Updating heating system

Glen_7

My home has a very old W/M atmospheric boiler (previously steam) that is now hot water and feeding six baseboard zones. I have a separate H/W heater for domestic water. Natural Gas is fuel source. I would like to replace the boiler and h/w heater this spring, and change two of the baseboard zones to radiant (kitchen and master bath) as those rooms will be gutted and have tile floors. I have read some on cast iron w/outdoor reset vs mod/con and am still not sure there is a clear choice. Also, I keep reading about open and closed systems. Since I'm eliminating the separate h/w heater and would probably have a separate storage tank, I'm not sure where this comes into play. I would like to know what to look for when I go out for proposals. I know there are different types of pex, as well as different metals in circulator pumps. Since my system is kind of a hybrid, any enlightenment would be appreciated.



Thanks.

Dave Yates (GrandPAH)

details

A thorough heat loss calc will reveal your home's heat loss on a room-by-room basis, although it will be a bit 'fat' to handle the CYA factor by a factor of about 10%. (Grants leeway for infil/exfiltration.) I'm really beginning to question if it's just 10% after finding our geothermal systems are not needing to turn on any electric resistance aux power to suppliment outputs during design conditions where we've spent weeks (instead of just a few days) this year.



Using that info, you can dial-in the actual highest temp required for the BB. Chances are it won't be 170F. Let's say it turns out to be on the high side at 160F for a design-day's night. Those low outdoor temps typically only occur for 3% to 5% of any given heating season. You might be out of condensing boiler temps for 20% of a heating season, but it's not just the condensing side of a modcon that grants better efficiency - the mod(ulation) side tweaks efficiency too and you'll still be modulating during that 20% ride.



Bottom line: modcon & BB do play well together. Slant Fin has a nice chart showing the BTU output per foot at varying temps down to a low of 110F last time I looked. Once you define the hottest water temps required, drop in a reset curve with a lower-limit of 110F and you're good to go with projected savings of 30% and higher.



Typical cost diff between non-modcon & modcon is $2k (or slightly less). Let's say 30% of your existing gas bill represents $500.00. $500 divided by $2,000 reveals your ROI (return on investment) in the first year will be 25%.



Still not convinced? Good. Let's take that $500.00 first year savings and add 5% to it each year to represent the rising cost of fuel over time and run the numbers out to the 20th year. You will have saved $16,532.98. The modcon will more than pay for itself!



I look forward to the day when an apprentice in our trades has to ask "What's a chimney?"  A hole in a wallet through which money can escape a building.   

Jean-David Beyer

Modulation experiments with baseboard and modulating boiler.

"Bottom line: modcon & BB do play well together. Slant Fin has a

nice chart showing the BTU output per foot at varying temps down to a

low of 110F last time I looked. Once you define the hottest water temps

required, drop in a reset curve with a lower-limit of 110F and you're

good to go with projected savings of 30% and higher. "



Since I am not a professional, I tried experimenting around with my baseboard heating reset curve so as to get maximum condensation and still satisfy the thermostat. My baseboard heating is oversized (14 feet of Slant/Fin in a room that loses about 3300 BTU/hour when it is 0F outside, and the design day is really about 14F). I had that excess baseboard installed to promote condensing.



I first thought to run the reset curve between about 80F and 135F. And I probably get condensing all the time. But using the low end of 80F, while promoting condensation, results in so little heat delivery from the baseboards, that the boiler cannot modulate down that far. This results in running the boiler in bang-bang mode that is probably not too good for it. Experimentally, I came up with about the same 110F figure you suggest, not because that is the bottom of the Slant/Fin table, but because I needed that much to get the cycling rate low enough.

Glen_7

Update

Dave,

Thank you for your detailed response. Having lived in the house this winter, and experiencing some cold days, I can say that the current 180 degree water I have running through the baseboard is pretty much needed. On days when the temp would drop below 20, the rooms struggled to stay around 70 even at that.

Does this change the equation?  I'm not looking to rip out or highly modify the BB in the rooms that are not getting radiant.



Thanks.

Glen

Dave Yates (GrandPAH)

not much

Not very much, but it does lead us to the next logical step - an energy audit that includes a blower-door test. Most homes lose 40%, or more, of produced energy that's initially retained (not lost to the chimney via combustion) just via air leaks in the building envelope.



