Some (maybe) new ideas about Master Venting...Boilerpro

Boilerpro

> Hi Dave, it must be getting cool at night because <BR>
> I've started to think about the "system" again. <BR>
> Steamhead suggested master venting my third floor <BR>
> risers and maybe using TRV's (or just 1A's) for <BR>
> control. Those are huge rads, 100 sq. ft. It <BR>
> would have to be about -80 or colder for the rads <BR>
> to get cold all the way across. I plan on using <BR>
> Gorton D's on the vertical mains, just before <BR>
> they go through the 2nd floor ceiling. That will <BR>
> vent them without having to the do the more <BR>
> elegant thing, moving the rads and replacing the <BR>
> valves. Then we can use the TRV's or adjustable <BR>
> vents to control each rad. I saw your <BR>
> earlier post about balancing the venting on the <BR>
> mains. Is this all important, vs. just making <BR>
> sure there is enough venting on each to let the <BR>
> steam move as fast as possible? I guess a lot of <BR>
> this depends on the system itself. Mine cycles <BR>
> on the thermostat, I believe. Its only on for <BR>
> 3-4 minutes at a time. The mains and risers stay <BR>
> pretty hot. Maybe a vaporstat would help there. <BR>
> I would like to lengthen the firing cycle but <BR>
> that big boiler doesn't need to be on long to <BR>
> satisfy the thermostat. Regards. <BR>
<BR>

Boilerpro

Venting and \"unersized boilers\"

Just got Dan's steam school video and workbook and it's got the gray cells churning in a steam way. Steamhead honored me with a visit a few months back and we looked over a big one pipe steam system I've been tuning up. Worked out the main vent sizes for venting the mains completely in one minute. However, I went back and did some figuring on how many btus it would take to get the main up to temp. ...let's say from 90 or 100 to 212. Working with the boiler output per minute it would take about 4 minutes to heat up the main. So my thought was that this is something else that should be taken into account when sizing venting. There seems no sense in putting on vents that can vent 4 times faster than the boiler can produce steam. And, if you think about it, this would also apply to radiators. Maybe vent sizing should be based on air volume and the start up condensing capacity of the pipe, rad, etc.
Also, when sizing vents for rads, I was thinking about sizing them to the heat output needed from that rad on the coldest day of the year, rather than the rad size. We all know that most rads are way too big, so why not tame them this way. And since the rads all fill proportionally to the heating load rather than the rad size, a boiler sized to the heat load, rather than the rad load,would heat the system completely balanced since it will never see the full size of any of the rads...they all vent in proportion to the heat load of the space they are in. The only concern I see then is the piping pick-up... Can we get the steam mains up to temp quickly enough to get the steam to all the rad valves about the same time? I suspect that using very large main vents, and very small rad vents would help this out, as would the fact that the system would have much longer on cycles, than if the boiler was sized to the radiation, which is usualy way, way too big. Some the few systems that I've worked on where the boiler is marginal or undersized according to the radiation, but the rad vents are balanced, it often takes an hour or more for the rads to get hot completely across and the boiler never cycles on the pressuretrol, only the thermostat. If you have an hour to vent the rads completely, very small rad vents are just fine, and the really big vents are on the mains. Just some ideas to churn up Friday Night.

Boilerpro

Boilerpro

Venting and \"unersized boilers\"

