Dramatic efficiency gained by installing vacuum boost system

MITSailingMaster

Just a couple of months ago we began searching and reading on ways to make our current heating system more efficient. To set the scene, we have a 3000sf home built in 1880 in Massachusetts. Also, we have three generations living together with elder citizens who live with us and like everything as warm as possible.

After research we decided to contact Igor Zhadnovsky and Ed Infantino of A & M Services in Danvers, MA. These guys were very responsive and immediately came out and checked out the current valves, radiators, and efficiency of the oil burner. We have a two pipe system on the ground floor and a single pipe system for the second and third floors. They quoted us on adding the vacuum pumps (2) and piping down from each vent port. It took three days for the full evaluation, install, and final clean up when completed along with a revaluation of efficiency.

Right now we are enjoying a much more even heat in the living areas and the ability to balance individually in the bedrooms upstairs. The elders like it hot, the middller age folks like it cool and the 20 somethings always sleep with the window open. Our house is dramatically more comfortable for everyone. Efficiency has improved with heating costs cut in half with a smaller burner nozzle installed as well. Next month we look forward to converting to a gas nozzle and lowering expenses even further. We couldn't be more pleased with their advice to make our current radiators much more efficient and lower the bill. So, we didn't have to re-do walls behind radiators or anything destructive. Just tie in the 3/8" copper into the vent port on the existing old radiators and Voila!

Call or email Igor and Ed if you're in the New England/ Northeast area. They are thorough and take great pride in doing everything right to make you more comfortable and spend less on heat with your old steam system.

http://forum.heatinghelp.com/discussion/161394/vacuum-boost-retrofit-for-1pipe-and-2-pipe-steam-systems#latest

A&M SERVICES
i.zhadanovsky"

New England SteamWorks

Now. There is a posting that makes a Steam Man proud. It's for postings like that, that we do what we do.

Great work Igor and Ed!

AMservices

Thank you very much. It was a pleasure working in your home. I'm looking forward to coming back for the gas conversion.

Steamhead

Well done.

PMJ

Nice work Igor and Ed.

I also will vouch for the fact that sub-atmospheric operation is far more comfortable and efficient. It also offers more control options - especially in one pipe if you go to the trouble of piping the rad vents to the boiler room as in this example.

The thing is, as far as I can tell, none of this technology is new. Many long since dead men knew very well how to do this. Does anyone have an explanation as to why it disappeared from residential use? Why did Hoffman discontinue the vacuum rad vent for one pipe?

Pumpguy

Can anyone elaborate on exactly what vent valves are used on this application? I am not aware of any currently available rad vent valves that allow for an outlet connection to a vacuum line.

Are these vent valves different from Hoffman Model 3 Paul valves?

AMservices

Forced hot water was cheaper and easier to install. Steam guys couldn't keep up.
But since when is cheaper better. I think the only reason you may run into a steam system that was put in after the war, was thanks to some installers that never viewed hot water as better.
The heating industry stop devoting as much time and resources into systems that nobody was installing.
I believe with this technology, steam guys can make a comeback.
If I took a newly-built house, and designed a low temperature, condensing forced hot water boiler, with radiant floors and thermostats in each room, then took the same house and designed a vacuum steam system, I would bet the steam boiler would be cheaper, with less pipe, less controls, less moving parts and yet.... more balance, more reliable and overall more efficient operation.

Pumpguy said:

Can anyone elaborate on exactly what vent valves are used on this application? I am not aware of any currently available rad vent valves that allow for an outlet connection to a vacuum line.

Are these vent valves different from Hoffman Model 3 Paul valves?

Those are not air vents. They're simple ball valves that are balancing the air we're removing through the radiators.
If a radiator is smaller or closer to the boiler it will heat quicker and we are able to control the air leaving the radiator by balancing the ball valves.

Pumpguy

Interesting....... Just manually adjusted ball valves. Certainly a lot cheaper than Hoffman Model 3 Paul valves.

How difficult was the tuning process? Was there ever a problem with steam carried over into the vacuum lines?

For this particular job, what was the maintained system vacuum range?

