PLC steam boiler control

tim smith

Anyone had any luck setting up a PLC control with od & id temp inputs adjusting run times. I know Heat timer makes them but they seem to be a bit overkill for these smaller apt bldg jobs. Tekmar of course has one but a little more limited and does not last very well from what we found. Just thought could be a good build up control with tweaking capabilities. Just a thought, may be far fetched although?
Tim

mattmia2

Someone on here did it, don't remember who. I think it was more a homeowner project.

tim smith

Matt, it is an interesting option I think, multiple inputs to adjust timed outputs are what I feel is really needed.

mattmia2

They did something with sensing temp at the end of the main, not sure if they were using outdoor temp or not. The posts should be here if you can successfully search for them. I think someone was trying to market a system for residential boilers, might have been the same person.

Jamie Hall

Contact @PMJ . He's done a fair amount of experimentation with that sort of thing.

ChrisJ

mattmia2 said:

They did something with sensing temp at the end of the main, not sure if they were using outdoor temp or not. The posts should be here if you can successfully search for them. I think someone was trying to market a system for residential boilers, might have been the same person.

MarkS and the Ecosteam?

KC_Jones

It's called ecosteam and it's no longer made. Once Mark brought it to market all the people that were interested in it and said they'd buy it, disappeared. I was a beta tester for mine, gave him some feedback and tweaked it a bit until it was working as expected with appropriate controls and I am really glad I did that.

It was a fraction of the cost of Heatimer and Tekmar, very simple to install and program due to having very nice instructions. It took my well running decent system to another level.

It maintains the temperature dead on, no swings, no dead band, just perfectly even heat all the time.

I can't sing enough praises for the system. The only problem I see is some day it's probably going to die and I will be back to crap, hopefully I sell the house before that.

PMJ

@tim smith ,

As stated above, Ecosteam was a really good PLC solution as confirmed by those few who still have it. It is still unclear to me why this market didn't take to it.

Your idea is hardly far fetched - at least from the technical side. I have run the same PLC that is in the Ecosteam, tweaking my own programs, for many years now. There isn't a better or simpler platform from which to be able to tweak things. At this point, frankly, I can't picture running a residential steam system without the sensing/timing capabilities that a PLC brings to the table.

I'm guessing it is the potential legal liabilities faced when doing anything to systems on a custom control basis with anything other than commercially available components that stops contractors from tinkering, which is understandable. It is at the same time extremely unfortunate as I think contractors would actually be the best innovators.

Anyway, I'm happy to share what I do any time with anyone. The steam heat I enjoy today is far superior to what I originally had with standard controls.

mattmia2

PMJ said:

As stated above, Ecosteam was a really good PLC solution as confirmed by those few who still have it. It is still unclear to me why this market didn't take to it.

I think the market that can install it properly is very small. It is so hard to find someone who can even read the manual for a steam boiler much less someone that understands why going beyond that is beneficial, the demand is probably only a bit more than the dozen or so really good steam pros here. Not only does the contractor have to understand it but they also have to then convince the owner to pay extra for it up front (although I suspect it pays for itself in fuel savings if done properly).

@pmj do you sense outdoor temp and use outdoor reset on the length of the burn time or just temp of the mains and t-stat calls?

PMJ

@mattmia2,
No outdoor temperature sensing. I wanted to keep it real simple. Fundamentally, leaving vacuum out of it for now, I stop every new burn a set time after steam arrives at a sensor on the most remote radiator in my system which is in my garage. This gives me a set partial fill of the system no matter the condition of the system at the starting point. Then, if the call is still in progress, the next burn can't start till a set time after that same sensor opens again, signaling that a set amount(not all) of steam in the radiators has condensed and is now in the rooms. That's the extent of the control...real simple. I tweaked the two timers for a while, but haven't changed them in years. 90% of the code in the PLC is just there for data collection and visualization on the touch screen.

Anyone thinking about the above can see how the burn lengths and the wait times in between them will be changed by how fast the steam is condensing which is directly related to the temperature outside. The two timers just need to be such that on design day the total burn time/hour will cover the demand if the call goes on a really long time - that is - continuously cycling as frequently as these two timers will allow. On average days of course the tstat will be satisfied and the calls will be shorter. The burns always stop way before the system is full of steam though so there never is any pressure. The dead men installed lots of extra radiation so there is no reason to ever get anywhere near full of steam - even on design day. The burns have no choice but to be evenly spaced so the heat ends up a lot more even with far less overshoot.

