Converting a Church to Hydro HE from steam

ScottMP

We did this job a year ago but I never got around to posting the pictures.

The church used to be steam and we removed the steam, coverted the cast iron to hot water and added some baseboard. Two KBN's with a Wilo and zone valves.

Scott

Dave Yates (GrandPAH)

heavenly work!

Nice, very nice! Submit that for the RPA or GMC or both contests. Our experience has been 70% reduction in fuel consumption for this type of application. Are you tracking (or are they) those numbers?



Sounds far-fetched due to the on-paper stated efficiencies and the 15-point-spread, but it's the mod in modcon that continually readjusts to maintain proper load-match and peak eff while the on/off appliance real-world efficiencies stumble into the basement during the majority of the heating season.

Mark Eatherton

Glad to see you found religion ...:-)

And I am certain they are glad that they found YOU!



What happened to your ProPress? Did Chris take it over and not allowing anyone else the opportunity to save you labor?



Glad to see you using WILO and Lochinvar. What are your opinions on those two key products?



Keep up the excellent work.



ME

Steamhead

What condition

was the steam system in? Was this the usual poorly-maintained system?



And with little or no maintenance, how long do you think the new system will last?

Mike Kusiak_2

Real world efficiency?

I wonder how much real world efficiency is gained from a conversion like this? Keep in mind that a church is typically used only used a couple of days a week. The remaining days it is vacant, with a deep setback which may require no boiler operation at all.



A building which is in use 24/7 will definitely benefit from a high efficiency condensing system, where constant temperatures are maintained. I think the church would benefit more from a system which would have a high pickup factor, so it could be brought up to temperature quickly when needed. Steam seems to be the ideal system for this type of operation.



I am curious how long it will take the condensing system to come out of deep setback, and if it will actually be condensing while doing so?

ScottMP

The church is used quite a bit more

than you would expect. This is not your one room church and I would have thought that the many zones and size of the system would have been a clue. This church has office's and a nursery that is used five days a week.

A system of this size coming out of a deep set back will of course be in condensing mode as the rush of cooler water goes through the system.

The church has also gained better control over the building as it now is broken down in the zones so that different areas can be managed instead of one big uncontrollably zone. Not heating water to 212 will drop their fuel usage. With thermostat reset, outdoor reset, condensing mode, zoning and the Wilo pump the Church's fuel usage will drop.

The system will operate for a long time as maintenance will be provided by my company and the system will be kept in top condition.

Steamhead

Maybe

"The system will operate for a long time as maintenance will be provided by my company and the system will be kept in top condition" as long as the board doesn't decide they can "save money" by cutting maintenance. It happens all the time. School systems are just as bad. Maintenance is done grudgingly if at all.



Mark, I remember you deliberately didn't maintain a modcon in your house so you could see what would happen. Correct me if I'm wrong, but didn't its efficiency drop to something like 68% in a couple years' time?

Mark Eatherton

Almost correct....

Closer to 5 years run time. Regardless, it has to become S.O.P. that when you sell a modcon, that you notify the owner that the appliance MUST have regular maintenance or their warranty will be nul and void, and their efficiency will suffer greatly.



I'm pretty sure that steam boiler manufacturers also recommend annual maintenance...



Just because people don't do it doesn't make it right tho...



As it pertains to converting a steam system to a high efficiency hydronic heating system, I think it has to be economically justifiable, and the annual cost of maintenance (on BOTH systems) needs to be taken into consideration on the life cycle costs of the systems.



From a historical point of view, steam WAS king. But even the king lost his throne to higher efficiency over in the land where it was born (Europe). People like Frank, Terry, Gerry and others who have made a living out of fixing and rehabbing steam systems deserve credit for their efforts, but I think they will eventually have to face reality, and in my opinion that reality is that these systems will eventually become too expensive (read fuel costs) to continue operation.



