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Old 10-16-2011, 11:33 AM   #1
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Cast iron vs mod/cons


A buffer tank, a storage tank and a indirect are all similar, but different. An indirect has a pipe heating coil that the boiler runs its hot water thru, and that coil transfers the heat to the water in the tank. It is an "indirect" because the heat transfer is indirect, as opposed to a hot water heater that has a flame (direct) that warms the water. Storage tanks have generally been used in large buildings where there is a large demand for hot water, such as an apartment building.

A buffer tank serves two purposes in a heating system. It creates a hydraulic separation between the boiler side and the system side in your house. But let's talk about the other advantage, because that is the one that saves you money. You get your biggest savings when you have small zones in your home. The ideal heating system would produce the exact number of btus that your home is losing at any given moment. Let's say you have 4 zones in your home, and a 100,000 btu boiler. It is September, and one of your zones calls for heat, but since it is 58 degrees and cloudy, the zone only is losing 1500 btus an hour, but the boiler is producing 100,000. A small zone may only have less than 3 gallons in it + another three in the boiler, so it does not take the boiler long to heat the water. This causes the boiler to cycle on and off too often which is hard on the boiler and it wastes energy. A 95% modcon can modulate down to 25% meaning it will produce 25,000 btus, but this is still a lot more heat than the 1500 btu zone needs. Even the modcon is producing 16 times more heat than the zone needs. A lot of heating guys just don't get this. To make matters worse with a modcon, they purge their vents before the heating cycle and this wastes energy and is hard on the boiler. If you have a boiler heat a 80 gallon buffer tank full of water, and you have a Honeywell L4006A aquastat, you can set the aquastat to turn off the boiler at say 160 degrees. Then when a small zone demands heat, it will take its water from the buffer tank. These small zones could cycle on and off a number of times before the boiler comes on again because you can set a differential temperature on the aquastat of 10 or 15 or even 20 degrees or more. If the high limit of the aquastat turns off the boiler at 160 f and you have a differential of 15, then the boiler would fire when the water in the tank reached 145f.

A well insulated buffer tank such as the ones at www.heat-flo.com, account for only 2-3% of your heating bill, but do a lot more in the end. I am going to buy an 80 gallon AO Smith uninsulated horizontal tank because of cost + my ceiling is only 60" in the boiler room. It would produce heat to the equivelent of a 3 foot long, 6 tube radiator that is 9.75" wide and 20" tall. In other words, I would be using it to heat my basement, and it would be under my family room which has a lot of windows. It, therefore adds zero to the cost of my heating bill, not even the 2-3% mentioned above.

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Old 10-16-2011, 11:51 AM   #2
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Cast iron vs mod/cons


Some heating guy will come to your house and tell you that he will "save" you 30% on your gas bill by installing a 95% efficient furnace.

I want you to buy an 84% cast iron boiler, and I will show you why your thinking, right now, is wrong. 95%-84%=11 divided by 95%=11.5 This is what your 95% afue rated boiler will save you over the cast iron boiler. A 95% boiler requires you to have someone come in to likely change the ignitor, clean and inspect the boiler at a cost of $300 per year. If your heating bill was $1500 last year, you have saved 11.5% on the cost of gas, or a $172.50, but you have spent $300 in maintenance. The reason anyone saves 30-50% on their heating bill is all the other stuff such as insulation, windows that don't leak and also how the boiler is installed. It is how the "nearside" piping is installed that usually saves you money. In your case, you will save more by insulating and windows. I have lived in houses that where 1930s and older. I have had most of the old windows caulked and painted shut to eliminate any drafts, and then use my doors for air circulation. I have a lot of windows in my house and they account for 40% of my heat loss.

I think I put my design in an earlier post which shows to modulate the system using an inexpensive valve. And don't buy anything until you insulate and replace the windows. Stick with the munchkin clunker until you do your windows and insulate.


Last edited by rickmay; 10-16-2011 at 11:54 AM.
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Old 10-16-2011, 12:03 PM   #3
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Cast iron vs mod/cons


and bill.

