valve help

Bill_59

Recently I bought an appartment with a steam heating system. Vintage 1920s, I believe it to be a vapor type system. Old coal fired boiler was converted to oil then to gas and then replaced with a newer Peerless boiler(this based on looks of old boiler and oil tank slab on property). The Peerless boiler serial number starts with 61 so does this mean it is 1961 vinage? There are 24 radiators with Hoffman 17C traps and Crane 100 valves. Anyone out there familiar with these lever handled valves? Looking into the outlet side I can see several holes in a dome. Is this an orifice type throttling valve? Are the steam traps necessary? or added later with the newer boiler? Run of longest main and riser is 100 feet. Old main is 4 inch fed by a 2 1/2 inch from new boiler does this mean that presser drop is about 4oz? and system should be on a vaporstat running on 8oz?

Tenants say that the pipes bang in the winter. I read The lost Art and looking at what I have has raised lots of questions. (A little knowledge is a dangerous thing.) I'm in Omaha, Nebraska, know of any good steam men here? I tried the find a pro but all it listed was a hydronic guy.

patrick linhardt

questions

Hi Bill,

1)I don't know about the serial number, I sell Weil-McLain.

2)The Crane valves sound like a metering valve that can be adjusted to balance the steam distribution.

3) The traps were either replaced en mass, since the 17c is a current style trap not available when the building went up, or added to the radiation at some time. That is hard to determine from the info so far. I would suggest keeping them in place for now.

4) The boiler size determines the pipe sizing. Vapor systems used a larger size pipe to decrease pressure drop since they would operate at low pressures. Many two pipe systems work much better at the lowest possible pressure, so a vaporstat operating the system at 8 oz. would be great. Check the main vent size if operating at low pressure, and for best economy.

5) The water hammer could be a number of things, but if the pressure is up too high right now, it could be the cause. Adding the vaporstat might make that go away.

Let us know some more info, boiler size especially. We can make this work right. I'll try to find some info on the Crane valves.

Best regards, Pat

Bill_59

valve help

Thanks for your reply to my ?s. I found the packing list for the boiler and it was shipped late Feb 1981 so I'm figuring that it was installed in March of 81. It has a 2 1/2 inch riser and pipe feeding the old 4 inch main of the origional boiler. Should this pipe be insulated?

patrick linhardt

always insulate

Hi Bill,

Yes, any and all supply piping on a steam system should be insulated with at least 1" thick fiberglass. It improves system efficiency and performance.

What is the size of the boiler? Most of the time the supply pipe size from the boiler header is the same as the main pipe size. I think that it would be a good idea to compare the boiler size to the 2-1/2" supply to make sure it is large enough. If it is too small, steam velocity can carry water out of the boiler to potentially cause water hammer, poor performance, and an erratic waterline.

I couldn't find any specific info on the Crane valves. Do they look original, or could they be replacements?

best regards, Pat

Steamhead (in transit)

The only thing I would add here

is that if traps are leaking, they can cause the dry (overhead) return to bang. If the dry return is steam-hot, follow the heat back to the leaky trap and fix it. If these are the older 17C traps, updating all of them with new Hoffman or Barnes & Jones or Tunstall inserts is a great idea.

If you need more than a pound or so at the boiler to distribute steam, you have an air venting problem. Check the ends of the steam mains for vents- these may actually be crossover pipes with radiator traps in them, directing the air to the dry return. If there are no vents you must add them, if there are they may be bad or too small. The dry return must be well vented too. If the air can't get out, the steam can't get in.

Crane made all kinds of valves back in the day, so I'm not surprised to see their name on orificing Vapor valves. Many Vapor systems used this setup- orificing valves combined with traps. The Hoffman systems were one common example.