boiler re use assistance


Old 09-11-10, 06:45 PM
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Smile boiler re use assistance

We have located a good brand of boiler that was used for 12 years and wish to install in our home First, it needs to be pressure tested as it was known to leak at the piping connected to the boiler We need to remove the nipples screwed into the main boiler -- both the upper and lower We understand that heating up the outer part of a threaded joint will expand and make removal easier So question #1 is can we heat with a blow torch the actual cast boiler around where the nipples are threaded in? or will this cause problems doing this?

Is seems most plumbers in our area do not want to get involved with a used boiler even though we believe it to be respected high quality brand and only used for 12 years

So we are on our own to at least do a pressure test
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Old 09-11-10, 08:21 PM
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Have you tried getting the nipples out with a wrench? If it is rusted, try soaking it with PB Blaster.
Old 09-12-10, 01:41 AM
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I'm assuming this is a cast iron sectional boiler and if so I don't blame the plumbers a bit for not wanting to touch it. Moving a previously used cast iron sectional is just asking for trouble.

I would STRONGLY urge you to NOT attempt to remove any nipple from the boiler. Hopefully the previous installation didn't use reducing bushings in the boiler tappings. Trying to remove a nipple from cast iron could cause the threads to come out with the nipple or even crack the boiler. If the nipples have been sawn off where the boiler connected to the old system then hopefully you have enough nipple left that you can use a ratchet pipe threader to cut new threads on the nipples. If you have threads on the outboard ends then use pipe caps to close them.

Be VERY careful when you pressure test this unit. Do not go over one and one-half times the placarded operating pressure, which is probably 30 psi so 45 psi maximum. You really need to use warm water (100 degrees or better) or else you will likely have leaks at the push nipples between the sections, maybe even then.

I hope you didn't pay much for this boiler. If it was a used steel boiler I'd say okay but a cast iron one is just asking for trouble. I hate cast iron boilers.
Old 09-12-10, 06:33 AM
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It seems the situation can be paraphrased as

"We have a good brand of 12 year old leaky boiler".


If nothing seems wrong with that, then keep reading it until it does.

A well-installed, properly-sized el-cheapo new boiler will perform better and more reliably than what you have described.

Do a heat loss for the building to figure out what size boiler you actually need. There are threads around here that describe how/software/etc., starting with the sticky at the top of the forum:

Then start shopping for installers who know what they're doing. A good place to start would be with any of the plumber who wouldn't touch this old leaking boiler.
Old 09-12-10, 07:51 AM
Join Date: Mar 2009
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used boiler

Somebody got rid of that boiler for a reason. It's probably a pin boiler, known as a single pass boiler, very ineffecient, and a bear to clean every little space. A new 3 pass boiler properly sized will pay for itself very quickly.

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