Single pipe vacuum balancing

Gsmith

@acwagner: yes that was it, thank you!

ethicalpaul

Gary Smith said:

@ethicalpaul and @acwagner : I too have been interested in converting my one pipe steam system to vacuum if I can find a simple and reliable way to do it. You might look into Generant DiscValves which have a very low cracking pressure (they claim 1" water column which is about 0.036 psi or about 0.5 oz/sq. in. I've been thinking of trying them attached to a clear vinyl hose clampted to the outlet of a standard radiator valve so they don't see steam pressure (they claim 212 deg F as max operating temperature). I haven't priced the whole assembly but think it might be pretty pricey, but maybe in total on a par with running small diameter vacuum lines from each radiator to a central control area. Attached is a cut sheet from Generant (made in NJ)

Ha! they are about 30 minutes from my house. I guess I could drop in and say hi!

ChrisJ

ethicalpaul said:

Gary Smith said:

@ethicalpaul and @acwagner : I too have been interested in converting my one pipe steam system to vacuum if I can find a simple and reliable way to do it. You might look into Generant DiscValves which have a very low cracking pressure (they claim 1" water column which is about 0.036 psi or about 0.5 oz/sq. in. I've been thinking of trying them attached to a clear vinyl hose clampted to the outlet of a standard radiator valve so they don't see steam pressure (they claim 212 deg F as max operating temperature). I haven't priced the whole assembly but think it might be pretty pricey, but maybe in total on a par with running small diameter vacuum lines from each radiator to a central control area. Attached is a cut sheet from Generant (made in NJ)

Ha! they are about 30 minutes from my house. I guess I could drop in and say hi!

You could.
Never know, they might offer a sample or two for testing for the application.

PMJ

ChrisJ said:

PMJ said:

ChrisJ said:

PMJ said:

You have said multiple times there are several people doing it successfully.

Not so - didn't say that. I know of at least one poster from several years back who loved his one pipe vacuum system looking for replacement Hoffman valves who was told one pipe vacuum doesn't work. Don't have it handy. Search the site.

My position that this is possible is based on Hoffman. Please read that. You keep assigning the whole thing to me.

PMJ said:

@chrisj,

Everyone always defaults to the idea that one pipe vacuum valves were only for coal fired systems and primarily a once end of day thing when the fire dies down.

I have attached a Hoffman document I am sure everyone has seen which talks about one pipe vacuum systems using their vacuum valve. It says it is also for oil and gas systems saying it will cut down the number of operations per day. Cycles anyone?

Beyond this look for posts of happy one-pipe vacuum system users on this site who obviously are running cycling systems. There aren't many. They get turned away here quickly.

So please, let's get started on the right foot. It is not my hypothesis. I know from first hand experience that natural vacuum in cycling two pipe is a wonderful improvement. From the literature is seems Hoffman thought it was in one-pipe too. They called it "Locking the door against the heat thief".

Maybe I misunderstood.

My apologies Chris. I admit to a small embellishment there. I did say there aren't many did I not?

However, just to show it is not totally made up here is one:
https://forum.heatinghelp.com/discussion/66051/vacuum-vent-valves-for-steam-radiators

A long time ago, yes, but it my opinion this fellow has it exactly right. He lists the same things he likes about the vacuum I do and Hoffman describes. The reception shows why they're aren't many here and won't be.

@PMJ
I do not see anyone being disrespectful in that thread.
@Steamhead Was giving what he believed to be sound advice.

I also do not see any indication that the OP's system had been running in a vacuum. It sounded like he was trying to restore it's vacuum operation and that the vents were likely all leaky.

The benefits he says sounds like he's quoting sales literature.

Good heavens! Are we reading the same things? Where did I suggest anything about disrespect?

The poster was simply told that vacuum really can't work if you don't get all the air out and what he was seeing meant his system had a basic problem - like air chasing collapsing steam back to the boiler..... which is what it does in open vented systems. He clearly was just trying to restore the performance he previously had and was now lost due to leaking vents. That is plenty clear. His rads cooled off quickly when the boiler went off now and didn't before.

I said nothing about @Steamhead being disrespectful. I have no problem with people stating what they truly think. I'm not always right about everything either. In this case, however, I agree with the poster about what he was seeing. Perhaps that is just because I am one of the apparently very very few who has actually experienced this myself.

