Have a 20 yr old Burnham cast iron boiler. Tankless coil needs replacement. Service man said because of excessive rust may not be able to mount new coil.What are my options, besides a new boiler,

why does it need to be replaced?
if it is not producing enough hot water you can add a storage tank.
what happens is that a bronze circulator circulates the hot water from your coil into a storage tank.
the tank is called an aqua booster.
this is one brand..
[www.vaughncorp.com]
this is the cheapest way out.
another option is to add an indirect water heater. this is a good way to go but costs big bucks..

Its still producing plenty of hot water, but serviceman said when it does go they wont be able to attach new coil to boiler because of excessive rust on face plate of existing coil, in other words they will have to break bolts and re drill and tap threads. But there may not be enough meat left on boiler to do that.

"but serviceman said when it does go"..
what does that mean?
in other words, define "go"..

When the bolts break off, I just drill thru the remaining stud and remove them. No need to drill into the boiler or retap anything.

If it begins leaking into boiler can cause excessive pressure. Mainly concern was rust damage to boiler base where coil bolts on. Said bolts would have to be drilled out and retapped. Just dont know what damage there is until its taken out. Dont know if welding cover plate over coil opening is an option, then getting seperate on demand heater.

Maybe worrying about nothing, but it sounded like its possible for base that coil bolts to can be so rusted that its impossible to retap.

i have only seen one coil develop a pinhole and overpressurize a boiler.
it is not a very common occurance.
i have however seen a few rusting tankless plates that caused damage.
there can be slight damage to the flat surface on the boiler caused by rust but that takes a very long time and does not just all of a sudden start gushing.
worse comes to worse, you inject a little boiler sealing compound into the system and seal up the leaks from the inside. this will buy you a few more years.
i have never seen a plate welded over the tankless opening. welding cast iron is something not all welders are capable of.
if you want to post a picture, i'll be happy to give you my personal opinion.

juuuust a possibility:


pressure down system

remove and replace bolts ONE AT A TIME

~ use an impact gun set LOW and a lot of patience when removing each bolt

if it 'snaps' - use an extractor tool/system to remove 'stud'


use never-seez on replacement bolt


at one per day in your spare time ?!

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Thanks for all the advice, too bad I'm not a plumber. Have to rely on heating dealer. Don't want to get screwed by someone telling me they can't replace it and need a new boiler.



Edited 1 times.

my way is too costly unless you DIY

I can't help further unless I see the actual job

best of luck

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638