AMservices

Short cycling steam through the vacuum lines can be a real problem. When I first started thinking about designing vacuum lines, my first thoughts were " I'm going to need steam traps to keep to steam away from the pump". Igor insisted that they were not necessary. I'm happy to say he was right.
So what I did was run a reverse return system where the vacuum line going back to the pump was coming from the farthest radiators on the main.
In this home there are two vacuum mains. One of the main is much shorter than the other so I knew I would need to balance the air flow through those because air just like water just like Steam will take the path of least resistance.
Back at the vacuum pump manifold where the to vacuum mains meet, there are ball valves to restrict the airflow through the shorter Main.
You can tell when a vacuum Main is getting a stronger flow because those radiators will heat much faster.
After I started the system for the first time, within the first 10 minutes the radiators, off the shoulder steam Maine we're all a third of the way hot, Wild the radiators off the longer Maine, we're only hot at the valve.
All I did was halfway closed the ball valve of the shorter Main, took another walk around and if I founnd radiator was three-quarters of the way hot, While others were only the third to halfway Hot, I would halfway closed the ball valve on that radiator. That's it.
I explained to the homeowner how the ball valves work on the radiators and he was able to adjust the radiators to his liking.

izhadano

> @PMJ said:
> Nice work Igor and Ed.
>
> I also will vouch for the fact that sub-atmospheric operation is far more comfortable and efficient. It also offers more control options - especially in one pipe if you go to the trouble of piping the rad vents to the boiler room as in this example.
>
> The thing is, as far as I can tell, none of this technology is new. Many long since dead men knew very well how to do this. Does anyone have an explanation as to why it disappeared from residential use? Why did Hoffman discontinue the vacuum rad vent for one pipe?

Dear PMJ:
I appreciate very much your personal opinion that "none of this technology is new". Meanwhile, the technology novelty is confirmed by 3 US patents and 1 international with pretty restrict standards on this matter.
Let me use analogy for clarification. With all respect and admiration to The Wright brothers, I can't agree that present day aviation made no breakthroughs. New materials, engines, fuels, controls and concepts changed the flying machine of 1903 into modern air crafts.
So, why don't we see wood airplanes (or Hoffman vacuum rad vent) anymore? - technology evolved into something new.
Thanks,
Igor

PMJ

> @izhadano said:
> > @PMJ said:
> > Nice work Igor and Ed.
> >
> > I also will vouch for the fact that sub-atmospheric operation is far more comfortable and efficient. It also offers more control options - especially in one pipe if you go to the trouble of piping the rad vents to the boiler room as in this example.
> >
> > The thing is, as far as I can tell, none of this technology is new. Many long since dead men knew very well how to do this. Does anyone have an explanation as to why it disappeared from residential use? Why did Hoffman discontinue the vacuum rad vent for one pipe?
>
> Dear PMJ:
> I appreciate very much your personal opinion that "none of this technology is new". Meanwhile, the technology novelty is confirmed by 3 US patents and 1 international with pretty restrict standards on this matter.
> Let me use analogy for clarification. With all respect and admiration to The Wright brothers, I can't agree that present day aviation made no breakthroughs. New materials, engines, fuels, controls and concepts changed the flying machine of 1903 into modern air crafts.
> So, why don't we see wood airplanes (or Hoffman vacuum rad vent) anymore? - technology evolved into something new.
> Thanks,
> Igor

Igor,

I see how my comment might be interpreted as perhaps an attempt to diminish what you have accomplished in your work. It was not intended to be that and I apologize if you were offended. Of course technology is always changing so what I said was not accurate. I should have said that the the concept of using vacuum in steam heating is not new.

What I was meaning to call general attention to was simply the fact that a signicant effort was put into vacuum residential steam very early in the 20th century. The fundamental advantages to the subatmospheric flow of steam in residential systems was well known. My surprise having read some of the old documentation is simply that today the use of vacuum - especially natural vacuum, seems to have largely vanished from residential steam scene entirely. The discussion on the site regarding steam is overwhelmingly about pressure, venting, and the correct way to handle air in and out every cycle. If you are talking about those things you are definitely not talking about vacuum.

