Dead Men Tales: Air Vents and American History

HeatingHelp

Air Vents and American History

The automatic air vent didn’t come easily to the heating industry. It took hard work and a lot of very inventive thinking. Hearing this story will help you sharpen your troubleshooting skills.

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reggi

Edited to Storyline : Great Story as usual @DanHolohan .. thanks for sharing your experience BTW..they said the 76 was for the Coal Burners?

DanHolohan

I worked for the Hoffman Specialty rep in NY from 1970 until 1980. We sold their one-pipe steam vacuum vents because people were buying still them. They were a major source of system-balance problems on systems firing any fuel other than coal, however. I took those phone calls. When I was researching The Lost Art of Steam Heating, I read a lot of articles in oil-heat trade journals, published '30s. The writers told about the balance problems then, and how it was fuel related. Many of those articles came from the oil-heating industry. It's true that it took time for Hoffman to stop production of their vacuum vents for radiators. People kept buying the because they weren't working as they should, and human nature is just that. The problems were real, and documented. The old-timers at the factory also talked with me about it at the time. They knew.

P.S. Hoffman continues to make the #76 vacuum main vent. I asked the factory why on earth they would keep making that vent. Guess what they said. ;-)

dopey27177

Hi Dan

I remember the first air vents in a steam heating system was cast iron pipe that was used in the one pipe stem heating system. The cast iron pipe had sand holes in the piping and the air vented out of those holes. The problem was the odor from the steam system created problems with the home owner. When the sand holes were found and plugged the system did not work and te pet cocks had to be used to vent the air.

jake

DanHolohan

Good memory, Jake!

t.p.tunstall

Just fantastic dan, fun to read old history in current times, TPT

DanHolohan

Thanks!

gpr

As usual, great story.
Dan, Thanks so much for the education about steam heat. Your info has made my amateur steam tinkering v effective and saved me much cash and headaches. I have bought most of your books and they are excellent.
Thanks for your expertise
Gregory

DanHolohan

Thanks, Gregory. I appreciate you!

jumper

dopey27177 said:

Hi Dan

I remember the first air vents in a steam heating system was cast iron pipe that was used in the one pipe stem heating system. The cast iron pipe had sand holes in the piping and the air vented out of those holes. The problem was the odor from the steam system created problems with the home owner. When the sand holes were found and plugged the system did not work and te pet cocks had to be used to vent the air.

jake

Interesting idea. When room is too cold manually open vent. Why not?

ccstelmo

Back again with my science project in Meeker CO. This article has raised my understanding a exponentially. Many thanks.

All my radiators (9) have original (1938) vents. Hoffman Airport No. 70. Elsewhere I've expressed the thought that steam produced at 6300' is cooler (200 degrees) than sea level steam and have speculated that this probably means vents take more time to close and perhaps have trouble closing all the way. I'm thinking now that even though they close slower, the more "closed" they get (collectively) the higher the pressure in the system is allowed to rise and so, eventually, at 2psi, say, they do close 100% as increased pressure causes increased temperature.

I'm cheap and 9 X $28. is incentive enough to me to repair not replace the vents. I've soaked 'em in vinegar for a week and am about to reinstall them and see if they stop popping, hissing, and singing and carrying on so my wife will stop complaining about them.
OK, so all that is background.

The No. 70 has an adjustable bonnet with 6 holes (drill sizes 48,54,57,60,66, & 70) in it. Under the bonnet, at the top of the vent, is a single hole (drill size 46) to allow air out the top of the vent body. Obviously the holes are there to allow the operator to regulate the rate of air expelled from the radiator. So what's this all about? Why is an operator regulating capability important? Is there some holy grail standard that says all radiators should finish venting at the same time?

BTW: This is in Colorado coal country and the original system was surely fired by coal. It now has a gas-fired Lenox 325K boiler.

(Am I in the right place for this? Should I go to the forum to hash this out?)

mattmia2

How big is the system? Does it match the boiler? That sounds like a huge boiler. What does the water line in the boiler look like when it is steaming? What is the pressuretrol set at? It could esily be wet steam or too high a pressure. What do the main vents look like?

The vents should be different sizes so that the building heats evenly to make up for the different size radiators(bigger radiators and more runout piping to the radiator have more air to vent.) and different loads in different rooms and a few other factors

CharlieShea

Interesting