Report on steam to mod/con fuel savings

A.J.

We lost thee radiators all do to human error and we changed out about forty radiator valves do to leaks when we filled the system. All in all I felt O.K. about filling this old system with water because it was holding a vacuum.
As to weather or not this system needed a vacuum pump for certain I can't say for sure, you would probably know, the only thing I know is that it was installed circa 1964 when the first gas boiler was put in. That is part of it to, I know enough to get by on the steam system that are left out there thanks to my grandfather but there aren't a whole lot of them out there any more . Most of the techs. out there do not want to bother with them because they don't understand them at all. I say that because in the last year two more steam systems were put into early grave in my area, one were new owners wanted to get rid of the radiators in leu of baseboard and the other was a inn that is right know being completely remodeled with an upgrade to scorched air. It is a real shame because I thought they were a very elegant way to heat if everything is working properly.
It was a gamble but hopefully they will see a 50 to 60% in their fuel useage.

tim smith

Report on steam to mod/con fuel savings

Now I know I may be chastised a bit but the old steam system was very poor and not very large. Also customer wanted to add couple rads in basement and relocate boiler. Soooo that is why I changed it, OK. He just called me after it was in for a year, oil to gas, steam to water and replaced piping w/ added couple rads. New prestige 110 solo. 05/06 winter heating bill $2100.00 oil. 06/07 winter bill, $750.00 lets say he was very pleased. Just fyi, not to say it is always worth converting at all but this one was a simple repipe as it was not a large house and boiler centrally located. Great job, Tim

John Starcher_4

Isn't it great....

...when you hear news like that!

Good job, Tim!!!

Starch

Ken_40

Do you have parallel data?

By parallel data, I mean the following:

1. If the old boiler was running at 55% AFUE and a new steamer with 82% were selected, what would the "improvement savings" resulted in fuel alone?

2. Had the client put the cost of switching into a 6% CD, what did he lose - had he not put the money into a new system?

3. We cannot include the added work and comfort to the calculations, because either way, that would impact either staying with steam - and you adding a few risers & emitters with water - or, steam would be "other factors" likely to cancel each other out.

4. What was done with the riser holes in the oak floors?

5. How was the 'A'-word insulation on the old steam pipes dispoosed of and at what added cost.

6. What was the inherent disparity of oil vs. gas savings alone worth per year at current prices?

Final comments using what may NOT be the case in your area - but all valid considerations nonetheless: Simply going from an old beast of a steamer to an 82+% steamer saves a bunch annually. Switching from oil to gas around here would further result in a 30% fuel cost drop. Properly venting, insulating pipes and sizing the new steamer would improve economy and comfort by a ton.

The actual savings you state are real, regardless of by what means derived. But at what cost and means is the bigger question...

The rhetorical answer is why we generally cannot justify going from steam to water, despite the obvious reason to do so, e.g., condensing is an option with water, not with steam and THAT 15% added efficiency frequently is the primary justification to convert; and rightly so IMO.

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tim smith

response to Ken

Ken, here is the way I see it. 05 06 oil rates were averaging probably almost twice of Gas. Old boiler had to be replaced and he really wanted it moved. Asbestos had to be done anyway. Relocation and new boiler were a tough sell as with a new steam boiler and controls would have been within 4000.00 of this total job and the adding of rads would have complicated the job to such a point that I had figured there would be little difference in the net effect. My guess is that if we had gone w/ new gas steam boiler if feasible that the savings would have been similar. I just stated the switch from steam to water because it made the most sense not that the steam to water made up all the cost savings. Tim

Unknown

9 times out of 10

It's the system running condition and DD's... Then about 10% from the equipment. But people don't like that because it's not a good selling point, but it's true.

Ken_40

I'm sure you...

did the right thing, given all the exceptions you encountered - rather than why we generally find Steam to water conversions economically unjustifiable. I simply wanted to also state the typical reasons we usually cannot justify doing what you had to do, given the boiler move request, added radiation and other factors involved.

