1 or 2 cycles per hour for 1 pipe steam

ChrisJ

PMJ said:

Seems pretty clear that the biggest single trouble with most systems these days is that air gets in the way....at least that is what runaway most of the discussion here is about. The extra effort required to push nearly an entire system volume of air out each and every time the boiler fires just subtracts from the overall efficiency of the delivery system. So now longer burns become the only way to purge air from the far reaches of the system to get some steam there( resulting in longer off periods assuring that you get to start from scratch each and every time). Vacuum, even at low levels, improves both the speed and the eveness of distribution a lot. It is indeed surprising so little effort goes into it.

I'm still waiting for you to convert a single pipe system and prove it can be balanced.

I say it cannot.

Eastman

Why would it be unable to be balanced?

Jamie Hall

You know, one of the most interesting things about steam systems -- one reason I find them so fascinating -- is that every single one is different, and one size, however tenaciously believed in, does not fit all. One needs to approach each one with an open mind...

Fred

Jamie Hall said:

You know, one of the most interesting things about steam systems -- one reason I find them so fascinating -- is that every single one is different, and one size, however tenaciously believed in, does not fit all. One needs to approach each one with an open mind...

So, So true!

ChrisJ

> @Eastman said:
> Why would it be unable to be balanced?

Assuming every radiator matches every room properly it would be. But, that's rarely the case. So, how would you balance them?

PMJ

@ChrisJ,

People have posted on this site who loved their vacuum one pipe systems looking for replacement vacuum vents. They list the same reasons I do for why they like it. Unfortunately they are turned away by those who say vacuum is only for the coal days. Simply not true. They say it about two pipe too. This I know for a fact is not true. Really unfortunate state of affairs for steam heat. A very significant and naturally occurring advantage for steam heat has been lost.

I continue to explore the control possibilities of the naturally sub atmospheric system and they are turning out to be quite significant.

gfrbrookline

I have 7 big mouths and 4 G2's on my system and all of the mains are insulated. I think we just needed a little longer run time to get enough steam to the 3rd floor. They were getting steam just not as much as everyone else.

Zipper13

I just swapped out my old thermostat (which said right in the literature that it was incompatible with steam). found that it was set for forced hot air - 6 CPH.

I set my new one to 1 CPH.

Previously, I would hear it trip on for 5 min at a time and it would take until probably the 3rd or 4th cycle for all rads to start to warm. I'm sure it didn't help that the first rad in the loop is in the same room as the stat. My main is uninsulated so i bet that I lost a lot of progress each time it cycled off and cooled.

Now, at 1CPH, it might run for 30 -60 min every 1-2 hrs depending on where I am in my setback schedule.

I hope to whittle that firing time down after I insulate the main this summer

I've only had the new stat in for maybe 5 days, so I might not have a typical read on the behavior yet since the temps outside have been up and down.

ChrisJ

Zipper13 said:

I just swapped out my old thermostat (which said right in the literature that it was incompatible with steam). found that it was set which was set for forced hot air - 6 CPH.

I set my new one to 1 CPH.

Previously, I would hear it trip on for 5 min at a time and it would take until probably the 3rd or 4th cycle for all rads to start to warm. I'm sure it didn't help that the first rad in the loop is in the same room as the stat. My main is uninsulated so i bet that I lost a lot of progress each time it cycled off and they cooled.

Now, at 1CPH, it might run for 30 -60 min every 1-2 hrs depending on where I am in my setback schedule.

I hope the whittle that firing time down after I insulate the main this summer

I've only had the new stat in for maybe 5 days, so I might not have a typical read on the behavior yet since the temps outside have been up and down.

Can your stat do 2CPH?

Zipper13

@ChrisJ Negative. looks like 3 CPH is the next available. Honeywell RTH7400G

ChrisJ

Zipper13 said:

@ChrisJ Negative. looks like 3 CPH is the next available. Honeywell RTH7400G

What happens if you enter 2, or will it just not do that at all?

You could try 3, but 1 might end up better overall. 3 won't hurt anything.

Zipper13

ChrisJ said:

Zipper13 said:

@ChrisJ Negative. looks like 3 CPH is the next available. Honeywell RTH7400G

What happens if you enter 2, or will it just not do that at all?

You could try 3, but 1 might end up better overall. 3 won't hurt anything.

3 (edit: i mean 2) is not an option. It's been comfortable at 1 CPH, so I can't complain on that front. My main goal is locking down the most efficient option. In addition to my lack of insulation, I assume that pressuretrols have some slop in them so I suspect I'm wasting energy on over pressuring past 1psi.