I applaud your efforts to bring vacuum back and I'm sure you have taken it to performance levels not previously accomplished. I in no way mean to diminish your accomplishments. I am only observing that on a fundamental level the advantages of vacuum in steam heating have been known for a very long time and for reasons which I don't understand it has largely disappeared from use. I ventured into it reading here that there would be all sorts of mysterious problems - air locks and hung up condensate and the like. I've had nothing of that sort at all - only improved performance in all aspects the deeper the vacuum got.

So I think we are on the same page with vacuum - the difference being that you have taken it much farther than I. I congratulate you and Ed. I think more folks should give it a go.

AMservices

@PMJ
Thank you.

I haven't talked much about my first go around with this vacuum technology.
Probably because no one asked, but mostly because a lot didn't go as planned.
Thankfully that homeowner was somebody willing to take the chance and is the person that got his system running right.
He will bring his story to the forum when he ready.
There can be many problems if your not careful. Shot cycling and sucking water back through the pumps are sum of them... sludge in wet returns can be kicked up and could have you skimming for a week.
And NEVER, EVER PULL A VACUUM ON A BOILER THAT HAS LEAKS!!!



That's what you will get!
And then....





That's what you get.

A simple inspection and a pressure test is the first step making sure a boiler is a candidate for a vacuum.

The worst part about killing that first boiler was we knew it was leaking. The owner found the leaks first and we warned him of the risk. Still decided to load the gun and spin the barrel.

But don't let that scares any of you reading.

The first boiler was piped wrong, had already been leaking, was 40 years old and 50% over sized.

The new boiler works great, the vacuum system is working great to.
This system is in Bangor Maine and has been running all winter with outdoor temperatures 0° to -20°F.

There the right way and a wrong way to do everything in life. Who ever says they did it right the first time is lying.
That's why I started with the second time

BobC

@AMservices You are exactly right, humans learn from their mistakes. The smart ones don't repeat those mistakes - after all there are an infinite selection of mistakes to choose from.

Bob

jumper

Speaking of multistory buildings I speculate that the impetus for HHW was the notion that heating has to work if the pump does. Cheaper when unpaid people do the bleeding and balancing,maybe. Depends on price of monoflo s?

Today I would think that steam heating in multistory buildings ought to be less expensive and more satisfactory. TRV s provide control & balance. Induced vacuum enables smaller tubes. I also like Igor's idea to mount panel high so that radiant/convection ratio is higher.

AMservices said:

Forced hot water was cheaper and easier to install. Steam guys couldn't keep up.
But since when is cheaper better. I think the only reason you may run into a steam system that was put in after the war, was thanks to some installers that never viewed hot water as better.
The heating industry stop devoting as much time and resources into systems that nobody was installing.
I believe with this technology, steam guys can make a comeback.
If I took a newly-built house, and designed a low temperature, condensing forced hot water boiler, with radiant floors and thermostats in each room, then took the same house and designed a vacuum steam system, I would bet the steam boiler would be cheaper, with less pipe, less controls, less moving parts and yet.... more balance, more reliable and overall more efficient operation.

izhadano

PMJ said:

> @PMJ said

I see how my comment might be interpreted as perhaps an attempt to diminish what you have accomplished in your work. It was not intended to be that and I apologize if you were offended. Of course technology is always changing so what I said was not accurate. I should have said that the the concept of using vacuum in steam heating is not new.
==================================
Peter,
sorry, - I've overreacted. Just sick and tired to hear that nothing new can be evolved from steam/vacuum heating. At the very beginning of my quest some top brass at ASHRAE flatly recommended to drop the subject and proceed with something meaningful and the I've heard the same stuff from many "green" gurus.
As it said by Stephen Hawking "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge".
Yes, we're on the same page.
Igor

hvacfreak2

Man this is fascinating . If this didn't involve the piping to the spaces I'd be buying some pumps .

How about tapping the vacuum lines right at the base of each riser ? It would require vacuum vents on the radiators to vent the remaining air as the steam moves forward but I'm thinking it ( amount of air ) would be minimal. It is a compromise from the ideal but it would keep everything downstairs. Thoughts or experiences with anything similar to this ?

