5 ms·

A couple of comments here mention how great steam heat feels, apart how noisy it is. This is ironic, as one of Holohan's main points is that when operating pr

by nkurz 8y ago

A couple of comments here mention how great steam heat feels, apart how noisy it is. This is ironic, as one of Holohan's main points is that when operating properly, steam heat is silent. The problem is that most people have never experienced a properly operating steam heat system. Here's some quotes from the intro to his Greening Steam (which is a great book, which you should definitely read if you have a steam heat system): Steam Heat Should Be Silent Water hammer, that banging and knocking that is so prevalent in steam heating, is not normal. Don't let anyone tell you that it is. Water hammer is also destructive. It can break pipes from fittings and cause injury. It's not normal. It has definite causes, and you can make it go away. Hissing air vents aren't normal. In a well-balanced steam system, you should never hear air venting. When a vent makes noise, it's trying to tell you that it's handling too much air. Holohan's main conceit is that there are very few plumbers who understand steam heat, and as a result, there are very few systems that work as designed by the "Dead Men". The idea that steam heat is inherently noisy is one of the main myths that he wants to dispel. Tying this back to HN, there's probably some useful parallel here to systems architecture and maintenance programming. How many systems will keep working as well as they were designed after several generations of "repairs" have been performed on them? How can one design systems to make it more likely that they will continue to work as designed?

deleted 8y ago
[deleted]
romed 8y ago
The problem as usual is with the users not the system. If anyone in your building turns the valve on their radiator off (because their space is overheated) then the water will condense and when they open it again the entire system will hammer, forever, until the building engineer drains it. As for the air vents it seems that building supervisors just can’t resist painting them, which renders them inoperable. They should know better. So in summary steam is wonderful as long as humans don’t get involved.
- nkurz 8y ago
  If anyone in your building turns the valve on their radiator off (because their space is overheated) then the water will condense and when they open it again the entire system will hammer, forever, until the building engineer drains it. Theoretically, I don't think this is correct. And in practice, I'm sure it's not always true. That is, I've tuned up a steam system using Holoway's advice, and there was no problem with turning individual radiators on or off. In normal operation, the steam is condensing in the radiator, and then draining back to the boiler by gravity. Opening the valve after a period of nonoperation is not significantly different than the rush of condensation one gets at system start up when the radiator is cold. If the pipes are layed out correctly, when the valve is opened the water will drain back to the boiler with no outside action required. What is true is that the standard "one pipe" steam radiators work poorly when the user decides they want half the heat, and turns the steam valve halfway. In this case, the higher speed of the incoming steam through the smaller opening prevents the water from flowing out, and the radiator works poorly. The correct approach to variable heat on one-pipe steam systems is an adjustable exit air valve. Still, this should also "fix itself" quickly as soon as the shut-off valve is fully opened.
  - Kadin 8y ago
    > The correct approach to variable heat is an adjustable exit air valve. I always wondered why the radiators in some buildings had two apparent temperature controls, one at the bottom of one side (generally a big gate valve) and another at the top of the other side (which I presume is the "exit air valve"). As a student, nobody ever told us how to actually regulate the heat, so there was a lot of randomly opening and closing valves until the thing either got hot or cooled down as needed. Or, more commonly, you just ran the thing full blast all the time and opened a window when it got too hot, titrating the cold air from outside against the overwhelming heat from the radiator. A couple of laminated instructions stapled to the wall near each radiator probably would have made the system perform much better.
- anthonybsd 8y ago
  > then the water will condense and when they open it again the entire system will hammer, forever, until the building engineer drains it That's not true. I've had issues with my house steam system in the past where I added too much water to the furnace and draining the furnace did the trick. Any excess water will simply turn to steam and cycle itself out of the system.
emddudley 8y ago
> How can one design systems to make it more likely that they will continue to work as designed? Perhaps it would need to be antifragile in some way, and have direct immediate feedback on "bad repair" vs "good repair".

by nkurz 8y ago

deleted 8y ago

[deleted]

romed 8y ago

The problem as usual is with the users not the system. If anyone in your building turns the valve on their radiator off (because their space is overheated) then the water will condense and when they open it again the entire system will hammer, forever, until the building engineer drains it. As for the air vents it seems that building supervisors just can’t resist painting them, which renders them inoperable. They should know better. So in summary steam is wonderful as long as humans don’t get involved.

nkurz 8y ago
If anyone in your building turns the valve on their radiator off (because their space is overheated) then the water will condense and when they open it again the entire system will hammer, forever, until the building engineer drains it. Theoretically, I don't think this is correct. And in practice, I'm sure it's not always true. That is, I've tuned up a steam system using Holoway's advice, and there was no problem with turning individual radiators on or off. In normal operation, the steam is condensing in the radiator, and then draining back to the boiler by gravity. Opening the valve after a period of nonoperation is not significantly different than the rush of condensation one gets at system start up when the radiator is cold. If the pipes are layed out correctly, when the valve is opened the water will drain back to the boiler with no outside action required. What is true is that the standard "one pipe" steam radiators work poorly when the user decides they want half the heat, and turns the steam valve halfway. In this case, the higher speed of the incoming steam through the smaller opening prevents the water from flowing out, and the radiator works poorly. The correct approach to variable heat on one-pipe steam systems is an adjustable exit air valve. Still, this should also "fix itself" quickly as soon as the shut-off valve is fully opened.
- Kadin 8y ago
  > The correct approach to variable heat is an adjustable exit air valve. I always wondered why the radiators in some buildings had two apparent temperature controls, one at the bottom of one side (generally a big gate valve) and another at the top of the other side (which I presume is the "exit air valve"). As a student, nobody ever told us how to actually regulate the heat, so there was a lot of randomly opening and closing valves until the thing either got hot or cooled down as needed. Or, more commonly, you just ran the thing full blast all the time and opened a window when it got too hot, titrating the cold air from outside against the overwhelming heat from the radiator. A couple of laminated instructions stapled to the wall near each radiator probably would have made the system perform much better.
anthonybsd 8y ago
> then the water will condense and when they open it again the entire system will hammer, forever, until the building engineer drains it That's not true. I've had issues with my house steam system in the past where I added too much water to the furnace and draining the furnace did the trick. Any excess water will simply turn to steam and cycle itself out of the system.

emddudley 8y ago

> How can one design systems to make it more likely that they will continue to work as designed? Perhaps it would need to be antifragile in some way, and have direct immediate feedback on "bad repair" vs "good repair".