Everything Updated But......

rhw1

So it's all repaired but one heater in one room sounds like a ball pein hammer is hitting it for several long minutes when the heats turned up. The riser runs up two floors on an outside uninsulated wall. This is a one pipe system and the radiator has been lifted on one side for proper return flow. Bottle plastic down the riser is not helping. Might be able to use that Great Stuff insulation to hit a portion of the pipe. Any thoughts?

ethicalpaul

There is likely a valley holding condensate water. The steam hits it and collapses. After awhile the pool of water gets warm enough that it doesn’t make the steam collapse and the hammer stops.

It’s likely a short horizontal section under that floor.

try lifting both sides of the radiator a half inch per day to see if it stops

rhw1

Thank you. I will start lifting from the supply side as well.