Aside from windows & doors - where everyone first looks - there are probably lots of unseen (although an infrared camera can see them) leaks you could seal up using foam or silicone calk. Call it death by a thousand cuts, but when totaled up all those minute gaps, holes, saw-cuts, etc. make a huge difference.



So, what you're really looking for is a rare bird indeed - a mechanical contractor who has those combined skills and one who is willing to invest the time required. More than a few come here, so you might want to give your geographic area location and check the contractor-listing search-engine Dan has in the links above.



Once you've done the due diligence to tighten up the structure, your BB temps will be lower and that's then the time to study the relationship between feet of BB compared to each room's heat loss. One of the rooms will probably be the underachiever (slowest student in class) that dictates upper water temps, and if that's the case, you can add another few feet of BB or another type of heat emitter to bring the poorer performing room(s) into line. Bear in mind you'll be moving from a fat sloppy wide four-lane hydronic roadway that had a boatload of leeway to a modern sleek Euro-rail hydronic system that has little fat, but lots of room to tweak the amount of delivery-comfort-energy.



The radiant zone(s) will require mixing strategies, but they can be as simple as a 3-way mix if your main system is on outdoor reset. Variable-speed circs can dramatically cut your wattage consumption too, but your installer will need to pay close attention to the modcon's needs for flow.



You're not looking for a run-of-the-mill low-bid contractor based on what you've described, but one who can craft a green energy-saving system (with emphasis on "system") that will allow you to keep more of your hard-earned money to devote to investing, fishing, or spending time with family. A gold-metal Olympic-caliber contractor!   



This may help: [url=http://www.energystar.gov/index.cfm?c=diy.diy_locating_leaks]http://www.energystar.gov/index.cfm?c=diy.diy_locating_leaks

Glen_7

Thanks Dave

This is a circa 1920's home. The attic has blown insulation but the walls are balloon frame and have no insulation. I will be having the sill area sprayed with foam, which I can feel is a large part of the infiltration. It will help the chimney effect through the walls. I have storm windows throughout except for the living room, which has its original leaded windows which I will not be tampering with. I am willing to pay some extra cost to maintain the architectural integrity.

I am also looking to swap some of the regular BB with cast iron BB. I have that in one room and the comfort level is far superior to the finned BB. I know the BTU output is about the same, but the "feel" is much better.

Looking forward to this project and finding the right guy to do it.

Thanks again.

Glen

djthx

HW Cast Iron vs BB

When you first posted that you have 6 BB zones, did you mean that you have 6 independent zones (with 6 thermostasts)?  If not, and if you have both BB and a HW radiator running on the same zone, then I would imagine that the HW might "feel" better because the cast iron retains more heat for a longer period.  I would think that you should not mix BB and CI on the same zone for this reason. 

Glen_7

Baseboard

Yes, I have six separate zones with six thermostats. The one cast iron room is strangely on the same zone as two rooms with finned. It is a smaller room (bathroom) but the feeling of the heat is so much nicer. That, plus cosmetics, is the reason I am considering switching out the finned BB on that area to be all CI.

TonyS

I am not so sure I agree

with Daves math. I just replaced my first Peerless Pinnacle inducer fan...over 7 bills my cost!!!! There is no doubt if you are burning thousands of dollars of fuel, you will see a return. But I doubt you are going to see 30% savings with a mod con over lets say a Burnham ES2 with ODR. So lets say you burn 200.00 bucks a month in fuel for 5 months a year and you gain 15% with a modcon. Maybe you live in Virgina or Maryland or maybe you live in Maine...I dont know. You save 30 bucks a month for 5 months a year....150.00. You know when you install the cast iron boiler its going to be there until you are tired of looking at it. You know when it breaks down it will be minimal to repair. The modcons are expensive to repair.  You have to ask yourself, if modcons are the greatest thing since sliced bread, Why does Buderus and Viessman sell so many cast irons in Europe. Now go to Ebay UK or Deutchland if you can speak German and look at the price difference between modcons and Cast. The cast iron boilers are more!! Now you have to ask yourself why would these people with such high fuel cost and concern for their environment choose to pay more for a cast boiler, I dont believe they are stupid. They have lived with this stuff for a while, I think they might know something we don't. While your shopping ask the shop how much it would be to replace certain parts, inducers, electronic controls, ect.

Gordy

How Old?

How old is the Peerless Mod/Con?  Did you do yearly maintenance?



  Any product you buy could have more problems than another in the same line. Not just in boilers either, its across every product spectrum you buy.



