Intense boiler noise on start up

Zipper13

This is surely a perennial favorite topic.

Quick background:
This is the 2nd winter at this house.
Boiler is 2008 Burham, gas.
Mains not insulated (It's on the list)
I've posted pictures in some of my earlier questions.
NBP not great but not terrible from what I'm told.

The boiler was silent when we moved in, but the water was green.
Had cleaning/service last winter and the water stayed clear, but the boiler (yes the boiler, not rads or mains) would bang pretty substantially unless I dropped the water an inch below 3/4 full in the gauge glass. It would also rattle like someone shaking a jar of metal BB's for a few minute until I felt the first bit of main get hot. I could live with that.

This past winter we didn't have it professionally serviced. I flushed, skimmed a few times, used Steamaster for while, drained/skimmed a couple more times. Now I'm on untreated water.

Problem
On start up the Boiler rattles like someone shaking a jar of metal BB's. This can be heard throughout the house, most loudly near the radiators, but the rooms are small so really everywhere is near a radiator. Then it bangs for 5-10 minutes. Each bang can be felt if you put your hand on the boiler, but the sound doesn't seem crazy loud standing right next to it. if you go upstairs, the noise is significantly louder and sounds far more concerning. Is it echoing and magnifying through the pipes/rads?

Question
What's causing this? scale/corrosion?
do the bangs cause damage?
are they indicative of existing damage?
What might fix it? I'm not against adding treatments, just not sure what needs to be addressed
Again, it was quiet when we moved in with green treated water then a little less quiet after a cleaning and now is't booming/banging on start up each cycle...then perfectly silent for the rest of the cycle.
thoughts?

Hap_Hazzard

If I had to guess I'd say it's caused by too much carryover, which raises the water level in the mains to the point where it causes differential shock in the mains. Lowering the water level reduces the amount of carryover, and getting the water conditions right could help, especially if the pH is too high.

Does this happen before or after the main vents close?

ethicalpaul

> would bang pretty substantially unless I dropped the water an inch below 3/4 full in the gauge glass

One moment though...what level were you keeping it at where you experienced the banging?

I ask because 1" below 3/4 is still quite high so I wonder what it was before? Too high a water level can definitely lead to water being shoveled into the main especially with marginal near-boiler piping (like mine )

Zipper13

Hap_Hazzard said:

If I had to guess I'd say it's caused by too much carryover, which raises the water level in the mains to the point where it causes differential shock in the mains. Lowering the water level reduces the amount of carryover, and getting the water conditions right could help, especially if the pH is too high.

Does this happen before or after the main vents close?

This is before the main vent closes.
It's a vapor system. My low pressure gauge (new this year) has never shown above 3 oz.

I've never checked the pH. Just regular pool test strips and water from the boiler drain should do it?

Zipper13

ethicalpaul said:

> would bang pretty substantially unless I dropped the water an inch below 3/4 full in the gauge glass

One moment though...what level were you keeping it at where you experienced the banging?

I ask because 1" below 3/4 is still quite high so I wonder what it was before? Too high a water level can definitely lead to water being shoveled into the main especially with marginal near-boiler piping (like mine )

When the boiler guy cleaned and refilled it, he set it to 3/4 full and then I dropped it a little from that.

Before that it was 2/3 to 3/4 full. He marked it on the glass, so I assume he filled it back to where it was before.

I've lowered it to 1/2 and I still get the banging.

ethicalpaul

OK cool. I imagine you still have the header slope issue that it seemed you had (where the header is going uphill?)

That may be where the popcorn sound comes from.

For the other banging, it could be that same cause (like the incorrect slope is causing water to get carried into the main), or there could be other pitch issues elsewhere in your system.

Were you ever able to get a good steam pro out to have a look?

Chris_L

On start up the Boiler rattles like someone shaking a jar of metal BB's. This can be heard throughout the house, most loudly near the radiators...

I also had this noise in my old Burnham boilers--and would also get banging in them, just as the water began to boil. Both used Steamaster. Skimming didn't help.

What did work was Hercules Boiler and Heating System Cleaner. You can get it at the big box stores.

Zipper13

@ethicalpaul , I haven't had any work done on the piping yet. I think that header/equalizer pipe is level (maybe a hair back-pitched depending on where I place the level - the surface is a little rough so it rocks a bit) so definitely not optimum. But I was thinking that the piping couldn't be the culprit since that's the same as it's always been. If I got it to settle down before with these same pipes, why make noises now?
I had a gas guy in to clean a year ago. He has done steam installs and repairs and is listed on here, but I think steam work for him is still rare. The deal I made with my wife is that I'd clean/flush the boiler this year and then next year we'd pay the travel premium for a real pro (highly recommended here) to come out to make some system-wide assessments with the maintenance.

@Chris_L are you suggesting this

https://www.supplyhouse.com/Hercules-35-206-1-qt-Boiler-Heating-System-Cleaner-14603000-p

or this

https://www.supplyhouse.com/Hercules-35100-4-oz-Scout-Steam-Boiler-Cleaner-4-oz

I saw that the Boiler and Heating System Cleaner is siliconized. that struck me as an odd additive for a cleaner; I picture that gumming things up. I'm sure I have the wrong idea about that, but it threw up a flag for me.

