No math please

Booj

I know it might not be possible to answer this question absolutely correctly without math but I just need a bit of advice on the sizing of my main steam pipe. I've got a two story house with seven radiators. I'm correcting a pitch problem that created the most sensational water hammer that this house has ever experienced. as entertaining as it has been over the last couple of years, I don't think it would survive over another winter.

The main itself pitched down to an elbow then back up.

Here's the question. My main is 2 1/2" pipe (which I've heard may be too big) and at the point I need to correct the pitch I've already fed three of the radiators so I want to use an eccentric reducer to take the size down either to a 2" or even a 1 1/2" main for the last four radiators. Does seem like a reasonable plan?

Charlie from wmass

you can but it may lead to cold radiators.

But in all seriousness without the square footage it is like saying what size pipe do I need to fill that pool in an hour with out knowing the dimensions of that pool. Seldom did a person thread 2 1/2" iron when they could have used 2". I have seldom found over sized steam pipes unless radiators were removed from a section.

Booj

Okay, a little math

Thanks Charlie,

I live in a 136 year old 2 story house with high ceilings and a total of about 1500 square feet and I guess what I'm wondering is what risk do I take by reducing the size of the main either to 2" or 1 1/2". It's a loop design and it's about a 16' run to reach the next riser pipe. It operates on very low pressure now and the heat only reaches the last radiator if I crank up the thermostat to about 78. Remember, I only have 4 more radiators to reach after I downsize. Any thoughts on this will be helpful.

Thanks again

Booj

Charlie from wmass

If it is taking that long

You have a venting issue. The math you need is what size are the radiators that are being supplied. If you do not have large enough pipes the steam and condensate will be fighting for room. this means water hammer and cold radiators. More than just steam goes through those pipes.

Booj

Here's to hoping

Thanks once more Charlie.

I'm hoping that correcting the pitch will fix my condensate problem. That's where it hammers. It's amazing how much water is created by the condensation trying to run back to the boiler. I mean gallons. Now, I see what you mean about pipe size but if the blockage created by the pitch is corrected will there still an issue going to 2" or 1 1/2". It's two large radiator and two small ones. And Charlie, I'm worried about your venting comment. If I could pick your brain just a little bit more could you elaborate on that. Thanks Again.

Booj