I was at that point with a few customers and believe it or not, the idea of the owner plugging holes in old oak floors scrubbed the conversions for us not once but a few times. Amazing what drives customer decision making process.

I'm sure you laid all the options out for the HO. All good contractors would.

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[Deleted User]

I'd have to dispute your 10%...

But I don't have time:-)

30 to 60 percent WEATHER COMPENSATED fuel savings is NOT an accident.

Let me guess, you refuse to sell new condensing technology....especially on hot water baseboard installations.

Hop on or get bypassed.

ME

Unknown

Hence system eff.

It's the system more than the boiler. Read the post.

Mike T., Swampeast MO

I can assure you the savings from a properly installed mod-con will be much more than 10% in nearly every condition.

A mod-con will is also a GREAT aid if you're really trying to save energy by lowering the general heat level. Conventional boilers get less efficient when you do this as they become more and more oversized with greater and greater cycle losses. Mod-cons get more efficient as not only do they modulate down, but the lower supply temperatures mean greater combustion efficiency.

Steamhead (in transit)

I agree with Ken

this quote from the original post says it all:

"the old steam system was very poor"

That is why we cannot take this as a comparison of the relative efficiencies of steam vs. hot-water. If you wanted to make such a comparison, both systems would have to be in optimum condition. This steam system was anything but.

Kind of reminds me of the "study" of 10 or so schools where the steam systems were in such poor condition they were cycling the boilers manually, among other things. Then they tore everything out and put in new hot-water systems, and called it a comparison of hot-water vs. steam..........

WRONG!!!!!

The head-to-head comparison still doesn't exist.

"Steamhead"

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Unknown

Hence system eff.

It's the system that needs repaired, but as you will see as this thread goes along this is a salesman's website.

Home Depot Employee_2

just to add

I always referred to that mind set as the salesman versus repairman principal.
The salesman wants to replace with the latest and greatist. The repairman wants to fix it and more often than not sides with the end user and feels equipment should last and be used for 40+ years.

However, all parties tend to be similar in their thought patterns when it comes to buying, keeping and replacing automobiles.
Ask yourself, is it prestige or ROI? No for most reliability!

ALH_4

Mod/Cons and Salesmen

It is true that the difference in ability to extract heat from combustion in mod/cons versus traditional boilers at steady state is approximately equal to the latent heat content of the flue gasses.

However, I think a good deal of the savings from mod/cons are not due to the "con", but because of the "mod". Once you have a modulating boiler with the ability to condense, controlled by outdoor reset, you can no longer separate the boiler from the system when talking about efficiency. The integration of the boiler into the system is a major advancement, and that in general is the reason why mod/cons tend to save more than 10%. Analog beats digital, hands down...at least when it comes to heating.

Therefore, I do not think that selling a mod/con into a system not originally designed for one is selling unnecessary equipment.

Converting steam to hot water is a different story. Steam systems are inherently somewhat analog, particularly with TRV's, however you cannot easily modulate or condense a steam boiler to match the heating load. Therefore, I think there are some savings to be had by conversion to a mod/con. However, the payback is *generally* not sufficient to justify the cost. The owner of the system discussed in this thread may have realized 75% (WAG) of those savings with a perfectly functioning steam system. In this case, the economics appear to have tipped in favor of the hot water conversion. If the steam radiators had leaked, I have a feeling it may have been different.

Then other factors, such as domestic hot water production, come into play. It's more complicated than 10%.

ttekushan_3

when a heating sys is so far off the mark

drastic changes have to be made. In this case, boiler relocation, boiler efficiency in the dumper, perhaps inadequate radiation (which is a great energy waster in non-modulating oversize-boiler'd steam systems) and overall disrepair. Considering the range of choices available under these circumstances, this one seems fine. It certainly got incredibly great results.

But some general "flip sides" not in reference to Tim's work:

Flip side #1, Met a homeowner who converted to a Prestige 11O+indirect DHW from steam for the purposes of boiler relocation (crusty 1970 Bryant atmospheric gas boiler and typical hot water heater replaced). He claims his weather compensated total gas usage savings are about 25% and is disappointed due to the cost of the job. I'm waiting for details.