If you have all large cast iron radiators and no baseboard or no in-floor heat, you are being conned. I have 7 large radiators in the front of my house, and that part of the system with its pipes holds 70 gallons of water. If you had a 80 gallon buffer tank, it only cuts the cycling in half, and is not worth the extra cost.

Where you would really save would be to install a 3 or a 4-way valve that modulates you system water based on doing an outdoor reset. Go to Taco-Hvac.com and look for their iSeries mixing valves and look at how they are piped. You can lower the temperature in your radiators greatly when it is not so cold out, and it is all done for little money. A modcon, by itself, probably would not even save you the 11.5% mentioned above if you have all large radiators.
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Old 10-16-2011, 12:50 PM   #4
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Cast iron vs mod/cons


Quote:
Originally Posted by rickmay View Post
and bill.

If you have all large cast iron radiators and no baseboard or no in-floor heat, you are being conned. I have 7 large radiators in the front of my house, and that part of the system with its pipes holds 70 gallons of water. If you had a 80 gallon buffer tank, it only cuts the cycling in half, and is not worth the extra cost.

Properly sized mod/con wouldn't need a buffer tank,.

Where you would really save would be to install a 3 or a 4-way valve that modulates you system water based on doing an outdoor reset. Go to Taco-Hvac.com and look for their iSeries mixing valves and look at how they are piped. You can lower the temperature in your radiators greatly when it is not so cold out, and it is all done for little money. A modcon, by itself, probably would not even save you the 11.5% mentioned above if you have all large radiators.
No reason to heat the water up to higher then what the rads need to heat the house. A mixing valve only lowers the temp of the water to the rads, still requires the boiler to heat the water hotter then it needs to be, increasing standby loss, and wasting fuel.

Buffer tanks don't save money on heating cost. Their used as a security blanket for over sized boilers.
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Old 10-16-2011, 01:23 PM   #5
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Cast iron vs mod/cons


Weils warranties for the cast iron are "lifetime," where the other stuff is 20 years. This tells you what they think the life will be. Why replace it twice. I would also like to point out how many difference versions Weil and Burnham have put out in the last 15 years trying improve efficiency. It tell you that they are not happy, themselves, with their solutions.

How can you say that a modcon doesn't need a buffer tank. I just gave an example where the buffer tank would cut down on the cycles by a very measurable and realtively high number. Unlike a cast iron, your modcon would be doing purges of the flue, before and after every time it cycled, and that is what wastes money.

Do you have a modcon, beenthere?
Do you have radiators or baseboards in your home?
How large is your home?
Is it insulated?
How much was your gas bill last year?
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Old 10-16-2011, 03:00 PM   #6
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Cast iron vs mod/cons


Quote:
Originally Posted by rickmay View Post
Weils warranties for the cast iron are "lifetime," where the other stuff is 20 years. This tells you what they think the life will be. Why replace it twice. I would also like to point out how many difference versions Weil and Burnham have put out in the last 15 years trying improve efficiency. It tell you that they are not happy, themselves, with their solutions.

It tells us they have trouble making an efficient and reliable cast iron boiler. Plus, their warranty is pro rated, in the 11th year the owner starts to pay a percent of section cost.

How can you say that a modcon doesn't need a buffer tank. I just gave an example where the buffer tank would cut down on the cycles by a very measurable and realtively high number.

Simple, a properly sized one doesn't need a buffer tank. Too many people confuse cycling and excessive cycling and short cycling as all being the same and having the same effect.

Unlike a cast iron, your modcon would be doing purges of the flue, before and after every time it cycled, and that is what wastes money.

Most 85% boilers do a pre and post purge. So thats a mute point

Do you have a modcon, beenthere?
Do you have radiators or baseboards in your home?
How large is your home?
Is it insulated?
How much was your gas bill last year?
I have oil fired hot air heat.

However. I have Plenty of feed back from my customers on how their mod/cons are working(none of them have buffer tanks). I have mod/cons installed on copper baseboard in apartment building that exceed 30% savings over any of the cast iron boilers in any other building of the same or smaller size they have.

