Single pipe steam system. Banging pipes, water coming from air valve.

Asully102

A couple months ago we replaced our steam boiler, and ever since the new one was installed, the pipes are banging when it runs. I have all my radiators pitched towards the supply valve, and that didn't make a difference. I confirmed all my return pipes are slanting back towards the boiler. Changed the nozzle down to a .60, no chance. I have varivalves on all my radiators (5) for the air valves. When I have them all the way open, filthy water spews out. This was never a problem with the old system, only with the new system. The installers are coming back this upcoming week to replace the air valves, but could that actually be a resolution? What else could be a cause and possibly solutions?

Jamie Hall

I doubt it's the air valves or the burner nozzle (I hope you had a full combustion check after you changed that...).

Can you send us pictures showing the near boiler piping?

Not that I'm sure I want to see them...

Asully102

Asully102

Pictures above. And yes, after the nozzle change we ran it for 30 minutes, confirmed the noises still occurred. Ran it again later that night when it cooled down, same results.

neilc

I don't think I see an equalizer,
Sully, do you have your boiler manual ?
or can you post a picture of where the header turns back down to the boiler return

Asully102

I'll look for the manual. Which is the header? Is it the main big pipe coming out of the top?

Asully102

I have the manual. And here are some. More pictures.

nicholas bonham-carter

The Peerless installation manual will give the details of required pipe sizes needed-are they correct on yours, for riser up from boiler, header, and equalizer. Some models may require 2 risers. Give us the outside diameters and we can check from there.
The manual will also give instructions on cleaning the newly installed boiler, (skimming). No additives or chemicals can replace this step, which you may have to do yourself, if the installers don’t know how, or why. I don’t see the required skimming port installed for this.
It looks like your main (not radiator) air vents are inadequate in capacity, and a 0-3 PSI additional gauge, would help to calibrate the notoriously inaccurate standard pressuretrol.—NBC

Asully102

Asully102

I don't know the names of the pipes, this is all new to me. I'll upload a picture of the piping part of the manual shortly the two pictures that have pipes vertically next to each other are in the back. The picture with the measurement on the left pipe connects to the copper in the back, and the right connects to a spigot to the right of the boiler

Asully102

Asully102

And if it makes any difference. The radiators get very hot, and the banging starts roughly 20-25 minutes into a burn cycle

Jamie Hall

I will let some of the pros comment on the piping, but... I'm not happy.

You ran the boiler for 30 minutes after the nozzle change. Wonderful. But did anybody check the draughts, flue temp, O2, CO2, CO, smoke with instruments? If so, what were the values (they should be on a printout left near the boiler).

Asully102

No, no measurements were taken.

Jamie Hall

Asully102 said:

No, no measurements were taken.

Then you didn't do a combustion test. It is required after a nozzle change. Get them to do it.

Asully102

Thank you. I'll let him know when he comes back. Would the results of this test help point in the direction of the cause of banging?

dennis53

I've had bad luck with the varivalve vents. They vent way too fast no matter the setting. I would recommend going with slower radiator vents, faster main vents in the basement, and skimming the boiler. It also looks like your 2 returns tie together above the water line which can cause problems.

Asully102

Thanks. I'll mention that when they come back. They are going to change out the varivalves.

Jamie Hall

Changing the varivalves may help. Some. But you have a serious wet steam problem which your original post states started right after your new steam boiler was installed.

Hmmm...

Does this suggest anything to you? Is the new steam boiler's near boiler piping -- risers, header, equalizer, main takeoffs -- installed as the boiler manufacturer's minimum requirements show? From the photos it does not appear to me to be. Was the boiler thoroughly skimmed after the install? Perhaps not?

I'd start looking at the installation and the commissioning.

leonz

I have never seen a relief valve installed upside down or without a drain line to direct the blow off pressure to the floor.

Why did they not install a drop header to make dry steam?