Flip side #2, Met an architect who had his existing steam CI boiler relocated and piping redone; conversion from steam to HW done to recover basement space for a recreation room. Also some rearrangement of radiation at the same time. This was done 20 years ago. Weather compensated fuel usage INCREASED about 30% over the steam system. He stands by this claim since the outcome's been consistent over time and was so shocking, frankly. And he says thats erring on the side of conservatism. Obviously the boiler size is now inappropriate, but just goes to show how important these kind of things are.

Flip side #3, Church school/church offices building where firing % time is easily determined by the ProTemp ODR control, firing rate determined by direct observation of the two-stage steam boiler:

With 27% INCREASE of edr (reattached radiation formerly removed due to poor system operation), boiler repair/descale/partial tube replacement/clean&adjust, pneumatic control system serviced, and a couple of vent replacements (no traps rebuilt or replaced, shame on me);

The percentage run time via the ProTemp control had to be reduced by 35% at all outdoor temps and furthermore, the boiler has begun to run at 60% power HALF the total cycle time (couldn't attain pressure to downfire prior to servicing). Even heat throughout. No overheating of any spaces. All while totally eliminating the electric and gas used by the auxiliary heaters installed throughout the facility to compensate for the steam system failures over time. I worked at this facility for 3.5 full days to achieve these results.

Suppose the church converted the heating system as was suggested by every single heating company that came out to throw their hands up at the existing system. More than one showed up not with a service truck, but a clipboard for a system replacement quote. Suppose they got the kind of results seen here at the end of a (costly) conversion process.

I'll leave it to the reader to figure out what everyone's conclusion would be about steam systems. I'll leave it to the reader to imagine what "news" about system conversion gets posted on sites like this. I'll leave it to the reader to determine if the organizations with a vested interest in new equipment sales would observe these postings and what "facts" would be disseminated throughout the heating contracting industry. I'll leave it to the reader to determine if steam technology is taught at any level due to these "facts." I'll leave it to the reader to predict the performance of a steam heating system when put in the care of someone who has not been taught anything accurate about the theory and practice of steam heating.

And I'll leave it to the reader to look up "self fulfilling prophecy."

-Terry

ttekushan_3

When I worked with

a laid off pipe fitter, he told me of the the last job he had worked on for Cleveland schools that involved not only replacing all the steam traps but the boilers were torn down and rebuilt, and boiler controls were updated. According to his boss, the buildings affected by the program were seeing a 44% reduction in fuel usage on average.

No other changes to the buildings were made.

-Terry

ttekushan_3

Andrew

I hate to disagree on the Modulation of steam. Pressure is an outstanding indicator of the steam load, since we are heating with latent heat and not temp differentials. And it supports your MOD vs CON theory with which I wholeheartedly agree. MOD has the potential to give the biggest bang for the buck.

I worked on a steam system with a mid 1970's vintage Bryan forced draft boiler. The high firing rated is set by boiler size, etc. The low firing rate is set with a rheostat on the front panel for the burner control box. It takes a little time with a system to determine just the right pressuretrol setting to hand off to the low fire level. Then more time to literally dial in the the low firing rate. Once you got it, its great!

Oh, yeah. My point is that there's also a "manual/automatic" switch on that burner control. In the manual position, the rheostat is the only thing controlling the firing rate. And its continuously variable. I installed a better pressure gage to get ounces of resolution. So here's a system with room thermostats and long piping runs, etc. Yet if I kept my hand on that control and set, say 12oz of pressure, and used the "human feedback loop" everything heated so beautifully, and the combustion numbers were quite good (about 82% gross eff on my UEI 125). Anything resembling high fire was only required at the beginning of a cold start cycle.

As my mind wandered, it wandered to non return vents and vacuum breakers. It wandered to a compound pressure gage and it wandered to a vaporstat at the tail end of the system to assure steam saturation. It wandered to an ever decreasing firing rate. Then it wandered to vacuum! Now, THAT would have been something to behold!