Even better savings on apartment buildings with large cast iron rads.

I do this for a living. And I service what I sell and install. So I know the history of the equipment I install. And that history exceeds 13 years of mod/cons.

How many boilers have you installed, $ of cast iron and # of mod/cons.
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Old 10-16-2011, 08:17 PM   #7
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Cast iron vs mod/cons


I spent the day crawling under my deck to install an electric line to my boiler from the corner of my deck where the generator will be secured. We have had too many power outages in the Chicago area and they are getting longer. The last one of length was 3 days. I do not want my food to spoil and more importantly, I want heat.

With regards to modcon v. cast iron simplistics, it is not worth the discussion. Boiler manufacturers, if they want to show that there is actually a savings should install two systems in two identical homes. I doubt that will happen because I don't think it will justify the added expense and maintenance of a modcon.

Earlier, I suggested that the heating guys in the northeast had a small cult going. I am going to modify that, and say it is a hobby. You guys go nuts trying to save every penny in natural gas regardless of the labor and install cost. You do have some decent installers out there, but, in Chicago, it is not worth the chance. I never see a complaint on the internet on an 80% cast iron boiler, but there are loads of issues when modcons are installed. I don't want a boiler that needs maintenance with the hope of saving some money. I want a boiler that will give me heat day in and day out doing little to it, knowing that I don't have to pray for the heating guy to come to my house when it is -15f and my pipes are freezing.

If anyone needs to justify a savings, it is the installer of modcons. They cost over twice that of a cast iron, they have a guaranteed annual maintenance expenses, they break down a lot more often, the parts are more expensive, the warranties are 50-60% that of a cast iron, and their expected lifetimes are a lot less. Stainess, plastic, aluminum, computers just do not hold up like cast iron.

Great strides have been made on the system side of home heating, yet installers give the credit to the boiler that saves some gas. It is a nightmare for any homeowner to lose heat in the middle of winter (-26f in Chicago, a number of years ago), so, for me, I can rest comfortably knowing that my cast iron will keep on working, and I won't be saying a prayer for my ill-trained repairman to show up and fix everything before my pipes start freezeing and I have to drain my toilets and the whole plumbing system. No thanks.

Last edited by rickmay; 10-16-2011 at 09:37 PM.
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Old 10-16-2011, 08:30 PM   #8
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Cast iron vs mod/cons


Many people like to justify staying with cast iron. Thats fine. In truth. Mod/cons are reliable. And all boilers are suppose to have yearly maintenance.
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Old 10-16-2011, 08:37 PM   #9
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Cast iron vs mod/cons


Quote:
Originally Posted by rickmay View Post
I spent the day crawling under my deck to install an electric line to my boiler from the corner of my deck where the generator will be secured. We have had too many power outages in the Chicago area and they are getting longer. The last one of length was 3 days. I do not want my food to spoil and more importantly, I want heat.

With regards to modcon v. cast iron simplistics, it is not worth the discussion. Boiler manufacturers, if they want to show that there is actually a savings should install two systems in two identical homes. I doubt that will happen because I don't think it will justify the added expense and maintenance of a modcon.

Earlier, I suggested that the heating guys in the northeast had a small cult going. I am going to modify that, and say it is a hobby. You guys go nuts trying to save every penny in natural gas regardless of the labor and install cost. You do have some decent installers out there, but, in Chicago, it is not worth the chance. I never see a complaint on the internet on an 80% cast iron boiler, but there are loads of issues when modcons are installed. I don't want a boiler that needs maintenance with the hope of saving some money. I want a boiler that will give me heat day in and day out doing little to it, knowing that I don't have to pray for the heating guy to come to my house when it is -15f and my pipes are freezing.

If anyone needs to justify a savings, it is the installer of modcons. They cost over twice that of a cast iron, they have a guaranteed annual maintenance expenses, they break down a lot more often, the parts are more expensive, the warranties are 50-60% that of a cast iron, and their expected lifetimes are a lot less. Stainess, plastic, aluminum, computers just do not hold up like cast iron.