Natural vacuum between cycles improves things even more, but I'll leave that out of the conversation for now. It isn't required for this approach to significantly improve things.

ethicalpaul

> It is still unclear to me why this market didn't take to it.

yeah, this market is so open to new and interesting ideas, how could this have happened!!?

ChrisJ

ethicalpaul said:

> It is still unclear to me why this market didn't take to it.

yeah, this market is so open to new and interesting ideas, how could this have happened!!?

T87's and Pressuretrols set to 2 PSIG, sizing boilers the way they did in the 1940s and on and on and on.

Instead of working on steam heat systems like it's 2023, we keep pretending it's 100 years ago.


/RANT

tim smith

I feel the od reset based on time is a simple elegant approach. Simple to me is better. I know there are many people on here with much more experience on steam and really appreciate the feed back. A buddy of mine who is an industrial steam guy and I are talking through this. He runs a public health district steam plant maintenance here and has a lot of experience with plcs. Hopefully between me being inquisitive, the great people here and my buddy we can come up with a logical solution.
Thanks again
Tim

Jamie Hall

ethicalpaul said:

> It is still unclear to me why this market didn't take to it.

yeah, this market is so open to new and interesting ideas, how could this have happened!!?

Simplicity, reliability, repairability, and cost.

ethicalpaul

> Simplicity, reliability, repairability, and cost.

Which of those are embraced by mod-con boilers? I understand I'm kind of arguing against myself here, but it is funny.

ChrisJ

Jamie Hall said:

ethicalpaul said:

> It is still unclear to me why this market didn't take to it.

yeah, this market is so open to new and interesting ideas, how could this have happened!!?

Simplicity, reliability, repairability, and cost.

The Ecosteam uses a PLC as well as other industrial components all of which can run for decades without any attention.

I respectfully disagree Jamie.

PMJ

ChrisJ said:

ethicalpaul said:

> It is still unclear to me why this market didn't take to it.

yeah, this market is so open to new and interesting ideas, how could this have happened!!?

T87's and Pressuretrols set to 2 PSIG, sizing boilers the way they did in the 1940s and on and on and on.

Seems to me the controls adopted during the switch to intermittent fire totally ignored the fact that the original design never planned to have radiators full and therefore never would have any pressure. Since the coal fired steam was constantly supplied it seems rather obvious that radiators could never be full or the occupants would have been roasted. Not knowing anything about steam I thought about what must have been there originally and I concluded early on that my boiler needed to supply the steam in pulses somehow to even things out. Something else besides tstat satisfaction or pressure needed to stop the burns before everything filled up. A boiler big enough to fill everything up turned out to be no issue at all...in fact I appreciate very much having the extra, as more off time between burns is then available for the vacuum to work its magic.

@tim smith , I lost interest in Od temp when I observed how it knew nothing of sun and wind which affects the demand a whole lot.

The rate of steam condensation is actually a measure of the demand in real time. It actually was the basis of damper control of the coal fire back in the day. The dead men used some actually not so simple devices to make use of it for control. They apparently weren't afraid of some amount of complexity in the pursuit of comfort. I'm actually doing something very similar with my simple control. The burns stay spaced out quite evenly and the %burn time per hour increases and decreases with the demand.

ChrisJ

@PMJ
You're still concerned about "the original design" from 100 years go as well.

"The dead men" didn't even have a thermostat most of the time and what they considered comfort most would consider unlivable now.

tim smith

I still wish they made a simple programmable thermostat that had maybe 6 on,offs that could accept an indoor sensor maybe for limit and an outdoor sensor for time offset. That would be a real simple solution for all these on off boilers in light commercial jobs. I know it sounds maybe bit too simplistic but many of them just run off time clock now and no thermostat which is good and bad.

ChrisJ

tim smith said:

I still wish they made a simple programmable thermostat that had maybe 6 on,offs that could accept an indoor sensor maybe for limit and an outdoor sensor for time offset. That would be a real simple solution for all these on off boilers in light commercial jobs. I know it sounds maybe bit too simplistic but many of them just run off time clock now and no thermostat which is good and bad.

What's "6 on,offs" ?

Dry contacts?