AMservices

> @BobC said:
> @AMservices You are exactly right, humans learn from their mistakes. The smart ones don't repeat those mistakes - after all there are an infinite selection of mistakes to choose from.
>
> Bob

> @hvacfreak2 said:
> Man this is fascinating . If this didn't involve the piping to the spaces I'd be buying some pumps .
>
> How about tapping the vacuum lines right at the base of each riser ? It would require vacuum vents on the radiators to vent the remaining air as the steam moves forward but I'm thinking it ( amount of air ) would be minimal. It is a compromise from the ideal but it would keep everything downstairs. Thoughts or experiences with anything similar to this ?

That was a learning lessons we got on the first system we installed.
First, you can't take enough air out to fill the entire system tapping the line before the radiators.
The pump needs to come on to start removing the air, when we reach our desired vacuum level it shuts off, then the steam starts filling the system and the remaining air in the system starts compressing into the radiator. When that happens the compressed air lowers the vacuum level in the vacuum lines and the pump turns back on the evacuate the rest of the air.
Second, tapping the vacuum line into the pipe turns the line into a straw that will suck condensate into the line. Not good.

hvacfreak2

The pump needs to come on to start removing the air, when we reach our desired vacuum level it shuts off, then the steam starts filling the system and the remaining air in the system starts compressing into the radiator. When that happens the compressed air lowers the vacuum level in the vacuum lines and the pump turns back on the evacuate the rest of the air.

Second, tapping the vacuum line into the pipe turns the line into a straw that will suck condensate into the line. Not good.

Thank you , understood. Traps , drips , control sequence for that pesky condensate for sure.

nicholas bonham-carter

On a cold start, the pump would come on as the boiler is heating up.
On a two-pipe system, all the air would be evacuated down to the level of desired vacuum, as the traps are open.
One a one-pipe system, there are no traps, so the pump may inhale steam, if there is no way to cut the pump off, as steam is rising. Maybe traps on the vacuum ventline would provide protection, or condensers.
On non pumped two-pipe systems, the air is pushed out of the boiler, supplies, and radiators, but remains in the returns, and this is where the vacuum pump improves the performance.
A large header could act as a vacuum reservoir in non-pumped systems.
Maybe some sort of control to delay the firing of the boiler would be useful, to wait until the proper vacuum level is attained.--NBC

Paul48

It might be worthwhile to talk with @Sailah about the possibility of adapting a trap for use as a radiator vac/vent. I don't know whether it's even possible against vacuum, but if it's do-able he can figure it out. I know he's told me that he has adapted a trap to control a switch.

AMservices

Paul48 said:

It might be worthwhile to talk with @Sailah about the possibility of adapting a trap for use as a radiator vac/vent. I don't know whether it's even possible against vacuum, but if it's do-able he can figure it out. I know he's told me that he has adapted a trap to control a switch.

Hoffman makes paul's system air vent that works. The problem is is there expensive.
And I believe @izhadano had problems with them when he was first testing his system.

nicholas bonham-carter said:

On a cold start, the pump would come on as the boiler is heating up.
On a two-pipe system, all the air would be evacuated down to the level of desired vacuum, as the traps are open.
One a one-pipe system, there are no traps, so the pump may inhale steam, if there is no way to cut the pump off, as steam is rising. Maybe traps on the vacuum ventline would provide protection, or condensers.
On non pumped two-pipe systems, the air is pushed out of the boiler, supplies, and radiators, but remains in the returns, and this is where the vacuum pump improves the performance.
A large header could act as a vacuum reservoir in non-pumped systems.
Maybe some sort of control to delay the firing of the boiler would be useful, to wait until the proper vacuum level is attained.--NBC

We have consider delaying the burner and allow the vacuum pump to do its thing first.
With 4 CFM pump in a system with under a 1000 square feet EDR, we are at 15 HG in under 3 minutes ( this would depend on how mini leaks are present in the system).
Within five minutes you can feel the heat entering the first sections of the radiator.

We do use a hi-limit to protect the pump from Steam, use the vacuum Mains as condensers for the steam along with the steam separator, then as a last line of defense, have a thermostatic trap that will spring-shut if steam hits it.
Protecting the pump is everything!
Sucking air is easy.

