Insulating return pipes

DanHolohan

Water absorbs carbon dioxide as it cools in a steam system, forming carbonic acid, which will damage the returns. This is more an issue in a gravity-return system than in a pumped return system because the water lays in the pipes all the time.

With a two-pipe system that has traps and a feed pump, you have to be concerned about the temperature of the condensate hitting the pump because that pump's receiver is open to atmosphere. If the water is too hot, the pump will cavitate. If this is the case, don't insulate the returns.

J Roy

Insulating return lines of 1 pipe steam system

I have read that you should not insulate the return lines of a steam system because it hinders the condensate process, and hot water is not good for the pumps in the return section of the boiler. Are these claims correct, or should I insulate the returns as well?

Tim_16

Return Pipe Insulation

If the water temperature is coming back to hot just remove some insulation. If you have a vacuum return I recommend removing the insulation. In the past what we have done to drop the temperature of the return is add some steel fin tubing.

J Roy

Thanks Dan, I have a one-pipe system, so I am assuming that I should insulate the return pipes as well. One more question - what is the benefit of insulating the return pipes on a one-pipe system?

P.S. I just got your first book "So you got steam heat" last week - it was a great read!