 I do think maintenance needs to be thrown into the ROI though.



Its not all about buying an appliance that burns less fuel to save the consumer money. Its also about buying one to save all consumers buying fossil fuels money, by decreasing demand on whats left of fossil fuels.



 Your not going to find a lot of boilers of any kind that will last like the old cast iron behemoths. The business model is not stupid they know they need to sell boilers to stay in business.





I can't explain your European Ebay analysis. My Uncle lives in Italy mod/cons are big along with the mind set of being energy efficient. They have the boiler police there he needs yearly inspection by the Gov. to make sure the boiler is running in tip top shape.





Gordy

TonyS

6 years old

Yes it was seasonally maintained. I dont care if the plastic impeller

was made of gold!!! 7 bills is a rip off!! Natural gas can be

considered a fossil fuel but it is domestically produced and we now

have standing reserves at over 100 years. If you buy into the whole

global warming thing, where doe it stop. Should we take away peoples

pleasure boats? How about recreational flying, should we stop it to

save the earth. I would like us to become independent of foreign oil

because of wars not because I buy into this Gore crap.  Like I

said...if you are burning 1000.00 in fuel a month and can save 150.00 a

month that makes a better case for a modcon.



I started in this business with my father when I was 17...Thats thirty

years ago and I still maintain boilers we installed then. They are all

cast iron Weil Mclains and Burnhams, they werent behemoths,close to if

not the same size that they are now and they still work fine. My ebay

analysis is just fact, it takes about 20 seconds to verify this fact,

just a click away. Maybe someone out there is more familiar with

Buderus and Viessmans. Who are they selling all these cast iron boilers

to? A good cast iron boiler is still a solid investment. Just my opinion Gordy.

Gordy

Tony

I don't totally disagree with what you are saying. But there are times when modcons have failure which is due to incorrect installation, I think you know that.



As far as the ebay analysis sounds like you are on to something. I have never thought about seeing what homeowners are doing in other countries with their heating plants. Whether you stumbled on to this by accident, or deliberately decided to research it is an eye opener, and a different way of analyzing the market in deed.



I do agree with the fact that the higher your existing fuel bill is now the more ROI you will gain on a modcon.  If you are shelling out high fuel bills now. Your money is most certainly better spent tightening up the structure to reduce heatloss, than trying to make up for it with a more efficient boiler.



I do disagree RE your thoughts on our fossil fuel reserves. I'm not a tree hugger, or an Al Gore backer. I think global warming would come, and go even if we as the human race did not exist. But our fossil fuels are not endless. I'm thinking of my children, and grandchildren. Think of their implications if gas goes to 10.00 a gallon, or it costs 1500.00 amonth to heat your home in the winter if you can get fuel. Those days will come eventually, Hopefully we will have a solution before that. Maybe a fossil fuel tax for pleasure burning is needed.



Gordy

Glen_7

System 2000

Thanks to everyone who has responded to my original post. After reading about my current and proposed heating configuration, would a System 2000 be a good choice? I see lots of opposing views on these but a lot of the end users feedback is generally very good. Less maintenance than a mod/con but better efficiency than CI??



Thanks.



Glen

TonyS

Ive never used the system 2000

but I just watched their video. Its kinda filled with half truths and they compare their unit to systems that are less efficient. They are basically using a low mass boiler and post purging the heat. Nothing too special about that. I don't like the idea of using a gas power burner if there is no need too. Low mass is not always your best bet, considering you said you have 6 zones. Without any thermal mass you will tend to get short cycling on the smaller zones. You can post purge a boiler with a 2 stage stat but if the heat is lost inside the structure or even into the boiler room where you want a little heat then there is nothing really lost. I did a a job where the people wanted the old gravity mains insulated, I told them..not a good idea, but they wanted it because they only used the basement to do wash. Not only did the basement become unbearably cold but also the floor on the first floor became cold which made them turn the thermostat higher to keep the same level of comfort. Needless to say by the next time I came to clean the boiler, most of the insulation was removed. I dont believe system 2000 is using a outdoor reset, not that you couldn't add one. On the other hand they seem to have a good warranty and I like the idea they are using off the shelf parts. I would recommend finding a professional in your area that you feel comfortable with.