We're trying to remove as many small moving Parts as we can.
But from what I've seen no two steam systems are the same.
I know that in certain situations, the time will come when it's the best solution to a short cycling problem.
In that case I would love to know what trap @Sailah would recommend?
To work with as much as 20 inches of mercury on the return side and fluctuating temperatures on the inside?
I too was thinking if there was a thermostatic radiator valve for the supply side of the radiator and the temperature sensing bulb could be on the return pipe then adjusted to open and close as it senses Steam trying to enter the dry return. Not sure if that would be possible. The radiator valve would have to close quickly I think?

Paul48

@AMservices
The great thing about @Sailah , is, he'll work with you. He might see it as another "Bigmouth" type challenge. Do those Hoffman vents provide for a means of vacuum applied at the radiator?

PMJ

For what it is worth I have found that the first cycle evacuation of air is really a non-issue altogether and might as well be done for free. The slow part about the first cold start is heating up pipes not removing air. Remember during the times you actually need heat there are very few first cold cycles anyway.

It would surprise me a lot if in one pipe the air won't just go out the vent lines running to the basement easily on its own during the first slower warmup. If you have pumps installed obviously just run them but if someone was looking to get started in one pipe just with natural vacuum I think it would work fine. Like I have written before, I have only a 1/2" opening in my dry return for all 1000EDR (24 rads) and don't hear a thing coming out of it during my first cycle from dead cold start of say 25 minutes burn.

Better yet though a reasonably priced rad vacuum vent for one pipe would be the best way to start out. @Sailah?

AMservices

The Paul's system was a mechanical vacuum system that used a type of ejector instead of a pump. I haven't used them, I just know they failed Igor's test.
In a 1 pipe system, if you are to go through the trouble of running air lines from the radiators to the basement, you still need a solenoid valve or main air vent, still need to build pressure.... why wouldn't you want a pump to help the process move quicker?
The steam is larger under vacuum, moving faster, from a dead cold start it take 5 minuts to feel steam at the valves and is filling the system at lower then 212°.
Reducing start up losses is huge! and then another option is to run the pump at the end of the heat cycle, to pull the reminding heat out of the boiler.

PMJ

AMservices said:

The Paul's system was a mechanical vacuum system that used a type of ejector instead of a pump. I haven't used them, I just know they failed Igor's test.
In a 1 pipe system, if you are to go through the trouble of running air lines from the radiators to the basement, you still need a solenoid valve or main air vent, still need to build pressure.... why wouldn't you want a pump to help the process move quicker?
The steam is larger under vacuum, moving faster, from a dead cold start it take 5 minuts to feel steam at the valves and is filling the system at lower then 212°.
Reducing start up losses is huge! and then another option is to run the pump at the end of the heat cycle, to pull the reminding heat out of the boiler.

My only question about this is how startup losses can be a very big factor when there are so few of them when heat is actually needed. My 25 minute example almost never happens.

I get that if I pumped my system down first steam would get out there faster on that first cycle. It is just that the way I run there are so few first cycles I don't care really. I'm not arguing that your way is not better, it is just that what you get with no extra equipment at all is really quite significant.

AMservices

My only question about this is how startup losses can be a very big factor when there are so few of them when heat is actually needed. My 25 minute example almost never happens.

I get that if I pumped my system down first steam would get out there faster on that first cycle. It is just that the way I run there are so few first cycles I don't care really. I'm not arguing that your way is not better, it is just that what you get with no extra equipment at all is really quite significant.

I agree entirely.
During this installation after we completed running the vacuum lines, I was tempted to try running the system without the pump just to see how it would work.
Never a chance to. Too busy trying to finish the other ends of the job.

PMJ

> @AMservices said:
> My only question about this is how startup losses can be a very big factor when there are so few of them when heat is actually needed. My 25 minute example almost never happens.
>
> I get that if I pumped my system down first steam would get out there faster on that first cycle. It is just that the way I run there are so few first cycles I don't care really. I'm not arguing that your way is not better, it is just that what you get with no extra equipment at all is really quite significant.
>
> I agree entirely.
> During this installation after we completed running the vacuum lines, I was tempted to try running the system without the pump just to see how it would work.
> Never a chance to. Too busy trying to finish the other ends of the job.

I see. Maybe try it someday.