The conventional wisdom here clearly is that it doesn't work and that requires that Hoffman was wrong about it. That is your stated position too. I'm siding with Hoffman and my own experience.

ChrisJ

I'm

PMJ said:

ChrisJ said:

PMJ said:

ChrisJ said:

PMJ said:

You have said multiple times there are several people doing it successfully.

Not so - didn't say that. I know of at least one poster from several years back who loved his one pipe vacuum system looking for replacement Hoffman valves who was told one pipe vacuum doesn't work. Don't have it handy. Search the site.

My position that this is possible is based on Hoffman. Please read that. You keep assigning the whole thing to me.

PMJ said:

@chrisj,

Everyone always defaults to the idea that one pipe vacuum valves were only for coal fired systems and primarily a once end of day thing when the fire dies down.

I have attached a Hoffman document I am sure everyone has seen which talks about one pipe vacuum systems using their vacuum valve. It says it is also for oil and gas systems saying it will cut down the number of operations per day. Cycles anyone?

Beyond this look for posts of happy one-pipe vacuum system users on this site who obviously are running cycling systems. There aren't many. They get turned away here quickly.

So please, let's get started on the right foot. It is not my hypothesis. I know from first hand experience that natural vacuum in cycling two pipe is a wonderful improvement. From the literature is seems Hoffman thought it was in one-pipe too. They called it "Locking the door against the heat thief".

Maybe I misunderstood.

My apologies Chris. I admit to a small embellishment there. I did say there aren't many did I not?

However, just to show it is not totally made up here is one:
https://forum.heatinghelp.com/discussion/66051/vacuum-vent-valves-for-steam-radiators

A long time ago, yes, but it my opinion this fellow has it exactly right. He lists the same things he likes about the vacuum I do and Hoffman describes. The reception shows why they're aren't many here and won't be.

@PMJ
I do not see anyone being disrespectful in that thread.
@Steamhead Was giving what he believed to be sound advice.

I also do not see any indication that the OP's system had been running in a vacuum. It sounded like he was trying to restore it's vacuum operation and that the vents were likely all leaky.

The benefits he says sounds like he's quoting sales literature.

Good heavens! Are we reading the same things? Where did I suggest anything about disrespect?

The poster was simply told that vacuum really can't work if you don't get all the air out and what he was seeing meant his system had a basic problem - like air chasing collapsing steam back to the boiler..... which is what it does in open vented systems. He clearly was just trying to restore the performance he previously had and was now lost due to leaking vents. That is plenty clear. His rads cooled off quickly when the boiler went off now and didn't before.

I said nothing about @Steamhead being disrespectful. I have no problem with people stating what they truly think. I'm not always right about everything either. In this case, however, I agree with the poster about what he was seeing. Perhaps that is just because I am one of the apparently very very few who has actually experienced this myself.

The conventional wisdom here clearly is that it doesn't work and that requires that Hoffman was wrong about it. That is your stated position too. I'm siding with Hoffman and my own experience.

I'm sorry @PMJ but I took your comments about people being turned away as a bad thing.

I see no indication that the OP actually experienced anything. Like I said, it sounded like he was trying to restore something he never had.

So,
What's the story with the Paul system?

PMJ

ChrisJ said:

PMJ said:

ChrisJ said:

PMJ said:

You have said multiple times there are several people doing it successfully.

Not so - didn't say that. I know of at least one poster from several years back who loved his one pipe vacuum system looking for replacement Hoffman valves who was told one pipe vacuum doesn't work. Don't have it handy. Search the site.

My position that this is possible is based on Hoffman. Please read that. You keep assigning the whole thing to me.

PMJ said:

@chrisj,

Everyone always defaults to the idea that one pipe vacuum valves were only for coal fired systems and primarily a once end of day thing when the fire dies down.

I have attached a Hoffman document I am sure everyone has seen which talks about one pipe vacuum systems using their vacuum valve. It says it is also for oil and gas systems saying it will cut down the number of operations per day. Cycles anyone?

Beyond this look for posts of happy one-pipe vacuum system users on this site who obviously are running cycling systems. There aren't many. They get turned away here quickly.

So please, let's get started on the right foot. It is not my hypothesis. I know from first hand experience that natural vacuum in cycling two pipe is a wonderful improvement. From the literature is seems Hoffman thought it was in one-pipe too. They called it "Locking the door against the heat thief".