Just got Dan's steam school video and workbook and it's got the gray cells churning in a steam way. Steamhead honored me with a visit a few months back and we looked over a big one pipe steam system I've been tuning up. Worked out the main vent sizes for venting the mains completely in one minute. However, I went back and did some figuring on how many btus it would take to get the main up to temp. ...let's say from 90 or 100 to 212. Working with the boiler output per minute it would take about 4 minutes to heat up the main. So my thought was that this is something else that should be taken into account when sizing venting. There seems no sense in putting on vents that can vent 4 times faster than the boiler can produce steam. And, if you think about it, this would also apply to radiators. Maybe vent sizing should be based on air volume and the start up condensing capacity of the pipe, rad, etc.
Also, when sizing vents for rads, I was thinking about sizing them to the heat output needed from that rad on the coldest day of the year, rather than the rad size. We all know that most rads are way too big, so why not tame them this way. And since the rads all fill proportionally to the heating load rather than the rad size, a boiler sized to the heat load, rather than the rad load,would heat the system completely balanced since it will never see the full size of any of the rads...they all vent in proportion to the heat load of the space they are in. The only concern I see then is the piping pick-up... Can we get the steam mains up to temp quickly enough to get the steam to all the rad valves about the same time? I suspect that using very large main vents, and very small rad vents would help this out, as would the fact that the system would have much longer on cycles, than if the boiler was sized to the radiation, which is usualy way, way too big. Some the few systems that I've worked on where the boiler is marginal or undersized according to the radiation, but the rad vents are balanced, it often takes an hour or more for the rads to get hot completely across and the boiler never cycles on the pressuretrol, only the thermostat. If you have an hour to vent the rads completely, very small rad vents are just fine, and the really big vents are on the mains. Just some ideas to churn up Friday Night.

Boilerpro

Bob W._2

your thoughts on steam venting

Hi Dave, it must be getting cool at night because I've started to think about the "system" again. Steamhead suggested master venting my third floor risers and maybe using TRV's (or just 1A's) for control. Those are huge rads, 100 sq. ft. It would have to be about -80 or colder for the rads to get cold all the way across. I plan on using Gorton D's on the vertical mains, just before they go through the 2nd floor ceiling. That will vent them without having to the do the more elegant thing, moving the rads and replacing the valves. Then we can use the TRV's or adjustable vents to control each rad.
I saw your earlier post about balancing the venting on the mains. Is this all important, vs. just making sure there is enough venting on each to let the steam move as fast as possible? I guess a lot of this depends on the system itself. Mine cycles on the thermostat, I believe. Its only on for 3-4 minutes at a time. The mains and risers stay pretty hot. Maybe a vaporstat would help there. I would like to lengthen the firing cycle but that big boiler doesn't need to be on long to satisfy the thermostat. Regards.

Bob W._2

To correct my post, it would have to be -80 or colder for

the rads to get HOT all the way across. Sheesh. Anyhoo, I remain intrigued by your idea of undersizing a boiler and using venting to balance it. Its usuallly cold enough here that the piping would stay pretty warm, which should take it mostly out of the equation. When I replace my 450K with a 300K I'll let you know :-)

Boilerpro

Venting Mains in balance

Well, I'm still finding out... Steamhead does it like this and to me it makes sense. You want the steam to hit the rad valves about the same time throughout the system so you can get balanced heating and one on the ways to do this is to ensure that the amount of steam that moves down each main is in proportion to its volume. If you had big 4 inch main that was 100 feet long and a small 2 1/2 inch main only 50 feet long and you used the same size vent for both, the rads on the small main would get steam way before those on those on the big main. Alot of what I post here on the wall are thoughts about how to maybe do the little steam I get to work on better, so I'm learning lots here too. Yes, nights have been getting down in the 50's and as I said I've been tuning up and old steam system the past few days.

Boilerpro

Boilerpro

Sounds like you've decided to try the \"undersize method\".

I would really like to know how it goes, really cold around here is only 0, so your place must be quite a challenge to heat. I've heard solar is real efective up there.

Boilerpro

Boilerpro

A summary of the above ramble

"Resizing" One pipe steam

Find heat load for each room
Measure rads and type
Size main vents to main volume or time it takes boiler to fill mains at 100F with steam (which ever is smaller)
Size rad vents to the heat load of each room (not rad size) and time it takes boiler to heat rads to the peak output needed (coldest day space needs, not rad size)
Size boiler to heat load of structure (maybe with pick up factor)



Boilerpro

Boilerpro

Is heat anticipator setting right?

> Hi Dave, it must be getting cool at night because

> I've started to think about the "system" again.

