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Antique Cast Iron Boiler Information Needed

gksmithgksmith Member Posts: 1
I need information to help me deal with my antique cast iron hot water heat boiler.  I do not know if this is the right forum or the right thread, but at least it is an attempt.  I have a Thatcher cast iron boiler in my house, built in 1922.  It was originally coal and now converted to natural gas.  It now has a Republic Gas Heating System conversion, Model A-2, with a Republic Safety Pilot, Model P2, and a Honeywell Electric Gas Valve Type V155A2C9. 

I have lived in the house since 1987 and have had absolutely no problems with the unit.  But, I know that nothing can last forever.  My gas company says it is probably one of the last in my town of 23,000 people!  But, what will go wrong?  What do I look for?  Are any parts available?  Can it be re-converted with a new conversion system?

People say I should convert to a new boiler, but I am very satisfied with the efficiency of what I have.  I keep detailed weather records and compare my natural gas consumption to Heating Degree Days per square foot and according to other information on the Web, I am in the ballpark of expecations, with mine being 10.5 BTUs/HDD/SqFt.  According to my calculations, I would have to have high enough efficiency increase to decrease my fuel consumption by 40% to just pay for the interest on a new boiler.  And that does not touch the capital expense of the boiler nor the cost of asbestos removal, etc.  But, I do not like the thought of being without heat in the middle of winter!

Any help, advice, and comments you have would be greatly appreciated!  Are there other sources of information I can tap into, too!  Thanks!!


  • Those old boilers

    are pretty simple with large waterways and no safety string, but you will have to live in fear of no heat because one day, your boiler will give up the ghost.

    You can always find replacement parts for the gas valve and pilot; maybe even the burner as well.  But nothing for the boiler itself if it starts to leak.
    Often wrong, never in doubt.
  • SWEISWEI Member Posts: 7,356
    40 percent

    is not unreasonable given the age of the beast.  ODR will provide increased comfort as well.  What did you factor for annual fuel cost increases?
  • nicholas bonham-carternicholas bonham-carter Member Posts: 6,540
    1922 boiler

    I would start by doing a heat loss survey, using the slantfin calculator. Then compare that figure for the required btu's with the input of your present boiler. You may find the old boiler to be greatly over-sized.

    A new replacement such as the lochinvar solution would have the outdoor reset capabilities which contributes greatly to comfort, and efficiency, as SW said.

    If your system has the large radiators of an old gravity system, then a mod-con would work well but cost a bit more upfront.

    You will then be able to make a quicker decision when the old one bites the rust, by having done this research.--NBC
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