Maybe I misunderstood.

My apologies Chris. I admit to a small embellishment there. I did say there aren't many did I not?

However, just to show it is not totally made up here is one:
https://forum.heatinghelp.com/discussion/66051/vacuum-vent-valves-for-steam-radiators

A long time ago, yes, but it my opinion this fellow has it exactly right. He lists the same things he likes about the vacuum I do and Hoffman describes. The reception shows why they're aren't many here and won't be.

@PMJ
I do not see anyone being disrespectful in that thread.
@Steamhead Was giving what he believed to be sound advice.

I also do not see any indication that the OP's system had been running in a vacuum. It sounded like he was trying to restore it's vacuum operation and that the vents were likely all leaky.

The benefits he says sounds like he's quoting sales literature.

I see. So the figures he quoted 20-30 minutes more of warm radiators and 25" of vacuum came from sales literature. I stand with my position it was his own experience.

I'm comfortable that there is enough data here now for everyone to draw their own conclusions about this.

jumper

Fizz said:

So, if you put vacuum vent(s) at end of return on one pipe system, would this cause vapor lock? Also, could it put boiler in vacuum causing low temp steam potential? What's worse case scenario?

I believe that trapped air has been blamed for condensate not descending. Water vapor lock doesn't make sense to me.

SteamCoffee

I think the main problem is 1 pipe vacuum was a relatively short lived process, the evolution to 2 pipe and its various forms kind of left it in the dust of progress. Over time, Once vacuum vents started to fail, and the lack of easy replacements, lack of technicians who understood it nuances etc., made it a rather small cross section of the then huge steam heating market. Single pipe vacuum, either installed from new or more than likely retrofitted, is a sound principal. I can’t imagine a reputable company like Hoffman or Dunham “selling” a system that didn’t benefit from their excellent, then cutting edge, engineering departments. That being said, I can’t imagine how the benefits they extoll both in their respective company “sales brochures “ or in the engineering textbooks of they day, would produce anything other than very satisfactory results. The bridge between salesmanship and engineering was almost always filled with the skill of experienced hands and the sweat of their brow. That knowledge is sadly, irretrievably, gone but waiting to be rediscovered. This may be the only place on the planet that this could happen....please keep discussing it....with an open, curious mind

PMJ

jumper said:

Fizz said:

So, if you put vacuum vent(s) at end of return on one pipe system, would this cause vapor lock? Also, could it put boiler in vacuum causing low temp steam potential? What's worse case scenario?

I believe that trapped air has been blamed for condensate not descending. Water vapor lock doesn't make sense to me.

None of these things make any sense.

If you keep air out when the burner goes off all that happens is that the whole system simply drops to a lower (below atmospheric) pressure. But the pressure relationships between the header and the rads stays the same, even as the system as a whole drops further and further into negative territory. Because the rads are not allowed to fill with air from the room, the void being created there( the lowest pressure in the whole system by a very small amount) continues to be filled by steam from the mains, and the boiler continues to make a small amount of new steam with the burner off due to the drop in system pressure. But there is no significant change in any of the relationships inside the system. There is no trapping or holding up of anything. Gravity is still gravity and condensate runs as normal.

If air is not let in when the burner goes off the system just continues doing what it was doing...delivering steam to the rads. The amount delivered tapers down to a stop and the system then sits in a place much easier to restart without all that air to remove.

PMJ

SteamCoffee said:

I think the main problem is 1 pipe vacuum was a relatively short lived process, the evolution to 2 pipe and its various forms kind of left it in the dust of progress. Over time, Once vacuum vents started to fail, and the lack of easy replacements, lack of technicians who understood it nuances etc., made it a rather small cross section of the then huge steam heating market. Single pipe vacuum, either installed from new or more than likely retrofitted, is a sound principal. I can’t imagine a reputable company like Hoffman or Dunham “selling” a system that didn’t benefit from their excellent, then cutting edge, engineering departments. That being said, I can’t imagine how the benefits they extoll both in their respective company “sales brochures “ or in the engineering textbooks of they day, would produce anything other than very satisfactory results. The bridge between salesmanship and engineering was almost always filled with the skill of experienced hands and the sweat of their brow. That knowledge is sadly, irretrievably, gone but waiting to be rediscovered. This may be the only place on the planet that this could happen....please keep discussing it....with an open, curious mind

Thank you for this @SteamCoffee.

jumper

PMJ said:

jumper said:

Fizz said:

I believe that trapped air has been blamed for condensate not descending. Water vapor lock doesn't make sense to me.

