need some professional instruction on adding cleaner to my boiler. have some kettling noises when firing and water temp hits around 130+. my initial assessment was to funnel it into the circled air vent port.(see pic). in order to introduce as little air as possible, i plan on the following steps: 1)close the supply 2) close circled valve above circled drain valve 3) open drain valve to allow cleaner to funnel into air vent port. attached are additional pics of overall system. are these steps correct?

also, bottle states 1 qt per 20 gallons. i have no clue how many gallons the system holds. any estimates would be welcome. 88k btu(i think) heat only baseboard system in a 4 bdrm 2100sq ft 2 story house.

 

How are you going to prevent the entire baseboard distribution system from draining out through the vent you're going to remove ?

Meanwhile, what do you think is going to be cleaned out of the system ?

 

by the valve I have circled above the drain. now that i look at the pic the return line is blocked by the gas line.

hard water scale

 

From the pictures you supplied, your boiler looks new of almost new. That being said, what noise is the boiler making that makes you think it is "kettling". Kettling is usually caused by a scaled up boiler , a circulating pump not pumping enough water or the boiler being overfired. (too much gas input)..Some boilers will make a slight gurgle or rumbling noise due to the high heat transfer of the newer thin iron sections. Adding a cleaner is almost always a bad idea unless this was a steam boiler. I would call the installing company or a good service company and ask for their recommendations and to check the operation of the boiler and accessories.

 

It was installed 11/2013. i bought house in 2015. it just started "kettling" several weeks ago. when is firing and hits about 130 degrees it pings, gurgles and a few loud bangs that reverberate through the system.

why is it always bad to add cleaner?

 

Cleaner in a boiler is okay if properly done and not done to the extreme. Too many people will clean their boiler numerous times thinking that that will solve all their problems. Make sure that when you put in the cleaner that you isolate the boiler so no cleaner gets into the system. I would still have the boiler serviced if it hasn't been serviced recently, have the pump checked and make sure that they check and correct the gas input if necessary. From the photo I see that they say no draining. Myself, I never allow any cleaner in a heating system, but that is your call. I never used this cleaner so maybe some of the guys that monitor this site could weigh in with their recommendations.

 

This is a hot-water boiler. The system is sealed and there is virtually no opportunity for scale to form unless the boiler has leakage that goes on for a very long time, causing continuous makeup of water with dissolved solids that build up. Please post a video (with sound) that captures the noise that you are hearing.

My hot-water boiler is nearly 70 years old. Whenever I have had to open up any part of the system for maintenance or modifications, all the internals are as clean as a hound's tooth.