> Steamhead suggested master venting my third floor

> risers and maybe using TRV's (or just 1A's) for

> control. Those are huge rads, 100 sq. ft. It

> would have to be about -80 or colder for the rads

> to get cold all the way across. I plan on using

> Gorton D's on the vertical mains, just before

> they go through the 2nd floor ceiling. That will

> vent them without having to the do the more

> elegant thing, moving the rads and replacing the

> valves. Then we can use the TRV's or adjustable

> vents to control each rad. I saw your

> earlier post about balancing the venting on the

> mains. Is this all important, vs. just making

> sure there is enough venting on each to let the

> steam move as fast as possible? I guess a lot of

> this depends on the system itself. Mine cycles

> on the thermostat, I believe. Its only on for

> 3-4 minutes at a time. The mains and risers stay

> pretty hot. Maybe a vaporstat would help there.

> I would like to lengthen the firing cycle but

> that big boiler doesn't need to be on long to

> satisfy the thermostat. Regards.

Boilerpro

Is heat anticipator setting right?

That sounds like a very short thermostat cycle. Anticipator setting for steam is about twice the current draw on stat, or one thermostat cycle per hour, at least as a starting point.

Boilerpro

Bob W._2

Agreed. But I'm not a wethead. How do I know how it is set?

Is is model specific? Please advise. Thanks.

Boilerpro

Advise

If it is an old fashioned thermostat, usually under the cover is a scale marked something like .2 to 1.3 (or so) and usually an arrow pointer with the word longer, Higher numbers give you longer thermotat cycles. For steam, I's set this as high as it can go. If it gets too cold before the het turns on or too hot before it shuts off just move it down to a little lower number until the heating evens out. With newer electronic thermostats, you should find something in the instructions about anticipator setting, cycles per hour setting (cph) or maybe differential. It sould tell you teh proper setting for steam in the instructions. Hope this helps. Getting a longer burn cycle can really help lower fuel bills and cut down wear and tear and the system should heat much more evenly because steam has time to get to all the rads before the burner shuts off.

Boilerpro

Bob W._2

Gee, that might explain things a little....

I have an old Honeywell, not an external switch on it. Anticipator goes from below .10 to 1.2; currently set on just over .2. Maybe needs to go up a little, huh? Thanks. Of course, the house is all masonry and the short cycle does a wonderful job of keeping the thermometer right on the money. Very comfortable. Thanks, Dave.

Boilerpro

Tell me how it efects things when you get a chance

It sounds like your system and boiler are both very oversized and this can make it very hard to control. Changing that anticipator setting is probably going to have a big effect. Was wondering, has there been a heat loss calculation done on you home? What's your square footage per floor, ceiling heights, insulation levels in the walls and ceilings, single or double pane glass, and wall construction for each level...frame, solid masonry, solid masonry with air space behind plaster. You usully can look behind and electrical outlet or switch plate on an outside wall and see into the wall to tell how it is constructed. This is the most basic info. needed to complete a rough heat loss calculation.

Boilerpro

Bob W._2

The best I can guesstimate is about 180K at -30. Different...

formulas yield different results. Remember, this is the house built more like an old school. 3 wythe brick, cavity wall, concrete floors, etc. Lots of old double hungs, with sash weights intact. Good storms. House leaks a lot. Blower door was 9ACH at 50 pascals. I will be air tightening this fall. I will let you know if the change in anticipator setting helps. Looking at installing a vaporstat also if I can find a tech. Regards.

Steamhead

Steam Heat Will Never Die

as long as we're around!

Dave, the way I see it is that while it does take some energy to bring steam mains up to temperature, the boiler is actually steaming at or near full capacity while the mains are venting and warming up. Once this process is complete, it takes much less energy to keep them hot. Since the full boiler capacity is available during main venting it therefore makes sense to accomplish this process quickly- in about a minute, which helps steam to hit all the rad shutoff valves simultaneously. BTW, I didn't come up with the one-minute specification- credit for that goes to Frank Gerety, Steam Philosopher and author of "How to Get the Best from One-Pipe Steam".

Bob, it sounds to me like you're on the right track. If you can't get TRVs my second vent choice is the Vent-Rite #1, which you can adjust without using tools. If the rads continue to overheat, a Vaporstat will help. Let us know how you do!

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