Gsmith

You might be surprised if you have a 0-3 psi gauge and watch it while the boiler runs. If the boiler is not too oversized, and you have insulated the mains, installed good (copious) main venting and reasonably balanced the roomradiators you may find you do not exceed 0.5 psi except in very cold weather when the boiler has Toruń a long time to satisfy the stat. My boiler and my sons boiler are about about 50% oversized and that’s how both work.

Fred

That's the way mine runs too @Gary Smith.

Gsmith

And some of the reasons are:
Older steam systems had pretty generously sized radiators in each room, improvements to the building envelope have been made over time ( weatherstripping, leak plugging, better windows, attic insulation,etc.), so the radiators can more easily heat the spaces, the radiators don’t need to get hot completely except perhaps on very very cold days and all of the steam is condensed in the time the boiler and rads satisfy the thermostat, long before the pressure builds to the pressure troll cut out.

ChrisJ

Zipper13 said:

ChrisJ said:

Zipper13 said:

@ChrisJ Negative. looks like 3 CPH is the next available. Honeywell RTH7400G

What happens if you enter 2, or will it just not do that at all?

You could try 3, but 1 might end up better overall. 3 won't hurt anything.

3 is not an option. It's been comfortable at 1 CPH, so I can't complain on that front. My main goal is locking down the most efficient option. I addition to my lack of insulation, I assume that pressuretrols have some slop in them so I suspect I'm wasting energy on over pressuring past 1psi.

Why isn't 3 an option?

3 will likely run shorter cycles, which could mean less cycling on pressure, if that's your concern.

ethicalpaul

I think he typo'd a "2" there because he was asked about if 2 was possible

Jamie Hall

Get a T87 and adjust the anticipator until you have it right...

ChrisJ

Jamie Hall said:

Get a T87 and adjust the anticipator until you have it right...

Every time you say that I throw one of our's in the garbage.

Jamie Hall

ChrisJ said:

Jamie Hall said:

Get a T87 and adjust the anticipator until you have it right...

Every time you say that I throw one of our's in the garbage.

Thought I might get a rise out of you on that one, @ChrisJ !

ChrisJ

Jamie Hall said:

ChrisJ said:

Jamie Hall said:

Get a T87 and adjust the anticipator until you have it right...

Every time you say that I throw one of our's in the garbage.

Thought I might get a rise out of you on that one, @ChrisJ !

I was going to take a picture of one with today's newspaper but I can't find a newspaper.

EBEBRATT-Ed

The fewer cph you run and the longer the burn time the better. Temperature swings are the determining factor. No such thing as one size fits all with steam

Canucker

> @ChrisJ said:
> Get a T87 and adjust the anticipator until you have it right...
>
> Every time you say that I throw one of our's in the garbage.

The heatinghelp version of killing kittens...

coelcanth

i hope you do something with the mercury first !

anyway, i love our old T87.. getting the anticipator set right was the key to getting the system perfectly balanced.
can't really see how something so simple could be improved upon.

ChrisJ

coelcanth said:

i hope you do something with the mercury first !

anyway, i love our old T87.. getting the anticipator set right was the key to getting the system perfectly balanced.
can't really see how something so simple could be improved upon.

Calm down, it was a joke.............Just like the kittens @Canucker mentioned.

No old crude thermostats nor kittens were harmed.

mroberts5

On an oversized boiler I'm cutting in and out on pressure at the end of my cycles (running Vaporstat). Reading this got me thinking.

I tried switching from 1 cph to 3. Now the boiler never makes it to pressure. Overall the system is much quieter and the temperatures seem more even. Whats interesting is the radiators never even heat all the way across now - so the vents don't even see steam. Seems like a win?

What are all your thoughts on how this affects efficiency: running once per hour then cycling on pressure, vs running 3 times per hour, for a single run.

PMJ

> @mroberts5 said:
> On an oversized boiler I'm cutting in and out on pressure at the end of my cycles (running Vaporstat). Reading this got me thinking.
>
> I tried switching from 1 cph to 3. Now the boiler never makes it to pressure. Overall the system is much quieter and the temperatures seem more even. Whats interesting is the radiators never even heat all the way across now - so the vents don't even see steam. Seems like a win?
>
> What are all your thoughts on how this affects efficiency: running once per hour then cycling on pressure, vs running 3 times per hour, for a single run.

Bingo. Not "seems like"a win, it is a win @mroberts5. Good thinking indeed.

Efficiency enemy #1 is pressure. Efficiency enemy #2 is air. Eliminate both and you really have something.

dabrakeman

Just interested to know folks opinions on whether more cycles (say 2 instead of 1) would help in an oversized boiler situation?

