Banging pipes at specific times

JodiMe

Hi. My pipes and system are generally very quiet but occasionally in the morning, when coming up to day time temp, we get some major banging in them.

A bit before we usually get out of bed, we set it from overnight temp (66) to 68 so we can muster the strength to get out of our warm covers. Then an hour later, as we are getting up and at em, we have it go up to 69. The banging almost always seems to happen just as we start that second cycle. 

Anyone know why this could be? It doesn’t seem to happen at any other time.

Jamie Hall

hot water? Steam?

JodiMe

Steam

Jamie Hall

The long run from 66 to 68 is producing a lot of condensate -- and somewhere... hard to say where... some of it is hanging up long enough so that when the heat comes back on, it bangs. Question is... where?

JodiMe

That makes sense. Maybe we will play with the timing settings a little and see if we can get in the sweet spot where it doesn’t happen. It’s not every morning but even once in a while it’s concerning/annoying.

bburd

First, figure out where the banging is coming from. Then check pipe pitch to ensure that condensate can drain freely. 

If you have fast radiator vents in that part of the system, slowing them down will reduce the rate of condensate generation.

Fred

Look for a pipe or pipes that have lost their pitch or have a sag in them and correct the pitch or sag. If the banging sounds like it is coming from under a floor board, near a radiator, try to raise that end of the radiator to get the pitch back, in the pipe under the floor board, and then re-pitch the radiator.

JodiMe

Thanks for the help. I know exactly where it’s coming from so I’ll take a look. We do have a fast vent on that specific radiator since it’s at the opposite and of the house from the boiler and is pretty sizable. 

bburd

Also be sure the radiator shutoff valve is fully open.

Sometimes the valve disc becomes detached from the stem; then the steam and condensate fight each other and can produce gurgling and/or water hammer.

JodiMe

How do I check this? 

JodiMe

Oh, never mind. I’m slow on the uptake today! I’ll double check those...