Inadequate Venting

MarkReynolds

Hi Folks;

Can I get some advice on the venting on my one pipe steam system?

I live in Michigan (it is 15F outside now). I am trying to get my one pipe system to be as efficient as possible. It works OK. I bought Dan's trio of books, and I am suspecting I may not have enough main venting.

The house is a three story Victorian built in 1900. 4800 sq. ft., is has been insulated and has storm windows and a decent blower door test result. there are 21 rooms including bathrooms and pantries, and 22 radiators currently. The boiler is a 4 year old Burnham, model SIN8LNC-LE2, rated at 245,000 BTU/ Hr. The Pressuretrol is set at the lowest possible setting, Diff =2. , and Main =2.

There are 2 Hoffman 4A main vents, one each on two of the three mains. Mains are 3" pipe, and are pretty long, I have attached a rough layout; dimensions are rounded.

All radiator vents were replaced in the last few years, with Maid O Mist with various size orifices.. All the mains are insulated; I need to get a bit more on the boiler piping.

Photos of the boiler to show piping, plus the two vents are also attached.

I used 473 CCF of gas in December, about normal for this month. Anything I can do to get this system to work better is of use.

Based on the books, and some surfing on the Wall, i think I need more main vents. Any advice on what to do?

Thanks,

Mark

Steamhead

What cute little vents!

They're completely useless on such large mains though. Someone probably got the cheapest ones they could find.



Start by venting each main with two Gorton #2 vents. You can tee both of them onto a single vent riser. Watch the difference!

BobC

Too low

My guess is that your main steam line venting is much too low. Is that  2" an outside or inside diameter?



Also the presuuretrol should be set to 0.5PSI on the front tab and 1 on the wheel inside the front of the pressuretrol. That would let the boiler run between 0.5 and 1.5 PSI until the thermostat is satisfied. Your pressuretrol is the new type but see if you can get it lower, take a close up ,picture so we can see the settings.



Steamhead gave you good advise - follow it.



One other thing, all the pipes in the basement should have a minimum of 1" of pipe insulation on them.



Bob

MarkReynolds1

More Information

Thanks for corroborating what I suspected. This is not the first

screw-up out of the contractor that did the valves, so I am not

surprised (well regarded, locally, too!).

Attached is a picture of

the pressuretrol, it is at the lowest marked settings possible.

Two

more pieces of information.

One, I turn off the radiators (shut

valves, 5 of them) on the third floor (only need heat in the Billiard

room when someone is playing).

Second, the mains are three inches in

diameter, not two (outside measure). Also,a few elbows are market as

3".

I will get more vents this week.

Question. The main leg

furthest to the left in the diagram does not have a vent at it's "bottom

end" (referred to the position on the diagram). It is vented, it also

crosses over an connects to the leg on the far right in the diagram; a

vent is close to this junction. Do I need to vent the bottom end too?

There is a 1/2" plug in the elbow to the drip leg at this bottom end.

However, clearance is tight to the ceiling, only 4".

Thanks very much

for the help.

Mark

Rod

Main Vents

Hi Mark- Just to give you an idea of the venting difference.

 A Hoffman 4a  at 1 ounce of pressure vents .133 Cu ft per min

A Gorton #1  vents .330 CFM

A Gorton # 2 vents 1.10 CFM



I would follow Steamhead's suggestion and vent your mains well. You can get Gorton vents at Pex Supply on the internet. While you can vent radiators too quickly, you can't over vent mains

. As to the venting on that branch. How many radiators are up stream from the boiler beyond the point where it now vents? 

Your local guy may be okay but just doesn't understand steam. I had the same sort of problems with my local guy in rural Maine. He's great with burners but really doesn't have a clue about steam. It really is a Lost Art!

- Rod

MarkReynolds1

More Information

Only one radiator is served by the last leg of the left most main, so I guess I do not need to put a third set of main vents on that leg - correct?

Thanks for the help.

Mark     

Polycarp

asbestos

On an unrelated note, that pipe insulation looks sure to be asbestos.  It also looks like the cloth binder is starting to give way in some places.  You need to either get it removed or sealed.  You could always just encase it all in more insulation.

MarkReynolds1

Asbestos Encapsulation

I do have a few areas of main pipe with asbestos that should be covered (but most of it already is, with the fiberglass tubular stuff).

The areas in the picture have a lot of other mechanicals that make it difficult to add more insulation. So, I am looking for a supplier of the encapsulation material - the one that is sort of like plaster cast material.

Does anyone know who sells this?

Thanks.

Mark

Charlie from wmass

it is plaster cast

material actually.