Who said I was a vaporhead? Vacuumhead would be better!

-Terry

ALH_4

Modulation

I'll buy that. In many ways, steam is a much more elegant way to heat than hot water. Why isn't there a modulating residential steam boiler on the market that operates as you describe?

Unknown

I had a similar experience

at Colby Sawyer College with a similar retrofit.

Noel

Uni R_3

And I'll agree with Steamhead

I achieved almost verbatim the same expense/savings numbers switching from an old oil fired burner with a modern Riello burner with ODR to a Prestige 110 last year, and both used the same monoflo-piped fin-tube emitters.

That's not a valid comparison of steam to hot water.

tim smith

I knew this would raise a little debate

Just for info, we are primarily a service company who does quite a bit of necessary replacement. NOT a mod/con sales company. If this system had any reasonable ressurrection possibilities we would have done this. We repair by far more systems, steam and water, than we replace. We love to fix things that are fixable. But, alas this was not near worth repair. Good luck out there, Tim

ttekushan_3

There IS. Oh wait-

its not 1929!

B-line Boilers via the Library

This one I worked on last year. Rebuilt the secondary air damper control (yes. atmospheric but with variable secondary air draft dampers, with complete closure on shutdown. The modulation controls are gone although the vaporstat is the next best choice. Check out the combustion numbers anyway. The dampers control excess air and helps control heat loss by closing when the gas shuts off. That's why I rebuilt the control. Its still quite useful. Gerry Gill said he came across a B-Line in Shaker Heights (Cleveland) functioning perfectly in its full glory.

-Terry

Note that this a two-base boiler. The combustion tests are for the right and left halves, the halves being dissimilar in size.

A.J.

R.O.I.

We are seeing about a 25% to 35% savings for our customers just by switching out there old atmospheric boilers gas boilers to MOD/CON boilers.
I sleep pretty well knowing that I can save somebody that much money year after year. Until the MOD/CON boilers were released here the only option I had was to replace those old boilers with basically the same thing, it just didn't fell right.
Our company just did a bigger steam to water conversion with MOD/CON boilers that I will post some info. on latter in the season after some numbers start to come in.
We had been working on this system for about six years and fixed or replaced a number of things including but not limited to traps,boiler cleaner ajusting the pressure switch, and a new vaccum pump. I just didn't think a new steam boiler was the right direction, we will see.

Leo G_101

Also

let's remember that these mod/cons need to be completely serviced every year. If they are used for pool/spa heating during the summer, then be ready for twice yearly cleaning.

Throw in the probable need to replace the boiler in 15 or less years.

The need to stock more then a thermocouple or gas valve.

and worst of all, the monkeys out there who are now the "mod/con experts" that I have to follow and break the bad news to the homeowners that their system is totaly piped wrong! and needs extensive re-work!! Thus doubling their instal cost!!!

I love the mod/cons, but when asked by a potential customer what would I install, I have to honestly state that I would still go with an atmospheric boiler with a good tekmar. I am still not convinced that when push comes to shove over the life of the equipment, that you save that much more money. You may use less gas, which is good, but if I have to put 3 of these boilers in over the life of a regular boiler, then I still think that your green footprint, using a modcon, is not that much smaller, nor is there that much moola saved.

An example is from 3 years ago. Slant-fin atmospheric, heating baseboard. Piped horribly, bouncing off its limit. We went in , cleaned up the piping, added a Honeywell AQ boiler control with ODR. In three heating seasons, the average yearly savings have been 18%. Not as good as 30-40%, but the initial install cost was minimal. Servicing costs are about 1/2 of a mod/con service. And the boiler is already 11 years old, and looks like it should last another thirty years. Comfort next to none. And I do have a thermocouple and gas valve readily available!

Leo G

Steamhead (in transit)

\"Cleaned up the Piping..\"

....is an understatement. Beautiful job!