The remaining cover in the top should expose a second steam tapping to use for a drop header or double drop header? Questions from a novice.

neilc

I was gonna comment on the safety valve,
I don't know who installed that, but I don't think I would let them back in the house,
(I guess the stem is vertical)

as for the equalizer, ok, it's there, missed the diagonal in the early pictures.

what pressures is the boiler running at?
shuts off at what?
turns back on at what ?

dirty or treated water in the sight glass,
does that water level bounce much when firing?
more that a 1/2 inch ?

looking back at the first pictures,
the 2 vents, either as dry returns, or main extensions,
the returns should not connect up there above the water line,
the short drop needs to go to the floor and connect under the water line,
this might be a big part of your hammering.

Asully102

I'm not sure which is the safety valve. Could you let me know? They treated the water. It has a greenish hue in the sight glass. Don't remember the chemical name. I did see the pressure gauge go up to 2 when it was running, and he adjusted that so now it stays at 0. The water does bounce in the sight glass. More than 1/2 inch.

I wish I understood more of the names of what is what here, so I will mention the returns above the water line, I unfortunately do not know what those are.

neilc

Safety Valve,
6 pictures up, where you're measuring 1 inch, behind the boiler, then there's the 90 down(it should be up) and the that brass valve thing with the lever under it, that's your safety valve, and should be with the lever on top, with the stem thru the lever, vertical.
then you still need piping to direct any discharge to within 6 inches of the floor.

Returns and vents,
2 pictures from the top,
vertical pipe right of the boiler,
up at the ceiling there are 2 silver, coned, vents,
the one on the left drops a foot or so, the tees into the line on the right,
that connection needs to be at the floor, under the water line of the boiler.

Asully102

Ah, the picture of the safety valve is confusing. It is not upside down. It is horizontal to the ground, and perpendicular to it is a pipe going straight towards the ground, ending about 6" before hitting the ground. The picture makes it look like that valve is pointing down.

Neild5

Can you get a good picture of the copper pipe that comes out of the bottom of the boiler?  From where it comes out to where it changes to black pipe.

EBEBRATT-Ed

The supply piping header and equalizer look ok to me (if they are sized right) and we are talking a small boiler here .......at least the supply piping can't make out a hartford loop unless I missed it.

I don't like the 2" tee in the header with the plug in the bottom maybe it's not a big deal

The equalizer coming off the header is a little tough to see I think it comes off with a 90 laying on a 45.


If they didn't do a combustion test you can be sure

They didn't skim the boiler

BobC

A newly installed boiler and pipes introduces oils into the system and those oils cause an unsteady water line. that can cause all kinds if mischief in a steam system. Those Varivalves don't have floats in them so they can spurt water. The radiator air vents should be changed to something smaller and more suitable to a steam system.

The boiler should be skimmed to get the oils out, this can take hours which is why some installers are loathe to do it; they usually use a boiler cleaner like Squick; thgee system is likely to bang while the treatment is in the boiler. That treatment is left in the boiler for a week or so and the system is drained down after that to get rid of the chemical and oils. This is not usually as good as skimming but it often stops the anvil chorus from playing every time you use the system.

Bob

Asully102

Here's a picture or that copper pipe meeting black. I have read issues with the varivalves, so hopefully changing those out does help

Asully102

Asully102

Update. I flushed out the boiler and just ran it for 50 minutes and it is quiet. No banging. I'm going to run it a couple times a day for the next week, and see if it stays quiet. Does this just mean there was too much fluid? Or maybe that chemical that was added loosed up some oils and the flushing removed oil?

BobC

If the noise returns it means the boiler needs to be skimmed. Flushing may ease the racket for a while but if it comes back it has to be skimmed, thats not a hard job and a homeowner with a couple of hours time can do it if the installed left you a pipe to skiim from.

Bob

Jamie Hall

And do take it easy on the chemicals -- if you use them at all. Too much is usually much worse than too little.

EBEBRATT-Ed

@Asully102

When they manufacturer the boiler sections they use a lot of oil in the mfg process which the cast iron absorbs.

When the boiler is filled with water and then heated this oil comes out of the metal and floats on top of the water because oil is lighter than water.

This forms a film on top of the water that the steam bubbles can't easily break through. So the boiler doesn't boil right or it boils violently.

The way to fix this is to skim the oil off the top. Draining and refilling seldom works as the oil sticks to the boiler when drained but may get rid of a little oil

It's part of the install process that your installers should have done