I too love the mechanics and romantacism of a well designed, installed, maintained and operated steam system, but the fact is, that converting them to a high efficiency hydronic heating system will result in significant (30 to 60%) reduction in fuel consumption, and THAT in and of itself is hard to ignore.



But as has been stated before, the only correct answer is, "It depends!"



Each job MUST be evaluated based on existing condition, future conditions and all considerations affecting the change.



ME

Steamhead

Exactly

ALL boilers require maintenance. You have provided us with a real good look at what is to come when people don't do the maintenance we tell them to do.



Many times, when Gordon or I tell people their gas equipment needs to be at least checked periodically, they tell us whoever installed it told them it "needed no maintenance". The installers were probably referring to the annual servicing on an oil-fired system (at which time many oil companies do almost nothing anyway) but the bottom line is the customers were told this, they believe it, and, many times, don't want to spend the money. Never mind that some of these showed alarmingly high CO levels........



Residential steam boiler makers have moved from float-type to probe-type low-water cutoffs for just this reason. People were not blowing down their float-type units and their boilers dry-fired and cracked as a result.



Regarding your numbers- "converting them to a high efficiency hydronic heating system will result in significant (30 to 60%) reduction in fuel consumption", what exactly are you comparing? What condition are the respective systems in? Are you citing the same things I've seen where a steam system in very poor condition is being compared to a brand-new hot-water system?



If so, we've gotten similar numbers by rehabbing the steam systems (and we have before-and-after numbers to back us up), at far less cost and disruption to the buildings. That is definitely in the customer's best interest.



Oh, and 90%+ boiler efficiency IS possible on steam. It's been done (by Hoval, Gasmaster and others), but not in America. Unfortunately, American boiler makers are really dragging their feet on this. The first one to come out with a higher-efficiency residential steamer is going to clean up big-time. The installed base of steam is just too big to ignore.

Dave Yates (GrandPAH)

passion fruit

Maybe the attached pic will help a wee bit. As ME, and others, have noted - it depends. This chart, I believe, clearly illustrates why we see such dramatic fuel savings with modcon appliances. Far more than the 15-point-spread listed as the rated efficiencies.



We've convered dozens of old 1- and 2-pipe steam systems over the decades - when it was the right approach. Our own office/apartment building, which was a 1903 vapor-vacuum system was converted almost 20-years ago. As has been the case with other conversions, the old piping and radiators did not leak.



We did have one - just one - that was a problem child. The cast iron baseboard had hairline cracks at many of the oval openings that weeped and the owner elected to have it all replaced. There was, as it turned out, a DIY repair concealed behind a basement wall too that had leaked steam for years - led to timber rot - but had gone undetected prior to the conversion. The steam system itself, however, had been altered by previous owners, and a few lousy 'mechanics' that it was a toss-up between completely renovating the steam system or changing to hot water. The new HO made the choice prior to our arrival and dictated how we were to bid the work.



As for our 1-pipe church conversion, that was a complex-wide make-over. They wanted a four-pipe chiller/heating system and we were the last bidder invited to play. I chose to play by my own rules, ignoring the specs, which I felt were using yesterday's technology while ignoring today's vast opportunities to conserve energy. Wipe the slate clean and start over!



As you'd expect, that required a connected load survey and a detailed heat loss/gain be calculated. Investigating the nooks and crannies revealed energy upgrades and the heat loss/gain revealed the 1-pipe rads were a virtual match for outdoor reset based hydronics. The more than a hundred year old tiled floors did not need to be disturbed because we utilized the twin-pipe valves and soldered extensions onto the inner-tube to accomodate the loooonnnnngggg rads. The stadium-like floor-pitch simply aided air-removal from each rad and reverse-return piping ensured even distribution. Constant temps are required, as is often the case with churches, to keep the organ from getting out of tune. A new steam boiler was incorporated to serve the rear seldom-used sanctuary.



