Copper Pipe Installed On Steam Boilers Is Crazy

Copper Pipe Installed On Steam Boilers Is Crazy

Copper Pipe Installed On Steam Boilers Is Crazy! Do you have steam heat? Has your steam boiler been recently replaced or repaired, was copper piping installed? There is an ongoing battle over what kind of pipe to install, some heating contractors use steel pipe, and others install the copper pipe. Industry standards specify the use of threaded steel pipe with cast-iron fittings for steam heating, no ifs, ands, or buts. Find out what copper pipe can do to your steam boiler and why steel pipe is the right choice for steam heating.


Using copper piping on steam boiler supply pipes would be a lot less labor involved, but it causes big problems. Copper pipe expands more than steel pipe. The high-temperature change in a steam system will cause copper pipe and fittings to soften and become weak. This will eventually lead to the following:

  • boiler failure
  • pipe & fitting failure
  • no heat
coppeer & steel pipe
Incorrect installation
steam boiler
Steam boiler correct installation 12-29-2016

Not just expansion

This is the second problem that copper piping will cause for a steam boiler. Copper pipe, steel and cast iron fittings are dissimilar metals. The connections where these metals meet will corrode unless dielectric unions are installed. The debris created from corrosion inside the boiler and pipe will work their way into the steam piping system causing blockages and controls to fail.

Steam return lines

steam return line
Condensate return line

Aside from the supply lines, there is one spot for copper piping on a steam heating system, and that’s the wet return lines. The reason being is the condensate water does not cause a lot of expansion and contraction because it’s cooled down. A copper wet return line will need a dielectric union, so no corrosion occurs in the steam system.

What do I do?

If you have steam heating and you’re not sure that the pipe & fitting connections are joined together properly, a simple inspection will give you peace of mind. Click to schedule a steam boiler inspection.

4 thoughts on “Copper Pipe Installed On Steam Boilers Is Crazy”

  1. We had a plumber place pipes last year for our steam heat and we trusted him and he used copper pipe. Now we are having system trouble with our heat and will need to replace the pipes again. Can we sue the original plumber?

    1. I will consult with your attorney or an attorney if you don’t have one. All I can legally tell you is that copper pipe no matter what thickness isn’t correct pipe material for steam heating supply. If the boiler near piping is wrong that too can also contribute to your problems.

  2. All I can say is Vince Marino, is beyond an expert in his field of plumbing and contracting. I’m from Massachusetts nowhere near Pittsburgh but had my oil fired steam heating system and tank less domestic hot water heater replaced because it had let go. We went with a plumber that was referred to us by a friend of the family. The plumber said they wouldn’t do a tankless hot water heater but would recommend is to go with the same oil fired steam boiler but use an indirect domestic hot water tank that runs off the steam boiler.

    After installed, our hot water was scalding hot and when just running the hot water the boiler would fire to heat our storage tank and create steam which would heat up our radiators and in turn heat the house. So after calling our installer several times to try to rectify the situation he wouldn’t answer. So I set out to find an expert opinion. This is where I found Vince Marino’s web site and thought to give him a call.

    Once on the phone with Vince even though I’m out of state and I called on a Saturday Vince answered and asked for me to send pictures of the heating and domestic hot water system. From just the pictures He was more then helpful as he said our steam heating system was installed with copper pipping which is wrong and voids Weil McLain’s warranty on the boiler it has to be back steel pipping. And he also stated that the hot water was dangerous in the way it was installed and we should have a city plumbing inspector out here immediately to inspect and correct the whole system.

    I really am at a loss for words with how Much help Vince Marino was and how he talked me through what was wrong and the people and places i needed To contact to try to rectify the situation. I am entirely grateful to how true his professional opinion is. He not only helped me out on his own time and over the phone From miles away pointed me in the direction we needed to go to fix this potentially dangerous heating system and domestic hot water install.

    I would like to thank you Vince once again for your time and your expertise on what was my plumbing nightmare. So glad I stumbled upon this web page on the internet. You were beyond helpful. And I would recommend Vince Marino to anyone who needs an expert in heating and or plumbing repairs.
    Thanks Vince!

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