PMJ

dabrakeman said:

Just interested to know folks opinions on whether more cycles (say 2 instead of 1) would help in an oversized boiler situation?

Yes absolutely. Controlling(adding) cycles easily tames any big boiler and allows running without pressure at all. I've done it for years. Spreads out the burn in smaller pieces, evens out the heat. A better plan all the way around.

ethicalpaul

Gary Smith said:

You might be surprised if you have a 0-3 psi gauge and watch it while the boiler runs. If the boiler is not too oversized, and you have insulated the mains, installed good (copious) main venting and reasonably balanced the roomradiators you may find you do not exceed 0.5 psi except in very cold weather when the boiler has Toruń a long time to satisfy the stat. My boiler and my sons boiler are about about 50% oversized and that’s how both work.

There is so much truth in this short statement. When I first came here I was very concerned about the oversized nature of my boiler, which I calculated to be about 25%-30%.

But since getting my main venting good, replacing my clogged pigtail, re-running a weird sort-of main, and doing a little adjustment to my "header" to reduce wet steam, I have noticed that I sit at about 5 oz during the entire firing cycle, with no cycling on pressure anymore at all. It was kind of like magic.

And I haven't even insulated my mains yet.

Fizz

So miss my Richardson system which I put into vacuum and set t-stat for 3cph. It's smooth, quiet and comfotable heat. I lucked-out as all I did was swap-out Gorton#2's with Mepco Quick vent vacuum vents.
Now I live in house with single pipe, and heat is hot to cool, long runs not the best. Interesting some folks have vacuum vents on single pipe system, but wonder how? Yet Hoffman only makes vacuum vent for single pipe system? Not that it can't be used on 2 pipe, as I have one for back-up on Richardson if buyer is interested.

Jamie Hall

The Hoffman #76 is a vacuum vent originally designed to be the main vent on Hoffman equipped systems. It is still an excellent main vent -- but is limited in capacity (see @gerry gill 's chart) so it may be necessary to use two or three. Which is fine -- if. They are not cheap, so being frugal I'd have to compare the gain in efficiency and hence fuel use to the cost of the vents.

Fizz

True, that's why I went with Mepco Quick vacuum vents.

PMJ

Don't lose sight of the fact that the venting capacity required to run in natural vacuum is dramatically less than what is needed to run open vented. The boiler always fires into the deepest part of the vacuum. Only a very small amount of air needs to be removed at the very end of each burn. The work of removing all that air each and every cycle is eliminated.

ethicalpaul

What vents will hold a vacuum like this? Edit: Or I could learn to read where you guys said Mepco

PMJ

ethicalpaul said:

What vents will hold a vacuum like this? Edit: Or I could learn to read where you guys said Mepco

I am running two pipe so any old check valve on the dry return gets it done. To get to zero back pressure I use a solenoid valve.

Here is some Mepco lit: http://www.mepcollc.com/pdf/literature/steam-specialties/QV-1.pdf

They claim zero cracking pressure - not sure that is possible.

dabrakeman

@PMJ
I will have to try the increased cycles next cold snap. We have had it double digit below zero for a stretch here with wind on top of that. My system runs nicely at even set temperature when outside temps are a little more normal but the severe cold or trying to do setbacks results in pressure build. Most of the winter I won't see more than 0.8oz pressure. On these real cold days the issue is the upstairs bedrooms. I really need these just to take the edge off the cold because we like them cool to sleep anyway. But, when the boiler gets going on those long cycles no matter how much I try to throttle those radiators they still heat up full or near full and get the rooms way to hot. Shorter cycles I can see would prevent this and keep my venting choices for those radiators within maybe something like a Maid-o-Mist #4. In general shorter cycles would allow better balancing of the system to the users taste rather than every radiator eventually filling.

Is there any reasonably priced and decent thermostats that have a 2 cycle per hour option rather than just 1 and 3? Apologize if the answer is somewhere upstream in this thread.

Curious_J

@PMJ What type of control system do you have?

PMJ

@dabrakeman , I wouldn't rely on some mystery logic in an overpriced tstat to control your cycles. I would do it directly with a delay off delay on timer or PLC with just a simple stat calling for heat.

On the upstairs/downstairs thing, I had the same issue in the cold - upstairs warmer than downstairs. In mild weather the opposite. Vacuum is the only thing I know of that really changes that. Evens everything out automatically with no adjusting anything.

Jamie Hall

Well, not the only thing. Cedric manages to keep upstairs and downstairs very even in all temperatures, although wind can make some exposed rooms cold. And I have a simple stat (don't laugh, @ChrisJ !) doing the calling... no other gadgets or whizbangs. Keep it simple!