Great strides have been made on the system side of home heating, yet installers give the credit to the boiler that saves some gas. It is a nightmare for any homeowner to loose hit in the middle of winter, so, for me, I can rest comfortably knowing that my cast iron will keep on working, and I won't be saying a prayer for my ill-trained repairman to show up and fix everything before my pipes start freezeing and I have to drain my toilets and the whole plumbing system. No thanks.

Wow, nice rant!
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Old 10-16-2011, 09:35 PM   #10
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Cast iron vs mod/cons


If I was installing 100-180 systems every year, I know I would not want to carry a 300-500 cast iron monster down the basement stairs. I would defend modcon, also, given a choice for the next 30+ years.

I am beginning to think that the heating business is only one step above the funeral business. Doc, I hope you are not in that business. For every post like mine there are 100 of those installers that want to perpetuate modcons like those Prius modcons. Want a real car, go diesel with cast iron. VW is pushing 800 miles in a tank, but they cannot get their act together. If it isn't the heating system, it is something else. As for me, I do not want problems.

In case anyone wonders, the low point on the totem pole is the scum in Washington, and those that control them.
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Old 10-17-2011, 05:42 AM   #11
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Cast iron vs mod/cons


Its getting the old over sized cast iron piece of junk out that is tough.

Mod/cons are here to stay. There will always be some installers that hate them. And there will always be some home owners that don't like them. neither will have any true experience with them. But hate them just because they don't really understand them.

I took time to learn how they work and what they need to work correctly(which required more then just reading a book or website reviews).

The first 90% hot air furnaces met the same objections, and still do from time to time. Many people like to live in the past, and don't want to give up their old Beta tape players. An that fine for them. Misleading others into thinking that is how they should live also, is an injustice to them though.

Tin can probably use an Ultra UG 105 in place of his Munchkin140. And will find its reliability is much better. An it has a better outdoor reset built into it. That will allow tighter water temp control. And save him more on his heating bill over the Munchkin.
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Old 10-17-2011, 07:45 AM   #12
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Cast iron vs mod/cons


Bill you might have a reliable boiler, ask yourself this question have you been using the same Company for five years to clean, service and to inspect your boiler? Don't they have service contracts that include everything ? Maybe it's time to call in another Company to inspect, clean, service your unit. When a mechanic says to the customer I think it's this or that it's time to change Companies. I knew many people that had nothing but problems with their heating until they switched Companies then everything was OK. Mechanics are not all created equal. Most mistakes are paid for by the customer.
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Old 10-17-2011, 08:06 AM   #13
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Cast iron vs mod/cons


Have to agree with the quoted post below... I don't have any experience with boilers but I have seen this discussion many times before. Emissions controls, catalytic converters, fuel injection for cars... 1.5 gal toilets... 90+% hot air furnaces... lately compact fluorescent bulbs.

The new technology is always "the end of the world" to some, but once fully developed and dialed in works just as well as the old tech, or even better, and saves us a lot of energy/resources, which will help moderate energy prices for all of us. And make the world a cleaner place. 10% or 15% extra energy costs accrued by keeping an old inefficient boiler may not be that much of a hit to someone's own bottom line but when scaled across millions of users it makes a huge difference.


Quote:
Originally Posted by beenthere View Post
Its getting the old over sized cast iron piece of junk out that is tough.

Mod/cons are here to stay. There will always be some installers that hate them. And there will always be some home owners that don't like them. neither will have any true experience with them. But hate them just because they don't really understand them.

I took time to learn how they work and what they need to work correctly(which required more then just reading a book or website reviews).

The first 90% hot air furnaces met the same objections, and still do from time to time. Many people like to live in the past, and don't want to give up their old Beta tape players. An that fine for them. Misleading others into thinking that is how they should live also, is an injustice to them though.

Tin can probably use an Ultra UG 105 in place of his Munchkin140. And will find its reliability is much better. An it has a better outdoor reset built into it. That will allow tighter water temp control. And save him more on his heating bill over the Munchkin.
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Old 10-17-2011, 10:46 AM   #14
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Cast iron vs mod/cons


Wow.