Also, I am assuming your systems are always sub atmospheric right - even when the boiler is firing? How are you controlling the firing time then?

izhadano

PMJ said:

AMservices said:

The Paul's system was a mechanical vacuum system that used a type of ejector instead of a pump. I haven't used them, I just know they failed Igor's test.
In a 1 pipe system, if you are to go through the trouble of running air lines from the radiators to the basement, you still need a solenoid valve or main air vent, still need to build pressure.... why wouldn't you want a pump to help the process move quicker?
The steam is larger under vacuum, moving faster, from a dead cold start it take 5 minuts to feel steam at the valves and is filling the system at lower then 212°.
Reducing start up losses is huge! and then another option is to run the pump at the end of the heat cycle, to pull the reminding heat out of the boiler.

My only question about this is how startup losses can be a very big factor when there are so few of them when heat is actually needed. My 25 minute example almost never happens.

I get that if I pumped my system down first steam would get out there faster on that first cycle. It is just that the way I run there are so few first cycles I don't care really. I'm not arguing that your way is not better, it is just that what you get with no extra equipment at all is really quite significant.

Paul,
Recently I was surprised to learn that our body creates 1-1.5 psig pressure while breathing out and ~15Hg (7.5 psi negative) while breathing in, - 5-7 fold difference in created pressure drop because nature (atmospheric pressure) is working for us on later one!
That's seems to me a fair analogy of cold start of steam system with naturally induced vacuum while purging air versus cold start of steam system with vacuum boost.
Also, it's very difficult to push out air from all parts of the steam system simultaneously through single (2? 3?) vent(s); any air left in a system will play against you later on. Balancing air purging would be a challenge especially for big systems.
The low importance of cold start also seems to me an underestimated factor. From the total heat load, really cold weather contribute for only ~35% (NY/Boston area - DOE/CARB data). So, for the rest 65%, the cold start might be the only one cycle employed with significant overkill in temperature of vapor supplied and balancing problem of heat distribution.
Again, that's my personal opinion and it may be wrong
Thanks,
Igor

PMJ

izhadano said:

Paul,
Recently I was surprised to learn that our body creates 1-1.5 psig pressure while breathing out and ~15Hg (7.5 psi negative) while breathing in, - 5-7 fold difference in created pressure drop because nature (atmospheric pressure) is working for us on later one!
That's seems to me a fair analogy of cold start of steam system with naturally induced vacuum while purging air versus cold start of steam system with vacuum boost.
Also, it's very difficult to push out air from all parts of the steam system simultaneously through single (2? 3?) vent(s); any air left in a system will play against you later on. Balancing air purging would be a challenge especially for big systems.
The low importance of cold start also seems to me an underestimated factor. From the total heat load, really cold weather contribute for only ~35% (NY/Boston area - DOE/CARB data). So, for the rest 65%, the cold start might be the only one cycle employed with significant overkill in temperature of vapor supplied and balancing problem of heat distribution.
Again, that's my personal opinion and it may be wrong
Thanks,
Igor

Igor,

I can only speak from lots of experience now with natural vacuum. Maybe it is a 2 pipe thing but I have no trouble getting steam to all rads fairly equally on that first cold start. From there, since the system spends most of the time (75-80%) in vacuum I find that the rads in the coldest places condense more steam than those in warmer places and the system evens out the heat automatically. I have no issues at all with air trapped anywhere. Things get better and better as my cycles progress (3/hour) and I don't find the results of the first cycle very significant at all.

Beyond that, I still have some vacuum some 3-4 hours after last fire and a boiler still quite warm so a start up cycle even in milder weather might have a preheat time of 3-4 minutes before the sensor on the main shows hot again.

Again, I am not offering these things to diminish in any way the results of your approach. I have found the more vacuum the better and I am sure you have more vacuum than I do with your pumps and your results are better than mine. I am simply offering up my experience in the hope that more folks will try vacuum. Going all the way to pumps and vent lines is a pretty big step for most people. I am suggesting that there are ways to venture in with smaller steps. I am saying that every little bit of vacuum helps - it is definitely not an all or nothing thing. I do believe one vacuum vent on only one rad in a one pipe system will effectively cause that rad to grab a higher percentage of the steam condensed by the whole system than it would with the regular vent.