TonyS

Gordy

This is what really gets me with these modcons. Here is a price that includes a boiler and INSTALLATION for $2238.00!!!!!!!!!!!!!!!!!!     http://cgi.ebay.co.uk/Viessmann-Vitodens-26KW-Combi-Boiler-Installed-1500_W0QQitemZ220558211564QQcmdZViewItemQQptZUK_localservices_tradesman_GL?hash=item335a4b39ec

TonyS

The minimum wage in uk

is 8.23 an hour. Just for perspective!

CMadatMe

I have to Disagree with you Tony

Concerning the ES2. Add the price of the reset card, low water cut-off card and the chimmney liner and the price is right at a mod/con. Dave hits the nail on the head when he say's start with a heat loss. Very little investment to see what application fits here. My advice would be the same as Dave's. Have a heat loss done, measure exisiting heat emmitters per zone and do some math. If there is a zone that may be on the fence changing that particular zone out to hi-cap board could do wonders for your heating curve. For instance, with a 1gpm flow rate at 150 degree water hi-cap puts out 560 btu's ft comparable to 180 @ 1gpm for residential board.



We can all sit here and argue but without that heat loss and emitter capability we really all can't give an honest opinion so my vote is for Dave's advice.

TonyS

Chris

Let me better explain myself. I do agree with Dave 100% about the heat loss and the procedures he describes. What I am not so sure about is the payback the modcon will give when maintenance is figured into the equation.

Gordy

across the pond

Looks like a grand or two is what it takes to get these boilers excepted, and shipped to the United States. All though still cheaper than comparable US brands,if anything compares to the big V.



Gordy

TonyS

Chris, here is a price on an ES2

It appears to have the reset control and low water included.  http://www.pexsupply.com/Burnham-ES2-4-ES2-4-105000-BTU-High-Efficiency-Cast-Iron-Boiler   

CMadatMe

Pricing

Tony one of the rules here is that we not discuss pricing. I can tell you based on 1st hand knowledge that I am willing to bet if you call them that price is less the cards and you cannot use an internet based company to gauge the price. Call 4 local wholesalers in your area and get a price. What value does that internet based company have or can offer you? Will they be there when there is a warranty issue?



I have to be missing something about the maintenance issue. I don't care what piece of equipment you install there is always preventative maintenance. If I as a consumer am paying top dollar for a piece of equipment that is suppose to be the best don't ya think I might want a service contract and would be willing to give you my money up front for that? The maintance argument to me is petty.  A properly designed system with a mod/con is going to give you far more of a payback. The payback isn't the total cost it is the cost difference between 2 products plus you must take into consideration the federal tax credit and any local utility rebates.



In the end it is educating your customer and giving them a chance to make a decision based on the heat loss, emiiters, etc.

NRT_Rob

I disagree

with the statement that cast iron will last "until you get sick of looking at it".



I had a cast iron boiler fail... actually fail, leak through... that was only 12 years old in my home, not too long after i bought it. on a baseboard system.



modern cast iron is not the same as 60's cast iron, IMO.



I think $200/month in fuel is fairly low in any real winter climate.



and I think 15% is being generous to the cast iron.



I do think some mod/cons are more expensive to service than others and I think that complicates this discussion. but there are several out there with proven track records at this point that would seem to be not significantly more to service than cast iron is.

TonyS

Believe what you want to believe

I just finished a UK review of 52 modulating boilers. Most I never heard of, many that are sold here. They were rated on price, durability, efficiency. They are all about the same price except for a few of the premier units 900 to 1400 bucks. They bring alot of this stuff here then they start the mantra, telling you about the super stainless( off the shelf alloys), the Lambda sensor (mass produced o2 sensor) and they convince even intelligent men this stuff is super special. Its not They are mass produced stampings( except for the Prestige which uses state of the art robotic welding) that should have a retail value of about 900 to 1400 bucks. The one thing they are doing in UK is actually getting them into everyday peoples homes and you can bet when they break down they arent getting over a grand to install an inducer motor. Im tired of seeing the working class in this country get whipped down. I believe Dans rule here about pricing doesnt  include pricing that is already public information on the internet. I know how you feel, Sure customers that just dropped 8 grand on a Vito 100 probably are thinking that maybe their unit isnt as super as they thought. I can tell you the guy who is about to pay me over a grand to replace an inducer on a peerless pinnacle  is just as unhappy. Corporate greed has no boundaries!

NRT_Rob

I don't like their sales tactics

but the system 2000 delivers better efficiency than regular cast iron. Brookhaven proved it. vs a mod/con with purge control and/or a buffer tank though, I think it doesn't shine as hard as they seem to think.