CLamb

mattmia2 said:

I think the market that can install it properly is very small. It is so hard to find someone who can even read the manual for a steam boiler much less someone that understands why going beyond that is beneficial, the demand is probably only a bit more than the dozen or so really good steam pros here. Not only does the contractor have to understand it but they also have to then convince the owner to pay extra for it up front (although I suspect it pays for itself in fuel savings if done properly).

With a properly designed user interface and proper instructions it should be easy to use and install. The problem with steam boiler manuals is not that installers can't read them but that installers won't read them.

@PMJ Perhaps you would put your designs on Github with an Open Source license?

Jamie Hall

ChrisJ said:

Jamie Hall said:

ethicalpaul said:

> It is still unclear to me why this market didn't take to it.

yeah, this market is so open to new and interesting ideas, how could this have happened!!?

Simplicity, reliability, repairability, and cost.

The Ecosteam uses a PLC as well as other industrial components all of which can run for decades without any attention.

I respectfully disagree Jamie.

I am probably biased by my work with cars and trucks, and airplanes. I truly do appreciate the elegance and refinement which current computer applications bring to both. No question. The application of computers -- dozens of them -- in such critters enables them to be more economical, easier to drive or fly, and so on.

Until the magic stops. Which it always will at some point. In an airplane, for example, if it is fly by wire -- all Airbus models and the Boeing 787 -- pretty much any idiot can fly it, if not all that well. But this is done with no fewer than three master computers and literally dozens of auxiliary ones, not to mention hundreds of sensors. When the magic stops for whatever reason -- and it does -- the folks in the front office are every bit as much passengers as the paying crowd in the back. Good luck. The planes I flew had varying degrees of magic, quite true -- but when all else failed (and it did now and then) you still had simple physical connections between your wheel or stick and pedals and the surfaces, and you still had a good deal of choice as to where you were going to end up. Similarly with cars, though less drastically. Many modern cars have literally no physical connection between the pedals on the floor and the wheel in your hands. So long as the magic works, wonderful. When it stops... with any kind of luck the runoff is a nice soft field. Of maybe it's just something non-critical that quits, like a body control module, and nothing works inside the car, but at least you can still stop it and steer it, even if you can't open the doors or windows.

Then pay someone with a multi-thousand piece of diagnostic equipment to find the problem. With luck, it's just a bad ground (out of several hundred). With less luck, fire the parts cannon for a four figure sum and hope.

I personally own two pickup trucks. The simple one I can tune and repair with a few dollars' worth of parts, a couple of wrenches and a screwdriver and a good ear. The other one -- and it's still older, but not as old -- nope, sorry. True, it doesn't need tuning that often. But, when it quits by the side of the road, it's dead until the tow truck shows up. A shade tree repair to get home isn't an option.

It's a real tradeoff between sophistication and elegance on one hand, and simplicity, reliability, repairability and cost on the other -- and different people have different preferences.

ChrisJ

Jamie Hall said:

ChrisJ said:

Jamie Hall said:

ethicalpaul said:

> It is still unclear to me why this market didn't take to it.

yeah, this market is so open to new and interesting ideas, how could this have happened!!?

Simplicity, reliability, repairability, and cost.

The Ecosteam uses a PLC as well as other industrial components all of which can run for decades without any attention.

I respectfully disagree Jamie.

I am probably biased by my work with cars and trucks, and airplanes. I truly do appreciate the elegance and refinement which current computer applications bring to both. No question. The application of computers -- dozens of them -- in such critters enables them to be more economical, easier to drive or fly, and so on.

Until the magic stops. Which it always will at some point. In an airplane, for example, if it is fly by wire -- all Airbus models and the Boeing 787 -- pretty much any idiot can fly it, if not all that well. But this is done with no fewer than three master computers and literally dozens of auxiliary ones, not to mention hundreds of sensors. When the magic stops for whatever reason -- and it does -- the folks in the front office are every bit as much passengers as the paying crowd in the back. Good luck. The planes I flew had varying degrees of magic, quite true -- but when all else failed (and it did now and then) you still had simple physical connections between your wheel or stick and pedals and the surfaces, and you still had a good deal of choice as to where you were going to end up. Similarly with cars, though less drastically. Many modern cars have literally no physical connection between the pedals on the floor and the wheel in your hands. So long as the magic works, wonderful. When it stops... with any kind of luck the runoff is a nice soft field. Of maybe it's just something non-critical that quits, like a body control module, and nothing works inside the car, but at least you can still stop it and steer it, even if you can't open the doors or windows.

