Noise Coming From Cast Iron Boiler (video provided)

stupidhomeowner

Hey there guys, just got a strange noise coming from my cast iron dunkirk boiler from around 95'. only makes noise when i call for heat. cant pinpoint exactly where except from inside the boiler. I took a video and posted the link below and you can hear around the 20sec mark when i get close to the supply pipe coming off the boiler it picked up the noise more in that area. im baffled though.

what do you guys think? is it serious?

https://youtube.com/shorts/O4JtQM8rSd8?feature=share

EdTheHeaterMan

Dunkirk boiler from 95' ? ? ? You mean 1995 so the boiler is 28 years old?

What you are hearing is called Kettling The water is boiling at the cast iron closest to the flame then when the steam bubbles move up to the water that is further from the flame, it implodes back into water. This happens when the water moves too slow thru the boiler. Was the circulator pump replaced recently?

You may have a blockage in the old piping somewhere. Can we see a picture of the pipes around the boiler?

stupidhomeowner

so i have 3 pumps, one for each zone and one zone is closed off(the basement zone). i did replace the other two zone pumps with pumps that have a 3 speed control on them which are all set to the middle position. i guess that would be the only change in the system. maybe turn them to the highest setting?

EdTheHeaterMan

stupidhomeowner said:

so i have 3 pumps, one for each zone and one zone is closed off(the basement zone). i did replace the other two zone pumps with pumps that have a 3 speed control on them which are all set to the middle position. i guess that would be the only change in the system. maybe turn them to the highest setting?

What is the possibility that one of the pumps is installed backwards? That is why I wanted the photos of the pumps and pipes.

stupidhomeowner

here are the pictures you requested. hope it helps, otherwise i can take better ones for you. the center pump is the old bell and goset which is not in use at the moment. the two outside pumps are the new ones.

EdTheHeaterMan

The pumps look like they are in the correct direction.
Try the higher speed.

If that does not help, then there may be a blockage in the return pipe. The pipes you just worked on when you changed the pumps.

How high does the water temperature on the gauge get during a heating cycle if only one zone is operating?

hot_rod

hard water can scale them and cause percolation. The sound you hear in an old scaled tea kettle. Has water been added, a leak in the system anywhere?

You can add a chemical that loosens scale and keeps it in suspension.

If it is not a mechanical issue, might try a cleaner.

stupidhomeowner

EdTheHeaterMan said:

The pumps look like they are in the correct direction.
Try the higher speed.

If that does not help, then there may be a blockage in the return pipe. The pipes you just worked on when you changed the pumps.

How high does the water temperature on the gauge get during a heating cycle if only one zone is operating?

so the temp gets to 180f.

hot_rod said:

hard water can scale them and cause percolation. The sound you hear in an old scaled tea kettle. Has water been added, a leak in the system anywhere?

You can add a chemical that loosens scale and keeps it in suspension.

If it is not a mechanical issue, might try a cleaner.

god i hope there isn't a leak anywhere, no leak in the boiler room though.

leonz

If there was a leak in your system you would know.

Is there a low water cut off switch on this boiler? If not, you have to have one.

If you are concerned about the kettling noise you can simply lower the low limit temperature and the high limit temperature on your aquastat to 140 degrees Fahrenheit low limit and 160 degrees high limit AND lower all the circulators to speed 1that would help a great deal.

If you could upload a few more pictures of your boilers plumbing that would help a lot.

You can always buy a can of Furnox water treatment and treat your water that way by following the directions on the can and connecting it to the boiler drain in your system.

Kickstand55

Might be a good idea to have the water analyzed for minerals, pH and chlorides.
As mentioned above, add chemicals the minimize the effects.
Supplying hot water to the feed line can help as well as a descaling cartridge.