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Unknown

CSI

Save a few thousand dollars a year in fuel seemed like a good idea at the time. But it was going to cost 75 large to do it.

Unknown

CSI

(Don't you understand Mister Contractor Man we could save a few thousand dollars a year in fuel.) I do understand believe me. I am giving away a $75 large bill job for a small repair job. What you don't understand is the ROI is about 50 years. (But that is not what anybody else said.) Yes I know.

Steamhead (in transit)

But you don't mention

what condition these older boilers were in, what efficiency they were running at, whether or not they were oversized and by how much, whether there were any system issues that you fixed when you replaced the boilers, etc, etc, etc.

For fuel-savings numbers to mean anything at all, we have to know these things. Otherwise we sound like the stereotypical used-car salesmen.

"Steamhead"

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Unknown

Steamhead

Average Condition for their age lotsa steel left. Cosmetically they looked like crap. Burner eff. 83% to 84%. I don't consider any steam boiler oversized if I can adjust the fire rate to obtain a good cycle per hour rate. The bigger the better. I want a large steam chest. The systems had the usual space temperature control issues, traps, condensate piping issues, leaks in general. And for you Steamhead you know as well as I that a good running steam system can, with ALL THINGS considered easily rival the numbers of a Con-Mod on seasonal efficiency's especially when they over-pump the Mod-Con. Of course all things must be considered. And yes I mean less than 10%.

A.J.

Hay Steamhead

I have never meet you but I would love to get your opinion on the situation this system was in since you know steam inside & out.Here is the short version.
Peerless natural gas boiler one million input,27 years old.
Connected radiation load 900,000 EDR @ 212 deg.
Heat loss shows 630,000 but load @ 70 deg design diff.
We have put in the last seven years since we have been ser
vicing it traps, both main & radiator, vacuum pump,boiler
treatment, and cranked the pressure down from three
pounds.
Now the boiler has been working better than it has been
in a long time according to the sisters since we have been.
Working on it but I was worried that their boiler was
going to go in the middle of winter just like their vacuum
pump did last winter.
With a $ 25,000 fuel bill last season and gas prices still
on the rise my thoughts are to save them on their costs.
I know a new steam boiler would do that but we are having
good success with the mod/con boilers just by sizing them
right and plugging them into the existing system.
That do you think ?

Steamhead (in transit)

You're skating on very thin ice

One of these days you're going to get a system that turns into a Swiss cheese and leaks all over the place. Then the lawyers will eat you and your business for lunch. I've seen systems where this has happened, one was in a beautiful old church that was severely damaged. We refused to work on it.

Another thing to consider is that if steam pipes run in outside walls, and you fill them with water, they may freeze and burst, again damaging the building.

We do not recommend or perform this type of conversion, and will not work on a system someone else has converted. Period. It's just not worth the risk, when we can get similar savings by fixing the steam.

Also, mod-cons seem to require a higher level of care and maintenance then the usual boilers. If the owners have a history of skimping on maintenance, they are certain to have trouble with those boilers later.

On that job I would have questioned why the vacuum pump was there. Knuckleheads have been known to add these where they were not needed, and they invariably screw up the traps. Then, if the Peerless was the typical inefficient atmospheric boiler, we would have replaced it with a wet-base power-burner unit. This would have eliminated the heat losses at the boiler base, and given them the option to switch fuels later without buying a new boiler.

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Steamhead (in transit)

You were very lucky

those were the only leaks you had. Better hope something else doesn't let go later on.

Not sure where you're operating, but every old American metropolitan area is filled with steam systems. These are either a great business opportunity (for us anyway) or a lot of trouble (for those who don't understand them). We have chosen the former position, and our customers love it.

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Unknown

Vacuum

Vacuum Pumps were used heavily in the 1940 till the 1960. Yes they have a purpose.

Steamhead (in transit)

Assuming

the system was originally designed to use a vac pump, you are correct. But if it was added later, it can cause major problems. Just ask Noel, he's pulled a bunch of them out.

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