Prior to our involvement, the church secretary would turn on the lone heat source - the old steam boiler - that was sized to heat the entire complex in order to be comfortable! She now has much better comfort by way of her inverter driven mini-split heat pump. For that matter, so does the entire complex. From 2,800-BTUs of cooling to more than 50-tons & all of it inverter driven modulating comfort that's miserly with fuel while being generous with comfort.



In fact, most of the church complex (except for the rear sanctuary where the invertes are A/C-only) can utilize the inverter heat pumps as either the primary or secondary heat source.



So, in the end it became a hybrid system that grants them the best opportunities to slash fuel costs while ensuring more than adequate comfort. At first, they weren't very interested in having a maintenance contract. Then the new steam boiler cracked from end-to-end because their maint guy failed to maintain the LWC's. Second new steam boiler was installed and maint contract signed. So, it seems obvious (to me) that you can wag the maintenance finger at both old and new technologies.



Just last week, we were adding Danfoss temp-regulating valves onto antique "OurOwn" vertical tube (come to a point under the cast iron cover) steam radiators in a victorian home.



We're not just steam, nor are we just hot water and we are - like many here - open to all forms of PHVAC and constantly striving to provide our customers with the best advice possible.

Mark Eatherton

It was a functional system...

2 pipe steam.



We only re-used the radiators.



I've done many conventional hydronic high efficiency retrofits, and seen the minimum 30% reduction. One HAS to believe that if we can save 30% 0n a hydronic to hydronic retrofit, then going from steam to hydronic has to hold even more potential.



Tracking it should be fairly simple. Therms per degree day per square foot for a home of comparable construction, minus DHW production costs, obviously.



I don't doubt you can decrease fuel consumption in a poorly operated/maintained steam system by 30%, but those are the ones that see a 60% reduction when going from steam to hydronic. And cost justification in your case probably makes more sense than a conversion.



I still think someone (Burnham) should commission you and Gordon to take the MegaSteam boiler and convert it to a natural gas modulating controls and see what happens. I am CERTAIN you could come up with some excellent candidates, and the technology is off shelf.



Maybe it's the FUEL companies that are holding the technology back :-) (Conspiracy theory)



ME

The Steam Whisperer (Formerly Boilerpro)

The chart.....

shows efficiency gains by both the mod and the con.  What many now believe is that most of the gain in eff from mod/cons is from the mod.  I've converted some steam boilers from on'/off operation to modulating and seen large  reductions in fuel usage without any other system changes.  Modulating steam boilers can be had in virtually all sizes now, and with more appropriate sizing of the steam boiler to the actual building load, the differences in efficiency start getting alot smaller. 

I've done tons of churchs and have seen nearly the same reductions in fuel usage when going from hot water to hot water without any changes in zoning.  I've seen 70% reductions, with most about 40% just by adding good controls and step fired non-condensing boilers. 

How much did the improved zoning save?

How much did the load matched equipment save?

To me, there are simply too many changes made during this conversion to single out the change from hot water to steam as being the chief source of the savings.

Here's a modulating steamer I just put in a church (converted commercial structure).  Its a Slantfin with a modulating  Powerflame burner with a max input of 400,000 and a Heattimer modulating control.

Boilerpro

Mark Eatherton

How low can you go....

BP, what is the smallest burner config you can come up with, and what is the turn down ratio of said burner?



Tell us more please.



How is the turn down controlled, via pressure or sensed temperature?



Thanks!





ME

gerry gill

Fascinating...Boilerpro

does that heatimer control allow moduation in the ounces pressure range or just pounds?

The Steam Whisperer (Formerly Boilerpro)

Mod Burner

This particular burner is the X4M model that is rated to provide full modulation from 400,000 down to 100,000 (4to1). I haven't checked the min input I have actually gotten, since the meter is hard to read at such low flows.   I have another one installed, the X4MHD(high turndown...11.4 to 1))  in a smaller Slantfin, that is rated from 400,000 down to 35,000.  So far I have only got that one down to 75,000, with the top at about 200,000, but I believe more can be gotten out of it.