Chris_L

@Zipper13, I used the first one, Boiler and Heating System Cleaner. (I'd never heard of the other one.)

I don't know about its chemistry. All I know is that it is recommended for steam boilers and it worked.

Hap_Hazzard

Zipper13 said:

I've never checked the pH. Just regular pool test strips and water from the boiler drain should do it?

If the water is clear enough not to stain the strip it should be okay. If it's too hard to interpret, you might want to pick up a pH meter.

I wouldn't recommend putting anything containing silicone in your boiler.

nicholas bonham-carter

The Ph strips are cheap and accurate. The ones I use are made in Germany, and have 3 color patches, so easier to match up with the chart, in different lighting conditions.—NBC

clammy

Being your mains are not insulated usually this will increase the amount of mud in your wet or dry returns meaning more mud in the bottom of your boiler . When faced w steam boiler that are making noise and producing bad steam . I usually attempt to bottom clean the boiler by removing the return plugs and flushing the block out ,I ve done this and found some steam boiler bottoms completely filled w mud and percolating like a coffee pot or banging after a good bottom flushing and wanding then a refill and skim the boiler is usually silent . As others have stated ph also plays apart in surging and carry over . You should test your water hardiness and tds if it’s deemed high install a califee demineralizer filter it will lower the tds to about 10 to 15 tds level which is acceptable . I would also take a look at your main and radiator vents when main vents are not functioning properly aside from uneven heat bad main vents do not vent all the air out and on dry returns will form a mild carbonic acids which will increase mud and rust and also rot out your dry returns over time . There’s always cause and effect if you figure the cause you can rid yourself of th effects Peace and good luck clammy

Zipper13

I had drained and filled several times and thought I had nice clean water before I posted this question. but then a few days ago I opted to put in about half a bottle of 8-way (I have about 15 gallons of water in the boiler and wet return). Once I added the 8-way, the crackling sound was weaker and shorter-lived each cycle and the banging was reduced a bit too. Periodically I've drained about a gallon out into a white bucket and let it settle out. a couple hours later there is a layer of really fine crud covering the bottom of the bucket. My plan is to let it cook a few more days then do a few drain/refills to hopefully pull out more of that fine stuff. so I'm thinking you;re right about having a lot of junk in there @clammy I don't have any clean outs anywhere, so getting it all out might be a challenge. I'm hopeful that the 8-way will pull a lot of it up into suspension and then I can drain it out over time.

clammy

You could try removing a boiler drain install a ball valve and possible the safety valve and install another boiler drain and then back flush it a few times . It’s unfortunate that no one installed any tee on the boilers returns to enable cleaning . Aside from myself and some of the pro on this forum most installers never give cleaning the water side they would rather replace the boiler every 10 to 15 years lol . I preach it to just about every contractor I assist in steam boiler installs and the issue is they do not want to spend a penny on extras and they do not care usually because they are not coming back plus they know no better and usually they can’t or refuse to read . In some cases I have just removed plugs added nipples and caps or cut elbows and installed tees other then that a lot will just suggest a new boiler and usually they will pipe it the same . Paying some one to do usually isnt cheap and a lot will refuse due to liability of damaging the boilers block . In some cases there’s no choice . Have you tried to locate a pro from this site to take a look ?peace and good luck clammy

acwagner

What's the water level in the site glass doing while it hammers? Or in general when it's running?

I've found on my own Burnham that it's incredibly sensitive to dirty water--both oils and suspended solids. My own boiler took about a dozen skims and flushes over the course of the first year after it was installed to tame it.

I didn't read through all your postings, but if the hammering you describe calms down initially right after a skim and then gets progressively worse over time I would recommend to keep skimming it.

Zipper13

@acwagner skimming doesn't appear to make an difference, but drain/refill makes it run silent for about three or four cycles then back to banging as bad as ever unfortunately. I suspect that the returns are dirty and bring crud back to the boiler after a few firings.

Update:
Most recently, I drained out the half quart 8-way treatment and added another for a few days and then drained that out. Both times I got a LOT of fine rust dust settling out in the 5 gal buckets so the water was (is?) very dirty. It still banged, though not as bad. I'm inclined to repeat these cleanings with 8-way but I don't have any more at the moment.

I did, however, have a bottle of Hercules Scout. I added half a bottle of that two days ago and immediately the noise halted and it remains silent still. I'm not sure I like the idea of this leaving stuff in over the summer since it seems like it would settle out to the bottom over a few months of dormancy and I would fear it maybe crusting up , so I'll likely drain it out again. then keep repeating these cleaning steps going into next heating season.

With any luck, a few more cleanings/drains like this will get the the water to keep cleaner longer. since it never needs make up water, I'll be happy to get it back to more of a set it and forget it situation

dopey27177

Try disconnecting the wet return from the boiler and flush it out with a hose. Most of the crud collects in the wet return because this dirt can't flow up hill into the boiler. The dirt you see entering the boiler is colloidal and floats up the piping with the water into the Hartfort loop.

Do not be afraid to leave the boiler water treatment in the boiler over the summer. To prevent rust from from forming in the boiler over the summer fill the boiler with water to the top of the gauge glass.

Jake