Natural Gas Steam Boiler Rumble

RobLC

Last winter 2014 - 2015. boiler was rumbling enough so that we could hear it through the floor. We went into basement and rumble was accompanied by a burning odor. So, we turned off boiler and restarted after about 10 minutes and it was fine. Two days later rumble returned.

Tech came from National Grid and removed vent limiter (12A09) from Maxitrol RV 53 pressure regulator; he unclogged vent with compressed air and reinstalled it. He said that was the problem.

Now here we are on 2/2/2016 and rumble is back. But this time the rumble is not accompanied by a burning odor.

So, I took out limiter vent last night and the little check ball in the vent was hanging up. I cleaned it up and reinstalled.
We did have 2 large radiators installed on the 3rd floor a couple weeks ago.

Do any of the pros or experienced posters think some of the oil in the brand new rads could have gotten into the boiler to cause the rumble? As I write this post on 2/3/16, the boiler is running well.

Recommend using as additive like Squick or Femox?

Or does anyone recommend taking a closer look at the Maxitrol RV 53 regulator? Maybe get a new limiter vent or replace the whole Maxitrol regulator?

Note: We have two mains and at each end of about 30ft long, we have a Gorton #2 and two Gorton #1's so we get a quick clearing of the air. Heat comes up in the morning in about 20 -25 minutes. It's a 3 story house.

Thank you for any thoughts, advice, guidance, help.

nicholas bonham-carter

What model of boiler, and burner is this?
Do you hear the rumble as soon as the burner fires, or only when the boiler is making steam? A misadjusted burner could make a rumble, and would need to be set up properly with an analyser.
After any piping work, a good skimming should be done, to remove any oil floating on the surface. Adding cleaners will only defer the inevitable need for skimming.--NBC

JUGHNE

Have you checked the water level in the sight glass? If overfilled from delayed condensate return, there is less room for steaming and could produce a rumble as wet steam is thrown up into the header.

RobLC

To nicholas bonham-carter:

Thank you for your help. The boiler is either a 1930/40ish American Standard or Utica (according to plumbers and National Grid.) The burner is an Economite 400 rated at, I believer 400,000 btus max.

The boiler only rumbles, if it's going to rumble when it's making steam, not on start up.

Definitely do the skimming first, as it's just labor on my end, if I remember the flow coming out of the pressure relief valve opening should be no larger than a pencil thickness. And after the skimming we were thinking of putting in the additive.

As far as the fuel mixture, they did a reading with the hand held meter and said it was good and wouldn't want to adjust it.

Thank you, again.

Rob

RobLC

To JUGHNE:

Thank you for your help. You make a good point. Several years ago we did have a problem with the water level going up beyond the top of the sight glass and the pipes on the second floor were banging.

The National Grid tech came and put in a new automatic feeder (the old one was being way too generous with H2O) and that solved the problem.

Now the level is good. When the boiler has been on and pressure reached about 1.5 - 2psi (can't get it any lower with our Honeywell pressuretrol) the water level bounces between 1/4 and 1/2 inch.

We blowdown boiler at lwco and water column once a week. Again, it happened yesterday and might not happen for weeks and then we'll shut it down for 10 minutes and turn it on and it'll be good for many weeks and won't rumble until next season.

Should the little ball check in the limiter vent be free to move around?

Thank you for taking the time to help.

Rob

JUGHNE

This is my best guess and hope others jump in and correct me if needed....I don't have to deal with regulators as such a lot......
A regulator has to breathe just like we do. There is a diaphragm that the gas pushes against. The small vent hole allows the non gas side of the diaphragm to move freely. Just like our diaphragm has to move freely to breathe, (The elephant sitting on our chest would not allow our diaphragm to move very well ). so the little hole under the limiting vent allows that movement. The limiter has a ball that if the diaphragm leaks gas, (it's just a rubber membrane that moves up and down and could leak from fatigue wear) that rapid flow of gas would push the ball up and seal the exhaust hole. Unless you have a problem the ball would probably never move.
With the added pressure of gas on the back side of the diaphragm plus the spring it could cause the outlet gas pressure to rise and overfire the burner. (Just like tightening the spring more by tuning the adjusting nut/screw clockwise)
Then when the burner shuts down the ball may or may not drop allowing the diaphragm to breathe correctly again for a few times. This is a hit & miss scenario perhaps.

So I welcome any opinion's from other Wallies please.

But I think you might need a new regulator, FWIW.

How about pictures of the gas train (reg-valve etc)

Note: This is an occurrence, maybe, that will never happen when HVAC person is on site.

deadmansghost

Greetings RobLC
I have first hand experienced a maxitrol vent limiter over pressure ball check getting stuck. Replaced it, and fired the appliance and about half an hour later the same thing happened again!. Connected manometers to piping up and down stream of the regulator and found that very slowly the utilities service pressure was rising causing a rise in the manifold pressure as well. When the appliance shut down on temperature the couple of inches of excess pressure pushed on the diaphragm and the ball got slammed upwards. Waited for the gas company to replace their regulator outside. Installed another vent limiter and that fixed it. That was 2 years ago, attended to boilers at the same building last summer. Problem never returned. So get your gas tech to return and start looking.

JUGHNE

So the incoming pressure was creeping beyond the working range of the inside regulator? Overwhelmed the inside Maxitrol so to speak?

Often one gets the mindset that whatever the NG company sends in is the gospel set in concrete. On a few occasions I have found otherwise, but always assume it is correct, shouldn't do that. This may be the case here.

Is the National Grid tech from the gas company?

RobLC

JUGHNE & deadmansghost:

Apologies for not getting back to you guys, have been dealing with massive flu fallout - - 3 family members in one house.

The ball in the current limiting vent doesn't move around freely inside the vent, even though Homeserve tech cleaned it out with compressed air. So far the boilers been doing well, especially with that cold arctic weekend we had last week.

We bought a new limiting vent for the Maxitrol RV 53 from supplyhouse.com and the little ball shakes around inside very freely, but not going to fix something that ain't broke. So, we'll just keep it as spare.

Interesting thing about gas company regulator overdoing it. Thinking that the RV 53 should adjust/regulate for correct pressure even though incoming from gas co was too much.

Again, so far so good. Thank you guys, for all your help and input.

We'd like to post some photos of the unit, every plumber or tech from the utility companies are always surprised to see such and old boiler running so well. But now one can tell us who made this thing.

And National Grid used to service our equipment but now Homeserve took over.

Steamhead

RobLC said:

JUGHNE & deadmansghost:We'd like to post some photos of the unit, every plumber or tech from the utility companies are always surprised to see such and old boiler running so well. But now one can tell us who made this thing..

Do it!