Both are being operated at a single target pressure with a Heattimer Elite series modulating control.  The HD model is targeting 6 ounces in a one pipe system that will eventually get TRV's on all the rads with a master stat signaling the boiler to cycle.  The system heats the radiators completedly across at 0.7 ounce.   Heattimer does not have very sensitive pressure sensors, so for the 6 ounce target I used a CeComp pressure tranducer (Libertyville,IL?).  The owner is going for LEED certification on this renovation.



The 4 to 1 model is being used to provide steam to air handlers, targeting 2psi. I also specified as an optional control the Siemens RWF40, which could be configured to provide outdoor reset of pressure so the steam input to the air handlers could be modulated(this would be great for orifice vapor systems with TRV's)   Budgets were tight, so this didn't go for now.  Maybe later I will have the opportunitty to pull the Heattimer and upgrade to the RWF.



I do hope to put in a simple moduating thermostat controlled set up in a future project.  That would be much less expensive and work well for homes without breaking the budget.  I've explored this already, but need to do more research.  Honeywell used to make modulating thermostats, and still do I believe, but I am looking for a company with a better reputation for reliability. 

I plan to write a couple of more articles on the concepts behind these installs.  The first, Dan just put up in the Hot Tech Topics section.



Here's the HTD install.  The CEcomp pressure transducer is up to the left.

The larger Slantfin replaced a 1,200,000 input Weil that was leaking and the smaller replaced a 500,000 input Weil that had failed in the early 70's and the system abondoned, until now.



Boilerpro

The Steam Whisperer (Formerly Boilerpro)

If you use the right Transducer.....

It becomes a case of "how low can you go".  Heattimers transducers are not sensitive enough for most steam space heating systems, so I used one from CEcomp with the Heat timer.  More info is in my reply to ME.



Boilerpro

Mark Eatherton

Fascinating indeed...

Thanks for the response BP.



I am certain that you have run these through a combustion analyzer, and with that wide of a range, you could chew up some serious printer paper charting burner /boiler performance, but if you could share some numbers from the top and bottom of the burner's capacity, it sure would help further the cause. Especially the smaller one.



Hey Frank, looks like someone out there has been listening and reading!



Is Noel Murdough still with SlantFin or did he move on? This sounds like something HE would have hatched.



Thanks again BP.



ME (From a hotel room somewhere in NJ...)

Dave Yates (GrandPAH)

has me wondering too

We've derated steam (and hot water) CI boilers in the past that were sized by the doorway or curb method and in each case we've let the mfgr's engineers dictate how low we can go. Sustained flue gas condensation was the concern. Never took one (CI, that is) that low. So, my question has to be - did the mfgr approve the mod and its range for what's traditionally been a non-mod app?



Danged interesting and informative and will we never stop learning new tricks(G)?

The Steam Whisperer (Formerly Boilerpro)

Numbers, et el

From low (75,000) to high (200,000) fire and approximate input signals.

1%:  81.7 % eff with 74% EA, 6.4 CO2

30%: 81.6 eff with 55% EA, 7.3 CO2

60%: 82.1 Eff with 21.7% EA, 9.3 CO2

90%: 81.2 Eff with 28.7 EA, 8.9 CO2

100%: 80.1Eff with 35.8 EA, 8.4 CO2



These were taken with chamber liner installed, without the liner I have seen about a 2 % gain.    Flame impingement does not appear to be a problem without a chamber because the chamber is so large.  I believe I can get a lower "low fire" with improved draft control and maybe improve the numbers overall.  On the larger input model, I have much better draft control, no chmaber liner, and was able to keep the excess air consistantly at about 30 to 35%.  This was higher than I liked but the flame began to rumble too much at one point in its range so the air had to be increased across the whole range. 

The burners are hard to tune because the motor drives the air damper directly.

Noel has moved on from Slant Fin.

