Are these my main vents?

Alix

I have one pipe steam heat and am trying to locate the main vents for my boiler.

I have attached a photo - are the two silver bell-shaped things main vents?

Also, how can I tell if the main vents are working optimally?

Steamhead

Yes, those are main vents- look like old Dole vents.

Measure the length and diameter of your steam mains. This will tell us what to replace them with. At least one of these vents looks like it's been leaking, and I'd bet they are both too small.

Alix

Many thanks Steamhead! I guess the good news is that they weren't replaced with a steel plug. I'm now trying to figure out how to get these measurements. Have you seen a good description of how to do this online or in "We Got Steam Heat" or "The Lost Art of Steam Heating"? I'm wondering where the steam mains officially begin and end. Do I measure the total length of all of the large pipes that run horizontally along my basement ceiling (excluding the branches and risers that lead to the radiators upstairs)? Do I start measuring from the horizontal portion of the "supply main" that is just above the "header" which rises up from the boiler?

I don't have a caliper to get the diameter of the steam mains. Can I get it by measuring the outside circumference using a flexible tape measure and then divide by 3.1415?

Steamhead

For the diameter, we need the inside measurement. Just measure the outside and deduct 1/4" from that to allow for the pipe wall thickness. Then measure from where the mains leave the piping close to the boiler, to the main vent locations. Post the results here.

Alix

I have attached another photo that I think might be helpful. The inside measurement of the black pipe below the "start arrow" is 5 3/4 " (outside diameter is about 6"). However, the inside measurement of the pipes leading up to the nipples that hold the main vents (beginning with the red and black pipes just to the left of the "start arrow sign") are 5".

Measuring down beginning just below the start arrow there is roughly 125" of 5 3/4" pipe (including the elbows, tees and connectors), and then an additional 62" of 5" pipe (leading to the nipples holding the main vents). The nipples holding the two main vents would add an additional 8 1/2".

Measuring ONLY the pipes (excluding the elbows, tees, connectors, and nipples), I got roughly 101" of 5 3/4" pipe, and 45" of 5" pipe.

Side note: the house inspector said the boiler is "very large" at 175,000 BTUH. The boiler is about 12 years old. The house is about 1,800 sq ft (not including an additional 450 sq ft of finished basement). There are a total of nine radiators on three floors above the basement.

Steamhead

Did you measure the circumference or the diameter?

Alix

I wrapped a cloth tape measure around the pipes to get the circumference. The circumference of the larger pipe was 6" and the circumference of the other was 5 1/4".

Steamhead

Actually, you need to start in the piping above the boiler- where one pipe goes up from the header then splits into two. That's where to start your measurements. Also, when measuring circumference, don't deduct the pipe wall thickness unless you first convert the outside circumference to the outside diameter. You can do the conversion here:

http://www.onlineconversion.com/circlesolve.htm

Also, it looks like there is a huge water pocket in the piping near the ceiling. That reducing elbow is turned on its side, so water is caught between it and the tee. This will definitely kill the steam as it comes up, and might cause banging.

The fix is to have the elbow pointing down. This will take some serious work, but should be worth it.

Alix

Hi there, I've attached a new and improved photo.

From 'B' heading right and then down and back up to the main vents at 'D' and 'E' there is roughly a total of 200" of pipe (including the elbows, tees and connectors). The nipples holding the two main vents would add an additional 8 1/2". If we included 'A' to 'B' this would add about 54", and if we included 'B' to 'C' this would add another 46" (including the elbows, tees and connectors).

The inside diameter of the pipe that runs from 'A' to 'B' is 2.66" (outside circumference is 9.13").

The inside diameter of the vertical pipe that runs from 'B' to 'D' is 1.64" (outside circumference is 5.95").

The inside diameter of the vertical pipe 'E' is 1.41" (outside circumference is 5.2").

The inside diameter of the smaller horizontal pipe coming off the reducing elbow next to 'C' is 2.1". The small section of very large pipe to the immediate right of 'C' has a larger diameter than the pipe that runs from 'A' to 'B.' So quite a mix of pipe sizes!

Is the huge water pocket you referred to just to the right of 'C'? (There is a plumbing vent pipe just above it.) About how many hours of work do you think it would take to make the elbow point down? (It's hard to tell from the angle in the photo but it is out of the way of the joist above.) Do you think it has been that way since the house was built 85 years ago or that perhaps it was changed when installing the new boiler 12 years ago?

Steamhead

Right, that's the water pocket to the right of C. I think that was done when this boiler was installed.

So if you start at C and follow the 2-inch pipes all the way around the basement to the vents at D and E, how long are those pipes?

Bio

On another topic, looks like pipes D&E should tie down below the water line, a Pro can confirm this

nicholas bonham-carter

Also a problem is the reduction of diameter in the riser coming off the boiler. This can increase the velocity of steam coming up the pipe, carrying water with it, instead of just dry steam.
If you decide to have all the piping problems rectified, you will notice a substantial reduction in fuel consumption.--NBC

pipergood

I do agree that pipes D and E should tie below the water line. Need to note that I am not a pro just an enthusiast. Also for outside circumference and diameter conversion you can try: http://calcurator.org/circumference-calculator/