None of these things make any sense.......
there is no significant change in any of the relationships inside the system. There is no trapping or holding up of anything. Gravity is still gravity and condensate runs as normal.

If air is not let in when the burner goes off the system just continues doing what it was doing...delivering steam to the rads. The amount delivered tapers down to a stop and the system then sits in a place much easier to restart without all that air to remove.

What one pipe needs is a method for separating condensate draining from steam entry. Then you can balance with two pipe type TRV. There are ways to to do that. For fun regard the JJ Wilson steam fitting patent on this website. Or consult LostArt about installing two pipe terminals on one pipe system.

PMJ

jumper said:

PMJ said:

jumper said:

Fizz said:

I believe that trapped air has been blamed for condensate not descending. Water vapor lock doesn't make sense to me.

None of these things make any sense.......
there is no significant change in any of the relationships inside the system. There is no trapping or holding up of anything. Gravity is still gravity and condensate runs as normal.

If air is not let in when the burner goes off the system just continues doing what it was doing...delivering steam to the rads. The amount delivered tapers down to a stop and the system then sits in a place much easier to restart without all that air to remove.

What one pipe needs is a method for separating condensate draining from steam entry. Then you can balance with two pipe type TRV. There are ways to to do that. For fun regard the JJ Wilson steam fitting patent on this website. Or consult LostArt about installing two pipe terminals on one pipe system.

The thing about TRV's is that they are trying to change what any given radiator is doing both suddenly and dramatically. That was never something I ever wished to do so I haven't thought about it much.

In my two pipe I make rooms ongoing warmer or cooler by effecting less fill in a particular rad with the inlet valve. But then that level of fill in that rad is ongoing cycle after cycle. Vacuum doesn't change anything about my ability maintain that and probably enhances it. I think standard one pipe with limiting vents would operate and be repeatable the same way. This is all I have thought about and is all that Hoffman is addressing.

The thing is that somewhere 90%+ of the filling of the system in natural vacuum each cycle occurs in sub-atmospheric conditions. A TRV outside of a check valve in a one pipe system will have no effect during this time. To me, balancing is not the right term for trying to start and stop steam flow altogether in certain rads. To me balancing implies an ongoing continuous flow with more going to certain areas than others.

Handling a lot of air surely will facilitate more sudden changes. For me air has become too much of an enemy now that I have experienced life without it. I would be trying to get the fill level everywhere I could repeat every cycle that would give me the temperature differences I wanted. Trying to go from on to full off in certain rads on a regular basis will be tough in natural vacuum. Much easier with the whole system full of air on every start up.

Anyway, for those without TRVs I see one pipe natural vacuum as very doable. I'll have to look again at the supply side devices @jumper has brought up.

ChrisJ

@PMJ
I mean, that's great and all except for the fact all supply valves are wide open on single pipe systems. There is no "turning them down". This is the flaw in what you're saying. We literally use the air to slow them down. You cannot do anything with the inlet valve.

Also, TRVs use a wax motor, they aren't sudden. They can slow radiators down just as you are only they're doing it in real time automatically. And they are available for two pipe systems as well.

There's much you do not understand about single pipe behavior my friend.

PMJ

> @ChrisJ said:
> @PMJ
> I mean, that's great and all except for the fact all supply valves are wide open on single pipe systems. There is no "turning them down". This is the flaw in what you're saying. We literally use the air to slow them down. You cannot do anything with the inlet valve.
>
> Also, TRVs use a wax motor, they aren't sudden. They can slow radiators down just as you are only they're doing it in real time automatically. And they are available for two pipe systems as well.
>
> There's much you do not understand about single pipe behavior my friend.
>

Gee @ChrisJ , if you read carefully I said that the limiting vent valves in one pipe achieve the same effect as inlet valves in two pipe. You read somehow that I said close the inlet valves on one pipe. I really do know that is not an option.

