Boiler turns off

daveamir

Hi guys when my steam boiler turns off After about 5 minutes after the heating cycle I hear a banging sound in my pipes it only happens once wondering if anyone knew what that might be thanks gits

Jamie Hall

After that much time off, it doesn't seem so likely that it is a hammer. My first reaction would be a bang caused by the pipes contracting as they cool. Can you locate it at all?

Fred

What kind of hangers are your steam mains supported by (steel hangers against the iron pipe)? I'm wondering if a main might be contracting, as Jamie said, and dragging a hanger along with it until it reaches a point where it springs back into its proper position. If that's what's happening, slip a strip of plastic milk carton between the hanger and the pipe.

daveamir

Will a pic help can this cause a problem

Fred

Yes, post a picture. The noise is more of an aggravation than anything else, if it is, in fact, a hanger contact issue.

daveamir

Ok I will post when I get home thanks

daveamir

Here are the pics the rest of the main is covered with little openings in ceiling so it can heat the basement

acwagner

Another possibility is the lack of hangers. On my system, I had a similar problem because the run out pipe to a radiator was pretty long (10 feet or so) and was completely unsupported except by the radiator connection. It would make a sound similar to what you are describing during cool down. I added a support and it went away.

Have you been able to determine generally where the noise is coming from?

If not, after shutdown, try walking around all the radiators. Your weight on the floor might be enough to trigger the noise. Or you could push down on the radiator valve a little. That's how I discovered the location of mine.

mikeg2015

I have one too. I suspect it's a hanger that's dropped...since the floor has sagged. I probably just need to adjust the threaded rod.

FYI - I'd pretty sure the gas water heater isn't vented right. It's supposed to have a top hat for secondary air. Can;t see how the boiler and water heater flues are connected, if at all.

Also, is the basement and house fairly leaky? If not, You really should have a make up air vent down there since it's semi-finished space. Keep water heater and boiler from back venting in winter when stack effect creates a negative pressure on lower levels. A powered flue damper on the boiler isn't a bad option either. A lot of hot air goes out the chimney between cycles. I rettrofitted one on mine it's it's a huge difference. I figure it saves around $20-40 per month in energy being wasted. Keeps the basement warmer too.

Fred

I don't see any hangers on those mains, except maybe right at the boiler where they branch off. Somebody probably took the hangers off when they put that paneling on the ceiling. That allows a lot of movement in that piping. You probably should have some hangers every ten feet or so, along those mains. That, by itself may solve the problem. Make sure when you do that that the mains are pitched properly.

STEVEusaPA

mikeg2015 said:

...FYI - I'd pretty sure the gas water heater isn't vented right. It's supposed to have a top hat for secondary air. Can;t see how the boiler and water heater flues are connected, if at all...

Neither flue pipe should be that close to combustibles (i.e. wood paneling). Also maximum length for a flue connector is 10'.

daveamir

Thanks guys I think I will have a plumber take a look make sure all is safe thank guys