AMservices

@PMJ
I appreciate your questions and understand what you're saying. Converting a steam system to run with a naturally or mechanically induced vacuum is a good way to improve any system. I'm sure people would see savings as long as it was able to be controlled and balanced.

Having a pump relives the system from having to do that extra work pushing air and there will be a quicker turn around on your investment.
Paul's system was a retrofit for large 1 pipe system. They would typically see a 35% reduction in there annual fuel spending.

From what I've read about vacuum vents with Check valves, there not as reliable and fairly expensive.

The vacuum pump we're using and the run time it would see in a average new England winter, the manufacturer would give it a 30 year life expectancy. Oil free, no maintenance.

To replace all the vents on a 1 pipe system with vacuum vents would be more then the cost of the pump for sure.

As for how we control this system, we keep it simple.
The pump is controlled with a vacuum switch and hi-limit, the boiler is still using a vaporstat.
Everything Heats up so fast, the boiler shuts off before it build pressure.
We keep the boiler with the ability to make a few ounces of pressure in the event arctic temperature come through, the system will still run as originally designed.
Every system is different and depending on a lot of variables, a different home with a different systems might benefit with a different control setup.

Sailah

Was busy with my stupid bathroom remodel. Grrrrrr.

I had to go machine something and then weld a little stainless to get things right in the world.

I haven't been totally following this thread if someone wants something describe in detail and I'll see what I can do.

Our thermostatic steam traps operate from vacuum to 25PSIG for low pressure. We seal them under about 24" vacuum so they should work in your system. I know other manufacturers don't do this so not all traps are balanced pressure.

I really wish I had a steam system. I could totally geek out with it. If I did I'd be focusing on a Raspberry Pi microcontroller with vacuum and solenoid actuators.

Sailah

I did turn a steam trap into a switch. Was a little labor intensive to make but it works fine. Ran it for months until we decided to build our own ultrasonic steam trap monitoring system. It was really accurate too.

We ran a circuit of AC voltage through the cage unit at a high frequency something like 100kHz. I could see on my data log about 5 seconds before the trap would open.

The Pi controlled this circuit in addition to temp data logging as well as the steam solenoid feeding 3 radiators we were using a test mules.

I was up on the mezzanine of our factory all last winter working on it. Every day, weekends. I miss it actually. But our new monitors work so much better so it was worth it.

Sailah

Hey @MITSailingMaster

What's your boat of choice?

AMservices

@Sailah
Our thermostatic steam traps operate from vacuum to 25PSIG for low pressure. We seal them under about 24" vacuum so they should work in your system. I know other manufacturers don't do this so not all traps are balanced pressure.

I really wish I had a steam system. I could totally geek out with it. If I did I'd be focusing on a Raspberry Pi microcontroller with vacuum and solenoid actuators.


The job I looked at yesterday might be the perfect test for it.
Igor wants to test the Raspberry too.
The job is a 2 pipe system with fan coil and some fin tube baseboard.
The entire system is a mess.
I want to try zoning it and modulate the burner.
When I get more information and figure out exactly what I want to do, I'll contact you for more control options.
Thank you

BobC

@AMservices Do you have any information on what the runtime on the vacuum pumps would be in the coastal NE? Also what is the rough power draw of the pump in watts?

Bob

Sailah

> @AMservices said:
> @Sailah
> Our thermostatic steam traps operate from vacuum to 25PSIG for low pressure. We seal them under about 24" vacuum so they should work in your system. I know other manufacturers don't do this so not all traps are balanced pressure.
>
> I really wish I had a steam system. I could totally geek out with it. If I did I'd be focusing on a Raspberry Pi microcontroller with vacuum and solenoid actuators.
>
>
> The job I looked at yesterday might be the perfect test for it.
> Igor wants to test the Raspberry too.
> The job is a 2 pipe system with fan coil and some fin tube baseboard.
> The entire system is a mess.
> I want to try zoning it and modulate the burner.
> When I get more information and figure out exactly what I want to do, I'll contact you for more control options.
> Thank you

If you do decide to go with raspberry pi please let me know. I don't know where you are on the learning curve but I can probably speed you up with some of the work I've done and files I had my developer code up to run it all. I still have mine set up sorta.

