Near Boiler Piping Questions

RDG151

Hi, everyone. This is my first time posting, but I've read through a bunch of other posts. I just bought a new house with a steam boiler. With the help of the Gill/Pajek venting pdf on this site, I got the venting straightened out (it was all over the place). Now I’m looking at the near boiler piping.

Currently, the house heats evenly, and is very comfortable. The system has 400SF of connected radiation, and it’s served by a Peerless 63-04 gas-fired boiler. There is one 2-1/2” main which runs in a loop around the basement; it’s 105’ long with 1" insulation.

Out of the boiler, a single 2” riser goes through a 90-degree elbow and feeds directly (horizontally) into the main. I’m wondering if I should simply revise the piping to match the IOM, or if there are efficiencies to be gained by going to (2) 3” risers and a 3” header. Since the main is at 2-1/2” and using 3" would lead to an increase in velocity between the header and main, is there any benefit to this compared to (2) 2” risers and a 2-1/2” header? Does a drop header make sense here since we have pretty good height to work with, or is it all about the pipe sizes?

Another thought that crossed my mind – are we currently getting wet steam even with the height of the existing 2" riser? Or will the steam in the system be dry but overall efficiency is poor due to steam condensing in the 2” riser?

Any insight would be greatly appreciated. Thanks.

SeanBeans

Could you take a few more photos from further back? Also a few different angles of the piping above and beside the boiler.

EdTheHeaterMan

With even heating and no annoying noise... why bother with it? If it ain't broke... Don't fix it!
But if you do.... wait until you have a year of fuel usage... then make your upgrades... (not fixes) and compare the fuel usage before and after! (Take into consideration degree day info to be more accurate). This would be interesting to know. But other Steamers may know more!

Hap_Hazzard

The biggest problem I see is that the "header" doesn't go straight into the equalizer, so it won't remove entrained droplets, if any exist. The height of the riser should prevent carryover, but at high steam velocity, there might still be entrained droplets, and these droplets would be more likely to continue out the main than into the equalizer, because that's the way the "wind" would be blowing them. The header should go straight into the equalizer, and the supply riser should come off vertically at a right angle. This causes the droplets to go into the equalizer because of their inertial mass while the steam is able to turn the corner and go on up to your radiators. As it is, the droplets would tend to splatter against the bull of the tee, then get blown along with the steam into the mains.

acwagner

The boiler manual pipe sizes are considered the minimum sizes. Going larger gives extra "insurance" for dry steam.

You can calculate out the velocity and see the difference between the piping options you listed. The Lost Art of Steam Heating has a procedure in chapter 4. It also gives recommendations for maximum velocities to stay within for the risers.

Once you're within those recommendations, going any bigger really doesn't gain you anything, in my opinion. You'll just be spending money with little gain.

lchmb

the heats good and no noise? and you want to fix what? I think i'd find other more important issues and work on this one later if i was bored...

RDG151

Thanks for the replies, everyone. I'll be buying The Lost Art asap.

My thought was to re-do the piping if there were utility savings or it would correct some other issue. The current configuration doesn't have swing joints (right?), and the riser is less than the minimum recommended by peerless. And there's really no header. Just intuitively, this must be wasting fuel... right?

So now I'm wondering what the function of a header is, and is one required in a single main system?

RDG151

I do really like Ed's suggestion to track the bills for a year. Without actually doing that, I'm thinking any fuel usage model will be challenging to approximate.

clammy

If I or any other pros listed here had installed it it would have had both 3 risers into a min 3 header w a single 2 1/2 take off 2 inch equalizer and a 1 1/2 Hartford loop simple as that .this would give your the driest steam possible which in turn would give you better performance in general and having a boiler piped properly helps in some cases w distribution issues due to wet steam produced by bad near boiler piping which is very common . It’s really up to you but doing it correctly is never cheap or easy .peace and good luck clammy

Hap_Hazzard

RDG151 said:

Thanks for the replies, everyone. I'll be buying The Lost Art asap.
My thought was to re-do the piping if there were utility savings or it would correct some other issue. The current configuration doesn't have swing joints (right?), and the riser is less than the minimum recommended by peerless. And there's really no header. Just intuitively, this must be wasting fuel... right?

You only need swing joints when you have both risers connected to the header. The purpose of swing joints is to allow the boiler sections and header to expand and contract independently of each other. This is important because the boiler heats up and expands before the steam rises into the header and causes it to expand, and the boiler also stays hot longer after the cycle ends. Also, cast iron and steel have different thermal expansion coefficients. Without swing joints, the heating and cooling cycles would put excessive stress on the piping and, more importantly, on the connections between the boiler sections.

RDG151 said:

So now I'm wondering what the function of a header is, and is one required in a single main system?

The purpose of the header is to deliver dry steam by separating the steam from any water that has gotten caught up in the flow of the steam (called entrainment) or condensed from the steam in the risers and header at the beginning of the cycle. It does this by exploiting the differences in the physical properties of water and steam.
Water is heavier than air, and steam is lighter than air, so it should be pretty easy to separate them by density. The trouble is, the steam moves really fast—faster than you can really appreciate until you see a demo of a boiler with glass piping—so small water droplets can get blown along in the racing current of steam. So the first thing a header does is to slow down the steam by providing a larger cross-sectional area, allowing a large volume of steam to flow at a relatively low velocity. This allows the droplets to fall to the bottom of the header, which is slanted towards the distal end, which is connected to a vertical pipe called the equalizer that allows the water to drain into the boiler.
Additionally, entrained droplets that don't fall out of the stream tend to move in a straight line towards the equalizer, because of inertia, while the lighter steam exits the header into the system risers connected to the top of the header.
A header is required regardless of how many system risers and mains are connected to it. In fact, it's more important with a single main, because the steam velocity in that main has to be pretty high if it's supplying steam to every radiator in your house, so you'd better make sure the steam is really dry before it reaches the main.

RDG151

Ahh, I see. Thanks for the explanation.

So I'm thinking my plan will be to track heating bills
and outside air temp for a season and then switch out the 2" riser and header to 3". That will bring the velocity down from 30ft/s to 13ft/s.