On the TRVs I will just ask you to state if you are interested to discuss the technical specifics or not. That is all I am interested in. I think due to the fact that it may be a long time between two points when the system would actually be open to the TRV the change from the system's perspective might be quite large.

Are you interested to pursue the technical aspects of this?

ChrisJ

> @PMJ said:
> > @ChrisJ said:
> > @PMJ
> > I mean, that's great and all except for the fact all supply valves are wide open on single pipe systems. There is no "turning them down". This is the flaw in what you're saying. We literally use the air to slow them down. You cannot do anything with the inlet valve.
> >
> > Also, TRVs use a wax motor, they aren't sudden. They can slow radiators down just as you are only they're doing it in real time automatically. And they are available for two pipe systems as well.
> >
> > There's much you do not understand about single pipe behavior my friend.
> >
>
> Gee @ChrisJ , if you read carefully I said that the limiting vent valves in one pipe achieve the same effect as inlet valves in two pipe. You read somehow that I said close the inlet valves on one pipe. I really do know that is not an option.
>
> On the TRVs I will just ask you to state if you are interested to discuss the technical specifics or not. That is all I am interested in. I think due to the fact that it may be a long time between two points when the system would actually be open to the TRV the change from the system's perspective might be quite large.
>
> Are you interested to pursue the technical aspects of this?
>


I do not know what you're asking about TRVs?

PMJ

That was a yes or no question. I will assume the answer is no unless I hear otherwise.

A few others above have clearly said yes.

ChrisJ

PMJ said:

That was a yes or no question. I will assume the answer is no unless I hear otherwise.



A few others above have clearly said yes.

No.
I'll change my answer when I see some actual evidence.

You have a two pipe steam system running below atmosphere. EVERYONE on here knows that's possible.

You talk about being able to hold radiators back by throttling with the supply valves on a two pipe system. Again, everyone on here knows that's possible.

You have not shown one person with a modern cycling single pipe steam system running successfully in a vacuum and being able to balance it. If someone wishes to experiment on their single pipe system to see what happens I'm all for it.

If @acwagner or @Gary Smith experiment and find it works, that would be absolutely fantastic and I'd love to hear about it. As long as they understand what they are getting in to. Completely uncharted territory with a huge chance of failure and disappointment.

PMJ

ChrisJ said:

PMJ said:

That was a yes or no question. I will assume the answer is no unless I hear otherwise.



A few others above have clearly said yes.

No.
I'll change my answer when I see some actual evidence.

Good enough. If Hoffman's Engineering Dept. didn't provide you enough evidence that one pipe vacuum steam is a real thing I am quite sure I can't. TRV's are a detail on top.

Maybe there should be a whole new category here for vacuum steam only so only those really interested can work along with each other and not upset anyone.

ChrisJ

PMJ said:

ChrisJ said:

PMJ said:

That was a yes or no question. I will assume the answer is no unless I hear otherwise.



A few others above have clearly said yes.

No.
I'll change my answer when I see some actual evidence.

Good enough. If Hoffman's Engineering Dept. didn't provide you enough evidence that one pipe vacuum steam is a real thing I am quite sure I can't. TRV's are a detail on top.

Maybe there should be a whole new category here for vacuum steam only so only those really interested can work along with each other and not upset anyone.

With all due respect @PMJ sales literature does not prove anything. They were selling stuff.

I will gladly work along with anyone experimenting on a single pipe system.

@acwagner and @Gary Smith have my full support and I will help them any way I can. @ethicalpaul and @KC_Jones as well of course.


I would also like to keep the discussion respectful and kind. Just because I don't agree with you doesn't mean I'm upset.

acwagner

I have a vacuum gauge on order. Once it arrives, I plan on bench testing my DIY radiator check valve to see if it reliably holds a vacuum.

@PMJ what level of vacuum do you typically see on your system? I recall somewhere you mentioned around 5-6 in HG. Is that right?

PMJ

acwagner said:

I have a vacuum gauge on order. Once it arrives, I plan on bench testing my DIY radiator check valve to see if it reliably holds a vacuum.

@PMJ what level of vacuum do you typically see on your system? I recall somewhere you mentioned around 5-6 in HG. Is that right?

That is correct at the peak each cycle.

I would expect one pipe systems to be significantly higher as I think most designs have a much higher percentage of the total piping occupied with steam.

Good luck with the valve. A breakthrough of sorts is needed here.