Crackling Noise near waterline after Megasteam 396 installed

miner1

Its been awhile since I've reached out on this site, had to get new user name and passsword, got some good advice on this site in past so I'm reaching out again. Had my boiler replaced (hole above waterline blasting steam up vent pipe) last fall 2025, got a few quotes and was amazed at the variation in pricing. Went with a plumber who learned steam from his dad and seemed solid. Install of the Mega Steam 396 3 section went well on my single pipe system, main header piping replaced with drop header (old piping did not have drop header), piping pitched properly and installed per spec, new piping to domestic coil in boiler, wet returns not replaced. Never had any issues with water hammer or carryover with old boiler.

System ran fine at startup and for two months was quiet, It was skimmed on startup and several times over a month drawing of 2 gallons at a whack. Two months on it started to develop a popping/crackling sound, noise was resonating through domestic hot water pipes, using a sounding rod it appears the noise is loudest at the safety valve tapping, water level is at specification up 28-7/8" from bottom of jacketing, covering hot water coil. Gauge glass level occilates 1" when steaming. Noise only occurs when calling for heat and making steam, not when responding to aquastat.

I called the install plumber and he said keep skimming, talked to different plumber who does my cleanings he said drain and refill. So this fall I skimmed some more before cooling down and flushing out the boiler twice, water was black/brownish, on last drain and refill water was clearish. It continues to make noise. After a few heating cycles I opened skim port and fired it up black/brown water flowed form skim port. Maybe need more flushing or chem clean?

I called US boiler and made contact with a helpful customer service guy who said you may have to chemical clean it but they don't recommend using chemicals if skimming works. And that if I use chemicals they don't have a reccomendation, he said there are lots of of the shelf additives with who knows what in them.

I'm debating whether to continue flushing and skiming or add some chemicals, so what chemical to add? The old manual from the burham that I replaced suggested TSP .4 lbs and Caustic soda .4lbs for a boiler holding 14 gallons.

My questions for those who had the patience to read this

Am I on the right track with this being carryover caused by contaminated water, if so why did it only begin after several cycles after install?

Should I continue to skim and flush until water is clear?

Should I just chemical clean with TSP and Caustic Soda skim and then flush the crap out of it?

STEAM DOCTOR

8-way for the win. Just make sure not to leave too much in when you are finished. The whole bunch in and fire it up. Once it starts steaming, let it sit for a while. At least 30 to 60 minutes. Fire it up every once in awhile for a few seconds, just to make sure that the water is still hot. Drain and fill a bunch of times. To get out the bad stuff and the excess chemicals. Fire it up and see what happens

EBEBRATT-Ed

Arm and Hammer Washing Soda. I used to use TSP and that is fine as well but Washing soda is ok. Use 1 lb of washing soda for every 50 gallons of boiler water so .306lbs of washing soda is needed for your boiler which holds 15.3 gallons.

1. drain boiler below gauge glass and install a skim tapping with a valve. Pour washing soda mixed in a bucket of warm water into the boiler through the skim tapping.
2. Fill boiler so you can see water level. Start the burner and let it run until the supply pipe is hot but not steaming. shut burner off and start skimming SLOWLY. Add feed water slowly ….you only want a stream of water the size of a pencil. Skim until the water looks clean. An hour should be plenty.
3. Let boiler cool. Drain and refill twice to get rid of washing soda. Refill and run