1-pipe Steam Short Cycling

Cosmo_3

Where are those Weishaupt staging residential burners?

Who was it that metioned them, Josh?

Cosmo

Mike T., Swampeast MO

Please forgive my ignorance, but this topic has come up fairly frequently and I'm trying to understand.

With steam in general, isn't the boiler size chosen for the ability of the radiation and piping to condense steam? With residential one-pipe steam in particular, isn't this quite straight-forward.

Provided that the system is venting and heating evenly, wouldn't this mean that a properly sized boiler would run continually during a heat call regardless of its length? And that if forced to cycle (particularly during setback recovery) that the boiler is quite oversized?

Isn't it also possible to somewhat downfire steam boilers (particularly oil) without problems?

chuckNJ

its the pickup factor

You need the capacity to get all the iron hot but once the system load is good and hot (like toward the end of a long setback recovery), the insulated distribution piping pretty much disappears from the load.

Jamie Hall

and that means

that towards the end of a cycle -- long recovery or (such as tonight around here) just a long cycle -- that pickup load is satisfied, and the radiators won't be able to condense all the steam being produced. And the boiler will turn on and off ('short cycle' -- one meaning of the term, but not a bad one). Unless you have a way to automatically turn down the oil burner during a cycle, you can't keep it from happening (and I'm not aware of any burners which can do that in the smaller commercial and residential sizes). You can't downsize the whole things, as then you'd never satisfy to pickup load...

Jamie Hall

and that means

that towards the end of a cycle -- long recovery or (such as tonight around here) just a long cycle -- that pickup load is satisfied, and the radiators won't be able to condense all the steam being produced. And the boiler will turn on and off ('short cycle' -- one meaning of the term, but not a bad one). Unless you have a way to automatically turn down the oil burner during a cycle, you can't keep it from happening (and I'm not aware of any burners which can do that in the smaller commercial and residential sizes). You can't downsize the whole things, as then you'd never satisfy to pickup load...

Dave_4

nm

Dave_4

Thank you Chuck and Jamie.

That makes perfect sense. There's a load that cannot be neglected from a cold start yet it diminishes and nearly disappears over time.

Then if you insulate/weatherize that pickup factor will only increase as the time between thermostat calls increases since the system has had more time to cool between cycles?

Dave_4

Identity changed again. Previous message (shows from Gene Davis) from me.

This does lead me to another question.

Wouldn't the temp of the piping give great feedback for staging/modulation with quite limited turnback (say down to 75% of gross input) required?

jp_2

hey,

i just got stuck the gene's ID too???