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Gas boiler expansion tank question?

I have an older 1950's model American Standard gas boiler. Going to the expansion tank is a thin gauge copper pipe divided into 3 sections with valves between each section. When the boiler is running the entire copper pipe leading to the expansion tank gets very hot. After the boiler stops about 10 minutes later the 2 sections of copper pipe closest to the expansion tank get cool. The section of copper pipe furthest away from the expansion tank which runs directly into the boiler pipes stays very hot. Is this normal? Also, if I drop the temperature in the house from 68 to 63 will the pressure needed to run the boiler drop? At 68 degree the cold pressure is around 14, hot around 17-18. Thank you!

1 Answer

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  • Anonymous
    7 years ago

    The copper pipe running to the expansion tank will get hot. AS water is heated, it expands, and it is this expansion that is running up the tank and reducing the build up of hot water in the boiler. When the boiler is off, this pipe will cool down. It is a normal thing for this type of boiler. The three pipes connected to the pipe are take offs for other things such as a Bath tub, hot water for the washbasin, or the kitchen taps. They are valved for maintenance purposes, so that the hot water can be shut off in case of any plumbing repairs. This is a normal installation and all in order.

    Source(s): PLumber UK. THe pressure in the boiler will be fine if you drop the temperature. The circulating pump will keep the preeure constant.
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