noisy boiler

Ron M_2

I have a hot water baseboard, gas fired boiler. About 3-4 minutes after the burner starts I get a "cooking" sound at the boiler. The sound remains the same no matter how long the burner is on. After the burner shuts off, the sound stops in about 3 seconds. The water temperature does not change the sound, whether it is low (100 degrees) or at the highest (180 degrees). The pressure does not change it. Set at 12-14 lbs, tried raising to 20 lbs, it did not change the sound. Circulator is running, flow is good (radiator loop heats normally, heats house normally)
Boiler is about 5 years old, this noise only started with this heating season. There is no air in the system.(when it had air I heard "gurgling" in the baseboard)
Any suggestions?

lee_7

is noise similar to old fashioned popcorn popping? It could have "mud" in baseboard and "crackles" when heated.

Ron M_2

noisy boiler

Good description of the sound...it does sound like popcorn.
I drained water from the bottom drain. I got a little blackish water resembling pepper and then just clear water. Ran it for about two minutes. I did not make any difference in the noise.

lee_7

how old is boiler? The boiler might need to be drained and thoroughly flushed. there is a product, i have not had to use in some time, i think it was boiler king, to help remove mud. The air in mud on bottom of boiler perculates out as it heats. Do you have a domestic coil on this boiler?

Ron M_2

Thanks for your reply. The boiler is 5 years old. It does not have a domestic coil.
I did not drain the boiler completly. I opened the bottom drain on the boiler allowing the makeup water feed valve to replenish the drained water. I did this with the loop closed, so all of the flow had to go through the boiler. It is not a very strong flow through the pressure regulator.
Could I connect a garden hose to connection used to purge the loop, keeping the loop closed it would flow through the boiler with a stronger flow?
Any other suggestions?
I will do a search for the flushing product you mentioned.

lee_7

Empty boiler completey, and flush with as much pressure as you can. a garden hose will work. Put in the the drain located at bottom of boiler. this should help lossen mud.

Ron M_2

Thanks. I'll try it this week end.