Then pay someone with a multi-thousand piece of diagnostic equipment to find the problem. With luck, it's just a bad ground (out of several hundred). With less luck, fire the parts cannon for a four figure sum and hope.

I personally own two pickup trucks. The simple one I can tune and repair with a few dollars' worth of parts, a couple of wrenches and a screwdriver and a good ear. The other one -- and it's still older, but not as old -- nope, sorry. True, it doesn't need tuning that often. But, when it quits by the side of the road, it's dead until the tow truck shows up. A shade tree repair to get home isn't an option.

It's a real tradeoff between sophistication and elegance on one hand, and simplicity, reliability, repairability and cost on the other -- and different people have different preferences.

You're literally defending an extremely unreliable ignition system because it's cheaper to fix even though you fix it often.

Most people don't even know what a spark plug is now because they never deal with them. You're surrounded by literally millions of cars that do not have their ignition systems touched aside from spark plug replacement for decades and rarely have a problem. There's literally no such thing as a "tuneup" now. You replace the plugs every 100K miles or so, some want every 60K. But that's it. Coil on plug systems controlled by a computer, how lucky we are.

No spark plug wires, no distributor with vacuum advance, centrifugal advance, no points, no condenser to fail, it's all gone.

On a rare occasion a crankshaft position sensor or a coil fails but I assure you it's not every 10,000 miles like your points.


There's many other things as well but I'm just sticking with the ignition system comparison for this discussion.

ethicalpaul

It doesn't seem a valid comparison of a steam boiler controller PLC to a jumbo jet...

Jamie Hall

Um... yeah, valid points, @ChrisJ and @ethicalpaul . But -- I'll bet I'm (or someone is) still driving my stone age '70 C10 long after a computerized flashmobile has been compacted...

But I will certainly agree that the average citizen has no clue at all as to what makes their car or appliance -- or heating system -- work. Not absolutely sure, however, that being helpless in the face of a technological marvel is such a good thing.

mattmia2

There were far more complicated, expensive, and difficult to diagnose problems with the mechanical controls on my parents' 78 cutlass than a modern car

Jamie Hall

Your '78 Cutlass was well into the malaise era, as it is called. There were about a dozen years in there, give or take, where the technology was catching up to the regulations and mandates. I don't like to work on those catastrophes! I am perfectly content to grant -- happily -- that given the combination of panic over fuel shortages and panic over air pollution, with the resulting regulations, computer controls were -- and remain -- absolutely necessary for any reasonable car. It's almost (not quite) impossible to get the tight control required without the computers and the associated sensors, and I'm not opposed at all. Just saying that so long as the magic works, they're wonderful. The same thing is true in heating and air conditioning -- and honestly I would hope that advances which can still be made will be, although with the mandate to phase out all fuel burning devices I doubt that anyone would be willing to invest the money beyond where we are.

ChrisJ

I'd take the HEI ignition system on the 78 Olds over a 1970 for both performance and reliability.

Jamie Hall

I put a capacitive discharge HEI on my '66 Buick Skylark GS. Gained about 10 hp on the dynamometer since it got rid of the timing jitter from the points floating at high rpm. Nice unit. Didn't do a thing for peak torque, but I left it on anyway. Oddly, that was a permitted mod. for super stock.

I expect her part throttle economy would have been better with fuel injection -- and I'm sure her idle would have been (with that high overlap cam, there was no way that you could get a smooth idle without some surging!). However... there is no way to duplicate the rush when the mechanical secondaries on that big Carter opened up! New muscle cars are faster, I'll grant, and a lot easier to drive (and safer!)(brakes? whazzat? In spite of 13 inch aluminum fin drums, one stop from a full out run and you'd better let things cool -- or plan on dragging your foot!)(no power steering, no power brakes, no traction control...). Really a whole different mind set.

I still miss her, and I wonder where she it -- last I heard of her she had been fully restored, frame off, and was on the southern California show circuit. Serial 446676H271575.

PMJ

ChrisJ said:

@PMJ
You're still concerned about "the original design" from 100 years go as well.

"The dead men" didn't even have a thermostat most of the time and what they considered comfort most would consider unlivable now.

You are correct. I am concerned with the intentions of the designers of my 100 year old piping system for the simple reason that I am today running steam through that very same(their) piping system. I will say, however, that interested would be a more appropriate term.

I promise to remain interested in the achievements of all the hard workers that came before us, who accomplished so much with far fewer tools than we have, even if others aren't.