Strange knocking noise from boiler

DaveB55

About 5 years ago we had the boiler at our building replaced. This building has 35 units and 4 commercial spaces, the replacement boiler is a Weil-McLain Model #1088 series 1B W/A power flame burner model # cr2-go-20b dual-fired which we run on gas.



There is a strange very loud noise coming from inside sounds like towards the bottom of the boiler about 1-2 minutes after the initial start-up. Also i noticed it is even louder when it is colder outside. After about 1-2 minutes of these loud intermittent clanging or knocking sounds they stop and the boiler runs ok.



I asked a boiler installer about this and he said due to the fact that we have a tankless coil on the boiler (this supplies heat to the one basement apartment) We would need to install a "blanket" on the boiler, cost around $2500. The technician who i spoke with at Weil-McLain also indicates that this may be required. I have no idea what we should do. If anyone has had this experience and can offer us some sound advice, it would be appreciated. I have enclosed some pictures. Thank you.

Charlie from wmass

photos did not post

we do not talk price on here as it varies around the country and globe so we leave that off the wall to make it more peacefull around here.

nicholas bonham-carter

pipe insulation?

i can only think he may have been refering to pipe insulation, which is required for boilers, and will save money and improve performance.

has this noise only just begun, or has it been evident since the instalation? it is often called water-hammer, and is not a normal feature of steam heating.

how often is the boiler serviced, and has the service man made any comment?

don't forget we would like pictures of your boiler for xmas-merry xmas!--nbc

icesailor

Boiler noises:

According to the installation manual for that boiler, if that occurs, you may need to purchase the optional combustion chamber kit.  It is on page 33 or 38. I've already forgotten which page.

You didn't say if it is oil or gas. If oil, and the soot suckers don't clean out the bottom, it may be full of kibbles and bits on the floor of the chamber. You may get hot spots that may cause that noise.



http://www.weil-mclain.com/en/assets/pdf/550-100-068_1009.pdf

Hap_Hazzard

It's on p 33--AND 38

What a memory! How many IOMs do you have filed away in that noggin of yours?



p 33:

On some applications, if draft conditions or burner characteristics cause the burner flame pattern to impinge on the combustion chamber wall, you may notice pinging sounds from the boiler. Adjust the burner if possible to redirect the flame. If this does not work, contact your boiler supplier or Weil-McLain to obtain an optional combustion chamber kit (see page 38 for contents).

icesailor

Bad memory:

A search with Google is a wonderful thing.

All boilers need a refractory rug in the bottom in my opinion. I'd like to see combustion results on a boiler without one, then after just putting one in. When the old ones that used to be minimal and fluffy, fail, I just cut a Lynn Wet Blanket to the appropriate size and install it. Because when I do a D&C on a boiler, I always clan the kibbles and bits off the rug and pull it. You would be amazed at what slides under there.

Without the rugs, I have watched wet oil form on the floor and smoke like a pothead until the returning water gets hot enough to stop it. With the heat reflected back into the flame from the rug, the problem goes away. I'd like to experiment but it takes time. A lot of people are lower in price than I because it takes time to open the front up. It takes even more time when I do it because it hasn't been done before.

Wet blankets are a wonderful thing on those boiler cleanout covers. After the first cleaning, the OEM's are useless except for increasing excess air. Always a good thing for efficiency.

DaveB55

Strange knocking noise ; part 2

Thanks to all of the people who responded and I discovered that after adding another main air vent to the system I have a marked improvement in this noise. I think it was pressure building up from the high combustion burner.

And just to answer some of the questions that were asked : The boiler runs on gas, and yes this has been a problem since the boiler was installed, (about 5 years ago). My pictures will be posted just as soon as I figure out how to post them, should be in a couple of days.

I had complained to the boiler company who installed this unit and they came out a couple of times with the head engineer but they could not figure it out, except to offer to add a 'blanket' at high cost! After living with this situation for so long I got frustrated and that 's why I posted this problem on 'The Wall'. Now although it has not totally stopped it is much lower in decibels than before, so I will continue to look at some of the suggestions which were given and proceed to work on a solution. I hope this condition hasn't caused any damage to the boiler's section or combustion chambers?

If anyone has any more input please advise. Thank you.

nicholas bonham-carter

New main vent

Your system would benefit from having a good low-pressure gauge (0-3 psi, gauge store.com). With that, you will know if your pressure goes above 1.5 psi.

If you want real comfort and economy, you could install a vaporstat, which would keep the pressure below 8 ounces, but your main venting must be generous, showing the escape of air at the start of steaming to take place at 2ounces of back-pressure.

Your burner may have a high-low fire feature, and this could be wired up to the vaporstat to start up on high fire, and then switch to low, as the pressure rises to 4 ounces or so.

As your burner is gas, it will not soot up the boiler so easily as oil, but still needs a combustion analysis every year.--NBC