150,000btu 383sqft Dunkirk/ 621sqft installed radiation, Need I say more?

Double D

This system is a Bishop & Babcock vacu-system. It appears the crossover traps are failed closed. It also appears the water fell out of the wet return at its highest point where the ends of mains join but I'll need to go back to double check for that. The pics show more of the story. So far all I've done is remove the vacuum breaker from the dry return and installed one Gorton 2.

Steamhead

Time for some sawzall surgery.

The Steam Whisperer

Orifice plates in the supply valves would probably get that to work and heater better that a "full sized"

EBEBRATT-Ed

I'll take the copper for scrap!!

Looks like 2" feeding 6". What's wrong with that?? Poor boiler didn't have a chance.

The installer probably uses the same size boiler on every job regardless of load

"That's the one I always use"

JUGHNE

As the Steam Whisperer" mentioned that orifice plates in the inlet valve, NBP and insulation would make this an interesting study in under sized (for EDR) boilers that may heat the building.

Double D

I have considered all of the above but if the boiler is still holding water and the owner is happy with the way it heats the house, I leave it up to them to decide when it gets replaced. Before I came up with the total EDR, I mentioned orifice plates in the supply valves.

The Steam Whisperer

As long as the boiler has enough capacity to meet the heat loss plus any piping losses, there shouldn't be any trouble heating the building once orifices are installed. I now have quite a few buildings which we fire well under the radiation load and have no trouble. I have a 10,000 to 12,000 sq ft home nearby which only fires at about 1/3 to 1/2 capacity nearly all winter ( the second boiler is manually shut down) with no trouble. Depending on the system and orifice sizing, we can at least go down to 25% of radiation capacity and still get even heating in larger systems.

Double D

I have an email reply from Scott at Tunstall. He sent an article as an attachment. It turns out I already have that article in my documents. Along with the recommended drill sizes to use for the orifices it goes on to say to operate the system at 2lbs. This is a 2 pipe vapor system. I was going to install a vaporstat to lower the pressure. Should I stay with the existing pressuretrol and operate the system at 2lbs after all of the orifices are installed?

ratio

IIRC a vaporstat will operates at 2#? In any case, the steam pressure directly dictates how much steam flows through the orifice. The table you have is likely sized for 2# ΔP, if you lower the pressure the orifice will flow less steam. How much less, I don't know.

It occurres to me that an orifice steam system could be modulated by altering the ΔP, either by controlling the steam pressure or by the back pressure (vacuum pump).

EBEBRATT-Ed

If you can get the pressuretrol to control accurately at 1-2 psi then it's fine. A vapor stat would probably do a better job.

Double D

The recommended vaporstat would be a L408J1017 0-4? I doubt I could get a pressuretrol down that low accurately.

JUGHNE

The first time I saw orifices in a steam valve union I was doing a complete trap changeout and valve repair/replace.
The traps were about 60 years old and had never seen daylight(literally, as they had been covered by book cases).
After 60 years some orifices were worn larger or torn as they thinned. Some had been lost as the valves were accessible.
I replaced all trap elements and some valves and installed new orifices. I unwittingly went with the 2 PSI sizing and am still kicking myself. First the PSI will run up to 2.5, even with a new pressure control. Vastly oversized boiler and thermal envelope has improved drastically, so all rooms will easily overheat, throttling the valves is sketchy.
I should have sized the orifices for only maybe 60% of the EDR to prevent overheating....1,080,000 input connected to 418,272 BTUH load (by EDR connected). But it already short cycles during operation.......this is just opposite of your situation.

So when a vapor system came along that had all trap guts removed, I went with orifices sized for 12 oz as first guess to run only 80% EDR. With vapor stat we can heat well on a long cycle that will seldom shut off on pressure cut out of 10 ozs.

You can always drill larger as needed.

I order all the orifices drilled at 1/8" for pilot hole, stealing an idea from Henry Gifford, put the orifice in a new union with 6" nipple attached. Hold this as your vice for drilling to wanted size.

I used the hopefully attached chart.....furnished by FIZZ here on the wall.

Double D

@JUGHNE, Thank you very much for the chart showing drill size for ounces. I would prefer to drill for ounces and have the ability to increase if need be. I did see the trick about using a union, a 6" nipple and cap for drilling in the article Tunstall sent me.