Best Of

It does. There are several versions of the manual out there, but they all say that if the boiler is 5 sections (150,000 BTUH input) or more, it needs two risers to the header. And they say to make the risers the full size of the outlet tappings. The two largest sizes (262,000 and 299,000 input) need 3" headers.

Here is my one and only idea:

RTFM!!

Can't read the manual or is so smart he thinks he doesn't need to read it. Trouble is his work says that he does need to read it.

Its all wrong.

Old rule of thumb from way back was to take the price of the boiler and double it.

That is not enough. Taking the price of the boiler and all the material needed to install it and doubling that may get you close.

Or the boiler cost x 3

Either way it doesn't matter. Labor prices vary from area to area.

Some installers do a great job and some do the old cut and slide.

You get what you pay for.

Much more than twice the retail price. Domestic iron piping is quite pricey and slow going.

And Labor rates depend mostly on the cost of overhead where you are. There you get what you pay for.

And if you can afford it, you should look outside the boiler room and correct any problems that hacks and time have invested into the system: Old mismatched painted radiator vents, leaking valves and ancient rusty wet returns. It may be the first time anyone's putting work into the system in eighty years.

Vents won't affect water hammer, nor help you here. I don't particularly like those main vents you chose but they might work OK.

But for now forget the vents.

What happens to the water level in the gauge glass when you are making steam?

I suspect you are surging due to the insane boiler piping and probable bad water quality.