I would probably introduce you to my developer as well. He's very reasonable about these things and very knowledgeable. In fact he's working on something very similar for my boss with anther company. They redesigned the entire vari vac vacuum control system and built a discrete control using LoRaWAN radio to control large vacuum heating systems in public housing in NYC. Doing a single family unit using Pi I bet would be a snap.

If you could give me how you envision the system working from a control standpoint I'll run it by him to see what would be involved.

AMservices

Igor knows better about run time.
The pumps can work with 120 or 240 volts, 450 watts, 3.8 / 1.8 amp draw.
Wiring 240v is more efficient.
The pump will come on and off several times during a cycle. For how long will depend on the size of the system and how bad it's leaking.
For @MITSailingMaster, to go from 0 to 15 Hg
Takes 5 minutes, is off for roughly 10 minutes, comes back on 4 minutes. As the system is filling with steam there is less air that the pump needs to remove, so the runtime decreases through the cycle. When steam finally gets to the pump, the high limit prevent it from running.
There are several ways that we can change the run time on pump by adjusting the controls.

I'm sure the more installations I do, the better options for controlling the system I will find.
For now keeping it simple works.

PMJ

AMservices said:

@PMJ
I appreciate your questions and understand what you're saying. Converting a steam system to run with a naturally or mechanically induced vacuum is a good way to improve any system. I'm sure people would see savings as long as it was able to be controlled and balanced.

Having a pump relives the system from having to do that extra work pushing air and there will be a quicker turn around on your investment.
Paul's system was a retrofit for large 1 pipe system. They would typically see a 35% reduction in there annual fuel spending.

From what I've read about vacuum vents with Check valves, there not as reliable and fairly expensive.

The vacuum pump we're using and the run time it would see in a average new England winter, the manufacturer would give it a 30 year life expectancy. Oil free, no maintenance.

To replace all the vents on a 1 pipe system with vacuum vents would be more then the cost of the pump for sure.

As for how we control this system, we keep it simple.
The pump is controlled with a vacuum switch and hi-limit, the boiler is still using a vaporstat.
Everything Heats up so fast, the boiler shuts off before it build pressure.
We keep the boiler with the ability to make a few ounces of pressure in the event arctic temperature come through, the system will still run as originally designed.
Every system is different and depending on a lot of variables, a different home with a different systems might benefit with a different control setup.

@AMservices ,

So if I am understanding your control correctly, you do run the boiler each cycle to a very low pressure setting on the vaporstat meaning all the vacuum is gone when the boiler shuts off for a very brief moment in the cycle right?

That being the case, your cycle is very similar to mine except that I don't use the vaporstat at all and your deepest vacuum with pumps will be more than mine and your time above atmospheric shorter (currently my time above is around 25%). I would expect better performance than I am getting - how much is unknown at this point. My equipment to get this far is a low end PLC, a solenoid valve, a pressure switch, and a temperature switch on the main to get a longer preheat run for colder starts when needed. Not much equipment to keep track of and no additional valves to adjust. But then a 2 pipe vacuum retrofit is considerably easier. If I were to put a pump on the dry return it could be anywhere and I would have no concern at all about steam getting to it. If it weren't for the noise I'd do it now.

PMJ

AMservices said:

Igor knows better about run time.
The pumps can work with 120 or 240 volts, 450 watts, 3.8 / 1.8 amp draw.

What we could use is a rough estimate of percent on time of total elapsed time or total hours per day would work too. Pump is about .5KW so we if could know about how many KWhours/month we could estimate energy cost.

AMservices

The runtime you would expect to see with the pump is relative to what temperature is outside, the set temperature on the thermostat, how you choose two adjust the control components.
No two steam systems are the same.
If I had to give a ballpark estimate on how much run time a pump would see during the coldest days of the winter, I would estimated to be between three and four hours a day.
Even though we leave the boiler with the ability to build pressure, it almost never happens

jumper

The way I remember old Toronto manually controlled vacuum systems is that they were evacuated only periodically. Perhaps once a day when it was very cold,otherwise not for weeks. After all most steam heating doesn't even have any vacuum generator.

With respect to the two pipe question,the one building that used single connection to convectors was the troublesome one.