This combination came into being after seeing about a 40% reduction in fuel costs on a system I worked on after we did some simple upgrades to the system, tuned the boiler and added modulating control to the burner.  Lots of digging yielded the PowerFlame burner and the Slantfin, with its cavernous chamber and wetback design looked like a solid boiler to work with.  I have looked everywhere and could not find any other manufacturer making burners with this low of input range.  I have several Slantfins with Heatwise burners in them and am seeing about 82% efficiencies at full rating.  The Heatwise burners can go extremely low on excess air (10% and under if I remember correctly) and still run clean in these boilers with no chamber.

With the bigger  multi- pass boilers I've upgraded to modulation, the low end efficiencies came up more than with the typical single pass cast iron sectional design.  I suspect that when the CI boilers are on low fire, the back end sections really are not doing much heat transfer through the pinned surface, but the front sections are still fully loaded, so heat transfer efficiency doesn't go up much.  With multipass boiler, we are still using the complete heat transfer surface so efficiences go up with lower firing rates

I am still looking for a small multi-pass boiler to run these burners in.  I bet that would be the optimum set up for steam.   Any ideas????



Boilerpro

Steamhead

Just to give you all an idea

of the savings potential in Boilerpro's magnum opus, we have a customer with a very large Broomell system which has a large W-M LGB atmospheric gas boiler. All LGBs come standard with a lo-hi-lo gas train and most installers ignore this feature, as was the case here.



Gordon and I hooked the lo-hi-lo up, using a Vaporstat to drop to low fire at about 3 ounces. We had upgraded the venting the previous year so the lo-hi-lo was the only modification we made at that time.



The customer reported a 40% reduction in his gas consumption, relative to the previous season on a therms-per-degree-day basis- for the price of some wire, a relay, a Vaporstat, some pipe fittings and some know-how.



Don't forget, this was an atmospheric where the combustion air quantity is not reduced on low fire, which limits turndown as the gas/air mix gets too lean for good combustion. Boilerpro is using a power burner which I'm sure controls both, and uses full-mod to boot- just like the old coal boilers did.



I'm watching and waiting.



And Noel is now at Laars.

Jamie Hall

Sob

You guys make me weep with your lovely turn downs.  Now can someone please do it with oil?



I was wondering where Noel had gotten to -- haven't seen him on the Wall in a while.

The Steam Whisperer (Formerly Boilerpro)

For Oil.....

Take a look at Weishaupt.  They have at least high/low on thier oil burners.



Boilerpro

The Steam Whisperer (Formerly Boilerpro)

One nice thing....

about the low fire on the LGB is that the excess air doesn't really seem to go that high, so your firing efficiency only drops 3 or 4 points from high fire.   This is really handy, since I have never met a LGB that wasn't grossly oversized.  I just pull the wire off the high fire gas valve, and all is good.  I don't remember if those Broomells have inlet orifices, but if they do, you may want to try a 2 stage thermostat to control that burner.   



Boilerpro 

gerry gill

BP- what was the name of the article

Dan put in hot topics? there is a slew of things in there with no search feature.

Steamhead

I don't think they did

the quintuple valve was sized to the radiator it was meant to serve, but I don't think they used the 80% rule since the water seal kept steam from reaching the return. 

The Steam Whisperer (Formerly Boilerpro)

Quintuple valve....

I looked them up and it looks like it used orifices to meter steam flow in the valve, so it should be a perfect candidate for a two stage thermostat or a full mod burner.

Boilerpro

The Steam Whisperer (Formerly Boilerpro)

It is...

"Taking Another Look at Steam Boiler Sizing Methods".  It is the first of a series I have in mind,  This one addresses one pipe steam boilers, the next will talk about two pipe steam boilers.  Then onto heating plant design with these concepts in mind.   Hopefully they will generate alot of discussion and create more light, not just heat!



Boilerpro

steve_38

Nice Job !

Where is the Oil Tank or Tanks located ?  Usually 80% of the time an oil burner brakes down is because of fuel related problems...  did you install a new tank? where did you locate it buried, above, or basement ?