I think this RickMay guy is hanging out on the wall too... just as whacky over there.

Just to clear up a few facts (and for the record, I don't sell or service boilers of any kind).

1. Modcon efficiency will run CIRCLES around cast iron. Hands down. Cast Iron WITH all the electronic control required to run it efficiently and cleanly... and it is required, that buffer tank is a sustained condensing event without it.... is still 10% less efficient AFUE and I haven't seen many sealed combustion cast iron units out there... that's a big loser too, atmospheric burning pulls air *from the envelope*. sealed combustion is probably good for 10% to 15% by itself.

2. There are bad modcons and bad modcon installs. Modern cast iron is not 60's cast iron though. I had a cast iron boiler in my basement, doing baseboard and DHW, and 12 years after purchase, it was dead. so much for the longevity argument.

3. Anyone claiming insultarp is "better than foam board" is laughably uninformed about basic heat transfer as well as all research to the contrary. Insultarp is absolute garbage that only stands up to a comparison to a fully uninsulated slab. I DO sell a competing product there, which I picked up only AFTER years of fighting insultarp simply on the basis of its absolutely pathetic performance as an insulation.

RickMay... you are not an expert and you do not understand these issues. I would have more patience but you just keep spouting this same tripe and the insultarp thing just really pushed me over the edge. If you want to talk about what you think your research is telling you, great, but obviously you have a LOT more to learn before you start passing yourself off as some kind of authority, please. You are doing a massive disservice to real people here.
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Old 10-17-2011, 10:50 AM   #15
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Cast iron vs mod/cons


been there, have you tried disassembling the boiler? 4 or 5 sections are easier to carry than the whole boiler.

And Raylo, I understand technology, and it is great if it works and it is not a sham. 1.5 gallon toilets would be great if you did not have to flush them twice. Fuel injection is great. The Prius is junk science. Much of this stuff is thrust on us because major corporations can make more money, all in the name of saving the environment. A CFL light bulb is supposed to last 7 years of so many hours per day. They last less than a quarter of that, and the ones with a bulb around the tube, do worse. Love that 6000 tons of mercury that gets tossed into the ground when we are done with them. And if the manufacturers cared about the environment with regard to CFLs, they would have come up with an avenue to dispose of the bulbs. Did you see that anywhere? Major corporations could care less about the environment. They show us this every day in countries that don't have our missbegotten rules meant to turn this country into a third world cuba. Why does McDonald's use plastic cups? If you are going to mandate something it should make sense. A 50 MPG diesel car makes a lot more sense that a Prius with its batteries. A/C and heat comes from an engine, so there goes the mileage if you want to be warm in the winter or cool in the summer. I sure would not want to be hit in one of those cars, as the sheet metal is not as thick as a Campbell's soup can. Most of this stuff is corporate driven, so they can sell you more stuff and sell you more stuff that needs servicing. My bro-in-law just replaced the driver's mirror on his 2000 Mercedes, and the repair was $700. That is real progress. Who is rippen whom? Wake up and smell the roses. Large corporations largely do not care about the environment and people. This is clearly shown in the way they do business in other parts of the world. The executives care about pollution when it is in their own back yard to some extent, and they care about it in general. It just happens to get lost when the bottom line is involved. I could come up with thousands of articles if I wanted to take the time.

http://foodfreedom.wordpress.com/201...for-biopiracy/
http://www.lookingglassnews.org/view...p?storyid=5806

Nike and Gap and child labor?

http://knowmore.org/wiki/index.php?t...ks_Corporation

http://www.mahalo.com/answers/is-the...ty-an-oxymoron

Asbestos is still alive and living in India due to large corporations.

Cow farts produce more greenhouse gases than our cars.

China burns more coal than the rest of the world and the gases spew out of their smokstacks daily (have you ever seen photos, or remember that their government shut down all these chimneys, as well as their businesses two weeks before the Olympics). But who is racing to get in on the action? Large corporations of course.

I am moving on.

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