Sizing riser for drop Heather

AMservices

I'm on my way to pipe in a ECT -06, Peerless oil fired steam boiler.
The boiler is serving a home with 900 square feet of radiation, it is a two pipe air vented system, that has managed to retain a good 90% of its original asbestos insulation.
We're planning on using a 2.5 nozzle on the Riello burner and I calculated the steam velocity leaving the 2 - 2 inch tappings to be 33 feet per second.
The boiler is comically smaller in size compared to the one we removed.
I want to pipe 4 inch drop header to the 1-4 inch Steam Main and my question is, do I increase from 2 inches to 4 inches off the boiler block immediately or do I keep the 2-inch going up to the 90's I'm turning down into the drop header?
I'm pretty sure it's unavoidable to keep all of the water in the boiler on Startup. So is it better to try to have the water fall back down into the supply toppings or have it throw the water around back in through the equalizer?

Another problem I'm facing is the new boiler waterline is a foot lower then the old water line.
Do I put the boiler on a pedestal or do I pipe a false water line?
There is a wet return piped around three-quarters of the basement. Really trying to make sure those wet returns stay wet.

Thanks

EBEBRATT-Ed

It looks like you looked this over pretty well. I would raise the boiler 1 foot to match the water line.

If you make the risers larger the water will stay in the boiler which would probably be a good Idea especially since you said that the new boiler is much smaller than the old boiler. Water content is always a concern.

I realize raising the boiler and changing the riser size is a bit more work. Since your using a 4" header where peerless calls for a 3" header and 2 2" risers if I had to pick only one change I would just raise the boiler.

EzzyT

You could raise the boiler just like @EBEBRATT-Ed suggested just make sure you have your dimension B otherwise go with a false water line.
I would pipe a 4" header with both boiler riser 2" going right into the 4" header

STEAM DOCTOR

Don't know what's going on there but might be easier to repipe the wet return.

Jamie Hall

Raising a boiler isn't all that hard. Get the installer to build a nice sturdy concrete pedestal and off you go. No big deal. To get around @EzzyT 's concern -- which is valid -- just make sure your pressures are correct and low.

AMservices

Thank you. I have the boiler up high enough to have the wet Returns full of water.
I'm going to put 2 inch unions on top of the boiler block and increase to 4" from there.
If I run into a problem I can just separate the unions and make the risers out of the boiler 2"

Jason_13

the only concern is if there are return connections that used to be wet and now could become dry. Th8s would allow steam into those returns and affect heating.

New England SteamWorks

According to Dan, increasing the diameter right out of the boiler block doesn't do any good because the tapping size is what will dictate the exit velocity. So I always wait until the 90s to increase pipe diameter. When I am faced with 2" tappings on a boiler that size I like to make them nice and tall. 30" minimum.

If your wet returns remain wet with the new waterline I'd skip trying to raise the boiler a foot. Better to have the height in the piping to keep the steam dry, imho. Good luck.

EBEBRATT-Ed

I guess the question is should we upsize the risers which I guess would have the effect of a water shower back down on the steam coming up from the boiler tapping

or

Keep the risers the same size as the boiler tappings and let the header do the separating.

Cant think of any boiler mfg. that specs risers bigger than the tappings but I could be wrong.

That being said is there a limit on the riser length???

Jamie Hall

I can't think of why there would be a limit on riser length, at least any sort of reasonable length! On the water line issue, though... if you do decide to not raise the boiler, spend some time and trace every darn pipe in the system to be absolutely 100% sure that what is meant to be wet is and will stay that way. It can be surprising to find a water seal out in the far corner of the basement which is now dry...

AMservices

I raised the boiler to the old water line. Only needed to raise 9", so 8 block and some marble tile the home owner had left from a bathroom remodel, got us there. It really added a nice touch to the installation.
I know I last said that I was going to try increasing the risers at the tapping from 2" to 4", then learned about the potential of the boilers water being suspended in the risers, essential raining down on the steam trying to get out. So the 3 of us decided it better to let the steam throw the water with it as it leaves the block and dump it right back in through the equalizer, rather then have it fight it's way out.
We can up 24" off the top of boiler, over and down in 2", then increase to 4". Didn't see any advantage of increasing the risers until turning down if the idea is to have the header do the seperating.
Worked Great! Very happy with the results. The boiler heated quickly and quietly, Next to no surging. I was really doubting those 2" tappings because last week I piped a Smith boiler, a 1/3 of the size, that had 2-3" tappings and the ECT-06 was 1/2 the physical size of the 40 year old Smith boiler it replaced.
The water line was only a few inches from the top of the block. I was expecting half the water in the gage glass to drop on Startup. Barely dipped 1".
I want to put pictures up and I will when all the finishing touches are done.

Jamie Hall

Sounds great! Love to see pictures!