EDR of the radiators, two of the estimates and my current boiler would appear undersized for the job.

The current boiler is run with a pressuretrol setting of 8 oz and uses a programmable one-zone thermostat that operates at night at 64F and at daytime at 69F.  On the coldest days it takes about 90 minutes before sunrise to bring the house heat up 5 degrees from 64F to 69F.

Based on the EDR alone it would seem that the IN-6 is the only choice.  However, the current boiler has run successfully and quietly at lower Btuhs and two estimates have come back with smaller boilers.  Is there another consideration that I am missing?

Thanks in Advance,

Don

The Steam Whisperer (Formerly Boilerpro)

Take a look

at the other current topic on replacing a steam boiler.   If your system is the Webster system with orificed valves, downsizing the boiler should be no problem.  I installed a staged steam heating plant in a large Warren Webster system last fall that only runs on one boiler in warmer weather, with the second coming on in really cold weather.   The overall boiler capacity was sized to the home heat loss, not radiation and the owner balanced the system of about 60 radiators using the radiator supply valves.  This system was the earlier non-orificed supply valve Warren Webster system... the later system had orifices that would balance the steam supply when running at lower boiler outputs. 

This idea of "undersizing " steam boilers defies current conventional wisdom, but if you dig deep enough into steam history, you will see that it was used successfully then and if you search today, it is also being used quite successfully on a large scale.

Steamhead

All of the boilers you mentioned

are atmospheric types, which are not the best you can get in that size.



With the amount of radiation you have, you have two good choices: the Smith G8 and Slanf/Fin Intrepid series. These are wet-base boilers that use powered burners. Mostly they are used for oil firing, but are approved for use with powered gas burners such as the Carlin EZ-Gas.



A wet-base boiler surrounds the flame with cast-iron having water on the other side. This picks up more heat from the flame. The usual atmospheric boiler has the burners completely below the cast-iron so it loses more heat from the base. Not surprisingly, the government-issued AFUE ratings don't consider this a loss since it goes into the basement. My position is if it doesn't go to the radiators, it should be considered a loss.



Also, the power burner can produce a clean flame with less excess air. This means less heat escapes up the chimney. Together, these differences mean the wet-base boiler has a thermal efficiency (BTUs in to BTUs out) 6-7% better than the atmospheric. You can see why gas companies love atmospheric boilers.



Here are pics of these boilers.

RunningOnVaporsInNJ

Thanks for ... another perspective

I took a look at your earlier post before submitting this one and have read up the metering orifice which may exist in the Webster radiator supply valves.  This may explain why my current oil burning WM 466 purrs like a kitten when run with a 1.0 nozzle and rattles the house like an earthquake when a 1.25 nozzle is used.  Although my Webster valves look similar to the Webster literature posted on heatinghelp.com, is there any way to detect a metered orifice other than disassembling the valve?  Thanks again. Don

RunningOnVaporsInNJ

Maintenance Support Limited for Burner Conversions

Thank you for the information, I had read your suggestions for the Slant/ Fin and Smith 8 on your previous posts and looked at these boilers based on your advice.  Earlier, I had even looked into a burner conversion for the WM 466 and received advice from Midco on using their burners in my current burner.  Unfortunately, the only steam experts in my area that I felt comfortable with my system would not maintain my oil boiler once I converted to NG except for one and he has now retired.  Further complicating these options is that when we returned from our August vacation to find water and oil flowing from our oil water heater, I pulled out plans I had for doing a conversion from a year ago when I knew a lot less than today.  My retired steam pro recommended using the gas company to replace our water heater first as they under charge for the chimney liners.  (It is another story why indirect hot water was not considered.) Two weeks ago when the gas company put in a NG water heater, they also put in an AL chimney liner spec'd for an atmospheric boiler.   It is my understanding that the burner guns for the wet based boilers require a sheet steel liner.  At this point, I believe the cost of replacing the liner would be greater than the savings in fuel.   Finally, I believe both the Slant/ Fin and Smith 8 would require re-piping of the riser and header and consequently asbestos abatement, which I am told I may avoid with the Burnham In-5 or In-6.

Too bad your not a little closer.

Thanks,

Don

Steamhead

That's the gas company for you

they put in a liner that only works for gas.



The difference between stainless and aluminum is that aluminum is for gas only, whereas SS can be used with oil or gas. Also, AL can rot out if used in a chimney that had an oil burner in it, according to our chimney contractor.



It makes no difference what type of burner is used with an AL liner as long as it's gas. So a power burner will work fine with an AL liner.



It is typical for a fuel supplier to push equipment that is not the most efficient. These companies make their money from fuel sales. If that sounds like a conflict of interest..... well, we have a customer who is a lawyer, and according to him it is.

The Steam Whisperer (Formerly Boilerpro)

Not sure....

I haven't run into the orifice Webster system yet.  It is pretty simply to just remove the union nuts on the supply and return to a small rad and move it out of the way to peer inside the valve.  The Lost Art part 2 has info on both the pre and post orifice systems.



Where are you located?

RunningOnVaporsInNJ

My Fault ...

I agree the gas company makes decisions that benefit their bottom line, but here the fault is mine.  They came the same day we called with water still on the floor.  I gave them the specs from my previous steam pro (now retired) and they built the liner to order.  If somewhere in those plans we had been considering to continue to use the oil burner, I believe they would have installed a SS liner.

Thanks,

Don

RunningOnVaporsInNJ

Understood ...

Based upon these posts and other thread posts, you have helped me narrow my decision as to who to trust with this job.  Thanks, Don 

Larry49

Slant Fin Steam Boiler

Regarding this image:  http://www.heatinghelp.com/images/posts/3589/resize_Dixon%20boiler%20007s.JPG







How did you obtain this boiler?  Did you purchase the boiler separately

from the burner or did the boiler and burner come together as a unit? 

Why do you use a barometric damper instead of a draft hood in this

installation?  I noticed a control on the left side of the boiler

attached to the

equalizer line.  What is its function and who is the manufacturer?



I am also posting this question as a new post:  http://www.heatinghelp.com/forum-thread/144438/Slant-Fin-Steam-Boiler/

JohnNY

RunningOnVapor,

Can I ask where you are located?

RunningOnVaporsInNJ

Re: RunningOnVapor,

I am located in Mercer County, NJ.  To complete this thread, I eventually had a Burnham IN6 installed in November 2010.  With the NG, the system runs so quiet that the rattling of the vacuum valve ball is the only indicator that the boiler is running.  My heating bill subsequently dropped by 60%.  The boiler runs on such small amounts of electricity, that my sump pump generator was able to run it during our extended power losses from the freak Halloween snow storm of 2011 and Hurricane Sandy in 2012.  My wife was very pleased with that feature.

Regards,

Don

Larry49

where I am located

Hi, I am located in central Pennsylvania