Old Steam Heat Banging & Priming Rusted Water

kevinlearynet

We moved into our first house about 5 months ago, and have been using the steam heat for about 2 months now. The house was built in 1920, and the radiators appear to be old, but the boiler is a newer Burnham independence.



We've been having trouble when the system is set at 68 and the boiler is working consistently. The pipes begin to bang at consistent intervals and water in the site glass get's very rusted, priming up and down about 1 inch. It's a little hard to see, but here's a video of the priming:



<a href="http://www.youtube.com/watch?v=5AwbThm0Jtw&feature=plcp">http://www.youtube.com/watch?v=5AwbThm0Jtw&feature=plcp</a>



When the banging starts I can tell that the priming is happening, as time goes on the pipes begin to bang at faster intervals and eventually I end up flushing out some of the water which is black and rusty.



So far I've tried the following:



<ol><li>Opened all radiators valves entirely throughout the house

</li><li>Leveled all radiators using shims with a pitch towards the intake pipe

</li><li>Flushed the system (~4 full buckets) every 2-3 days now for 2 weeks straight and the amount of rust seems to be consistent (black and bad)

</li><li>Cleaned vents with vinegar on loud radiators

</li><li>Measured the pitch of pipes leading back to the boiler, all seem to be sloping correctly except for a portion of the pipe just above the vent, highlighted in red in the photo below</li></ol>



The banging seams to be coming from a specific radiator, or possibly the piping below it in the basement.



Any ideas would be greatly appreciated!



Thanks

BobC

Skimming?

Does the banging stop for a while after flushing the system? That boiler may never have been skimmed, newly installed boilers introduce oils into the system that have to be cleaned out. Flushing seems to help but it usually takes a few skimmings to really get the boiler and piping clean. I don't see a skim port on that boiler but it may be on the backside (see picture below , tapping "L" - 1" ), you should consider adding one if you don't have it.



One of your pictures showed a couple of main vents, what kind are they and do they both seem to be working? About how long is each steam main? Try to localize where the noise is coming from, that pipe that is sloped wrong could be part of the problem if it's allowing water to pool in the pipe. After we get the noise taken care of the piping in the cellar should all be insulated. What kind of radiator vents do you have and are they all working?



How far down is the hartford loop connection (see the circled portion of your picture) from the boiler waterline? If the priming is getting down to the level of that hartford connection that can lead to water hammer. Your boiler header piping is not really correct but lets address everything else before getting into that.



Bob

kevinlearynet

Follow-up

Thanks for the thorough response Bob,



The banging seems to settle down for about a day or two after a flush. A picture of the backside is attached, there is a spicket in the top right. This, along with one other spicket near the floor on the opposite side, is where I have been draining/flushing the system with buckets.



I'm not certain what kind of of main vents they are, how can you tell if they are working? The one closest to the boiler (right hand from photo) emits steam, the other one doesn't seem to at all.



I've localized the noise to a first floor radiator (in a photo above), that seems to be where it is by far the loudest, but there are other points in the house that occasionally bang similarly as well. Are the steam mains the 2 vertical pipes next the hartford connection? If so they are close to 7ft in height.



I may be incorrect about the pipe being improperly sloped, a magnetic level attached to that portion of the pipe is attached below. Another photo has been attached of the hartford switch location relative to the water level in the site glass, I would say that the water level is about 2 inches above it. I've just turned the thermostat to 75 and the priming does go below that by about 2 inches.



Thanks so much for the assistance, and apologies if any of the information is impartial or incorrect, as a first time home buyer I'm picking this up as I go.

BobC

Dirty water and venting

Kevin,



The fact the noise goes away for a while after flushing tells me your boiler water is dirty. Flushing doesn't get rid of the crud because as the water level goes down the crud just coats the inside of the boiler and when you start making steam the crud gets back into the water. The place for the skim tapping on that boiler is the upper left corner diagonally across from that drain valve. There should be a knockout on the jacket that would expose the blocked skim tapping. Getting that tapping out after a few years can be a real joy. This thread discusses the use of steam master to help clean and maintain the boiler water, read the entire thread.  http://www.heatinghelp.com/forum-thread/143361/Steamaster-tablets-water-treatment  When you have someone in to service or tune the system ask them to add a skim port and cap for you (or you can do it yourself next spring)



Read over this post and print out the Venting pdf that Rod put together that I attached below.  That will help explain why venting is so important. The mains are the long heavy pipes that snake around the basement and have radiator feeds coming off them. Those 7 ft vertical pipes are the dry retuns that feed the wet return, it's important that the vents on top of them work and are large enough so the air leaves the system quickly and you don't waste gas.



Your Hartford loop looks a little high but will probably be ok as long as you keep your boiler filled to the mark on the jacket (fill it when the boiler is cool).



Bob

Bio

Bull "T"

Your header piping is wrong, you have what's call a bull "T" and is carrying steam and water to the mains, needs to be re-pipe

kevinlearynet

Steam Venting

Thanks so much for the detailed advice Bob,



I'll check in with a service guy about installing a skim port, and will look into using steam master tablets to clean out the system.



I do have one other question for you if you have a moment. We have 2 radiators that vent steam quite loud, I'm planning to run to home depot and get some new vents and possibly some graphic packing to repair gaskets.



Are there any recommendations you have for vents on a system like this? I'm currently thinking of getting the Hoffman adjustable angle shown in the PDF you attached.



Thanks again for all of your help

Mark N

Vents

Do not buy your vents from Home Depot. Go to your local plumbing supply house or order them from pexsupply . Check out Gorton's or Hoffman's.

BobC

Vents

Some of your vents are Ventrite #1's and those are very good vents, if you have one that isn't working you could try boiling it in vinegar for 15-20 minutes to get rid of any calcium deposits in it. That might screw up the knob on the bottom but you'll still be able to adjust the brass shaft.



The Hoffman 1A adjustables are good vents but they are not as quiet as Gortons (might be better for a bedroom); unfortunately the Gortons are fixed so you have to know what size to buy. Maid O mist (or Jacobus) makes a vent that is a lot like the Gortons except it comes with five different orifaces so you just select the one you want. You won't find most of these at home depot, you have to use a supply house or order them from pexsupply.com. The Maid O Mist with the 5 orifices is available from Amazon.



The Gorton #1 is probably a good place to start for main vents, you can use more than one if you have to by making an antler to mount them on.



Bob