80% AFU I don't think so...

Steamhead (in transit)

the Canadian variant of the Ideal Redflash. Dominion Radiator Co. was the second name used for American Radiator Co.'s subsidiary in the Great White North. The first one was "Sirdar".

Boilers of this type had wide flue passages designed for coal firing. These are not suited to burning gas or oil, since the hot gases shoot thru the center of the flueways and don't make good contact with the cast iron surfaces. It's possible to baffle these passages to slow the gases down and improve contact. This will improve the situation but will not equal the efficiency of a newer design.

Off the top of my head, I'd guess the new boiler you're considering might cut your fuel consumption by about a third if the flue passages in the Domrad are not baffled.

Three things to consider: 1- Size the new boiler to your heat loss, not to the radiation.

Second- it would be a good idea to get an oil-fired boiler and put a gas conversion burner in it. This way if gas gets or stays much cheaper than oil, you can just change the burner and have a tank put in, and burn the cheaper fuel. And you can switch back to gas if oil gets more expensive again. Note that the changeover must be done by a pro, they don't make combination burners for residential boilers- yet.

Third, make sure the circulator on the new boiler is sized properly for the old gravity system. Go here for specifics:

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Michael Rogers

Checking out my boiler I noticed that different techs. note different eff. on different years. I can't see this old coal burner conversion getting anywhere near this eff.. Also there btu seems really off, as I did a heat loss calc. and the replacement boiler will need to meet 65,000 btu/hr load at -15°F with a sys. temp of 170°. This is still a gravity sys. but new boiler will be pumped. Also the water temp now does not even get over 100°f, there is no temp. guage but I thermal scanned the rads. and pipes. All this makes me think that the eff. is NOT 75-80%. What do you think?

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Leo

Eff

They are talking combustion efficiency or the efficiency of your burner as opposed to thermal efficiency or that of your boiler. Testing the boiler isn't something that can be done in the home. As far as efficiency differing from year to year on the burner it is similar to gas mileage in a car which can vary. Weather conditions have a lot to do with it considering temperature, air density etc.

Leo

Ron Schroeder

Also

take into account that if your putting out cooler water and cooler return water this will cool the flue gases givig a higher effy readings if you were to heat the boiler to 180* your effy would probably go up

GaryDidier

Mike

I typically achieve combustion effs. of around 80% on these types of boilers. While they have wide open flue passages like steamhead says they also have a lot of mass to soak up the energy if water temps are kept low. Sometimes when these systems are changed out the basements become much cooler due to the lower heat loss of the new equipment. I also agree the new equipment should be rated for oil so you have a choice of fuels in the future.

Good luck,
Gary from Granville

Michael Rogers

I am looking at a Buderus that would also serve our domestic HW needs. I not sure if it is rated for oil but I will check. It seems that fuel costs here in Canada do not seem to be as shocking as those in the US.

Steamhead (in transit)

Mike, Buderus makes both

oil and gas boilers. I don't know if they offer a gas conversion burner for their oil units, but there's no harm in checking.

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Mark Hunt

Mike


You have already listed all the reasons for you to go with a gas fired modulating/condensing gas boiler.

Do not bother looking into the oil/gas power burner option.

You can heat your home with 100 degree water. You are a perfect fit for a gas mod/con boiler. The GB-142 will save you a ton of money.

Mark H



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Mark Hunt

Frank


Would you not agree that this gentleman's situation is a perfect fit for modulating/condensing?

Should everyone install an oil boiler with a gas conversion burner "just in case"?

Please explain.

Mark H

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Michael Rogers

The GB-142 is one of the ones that I am considering. Efficiency is of great concern but so is initial cost. The company I work for has accounts at many wholesalers. I have gotten a price of $1300 CAN. for Weil-McLain CGa-5, but after my heat loss calc. that is too big. I have yet to get prices on Buderus and Biasi.

Steamhead (in transit)

Cost per BTU

is the factor here. You have to weigh the price for each fuel, then decide. With gas so much more expensive than oil in many areas, it's hard to justify staying with gas. Since the future is so uncertain it makes sense to have multiple-fuel capability.

Then there's Boilerpro's mod/con customer who went for three weeks without heat waiting for parts, because the idiots who run that company shut down for inventory in the middle of the winter. I will NEVER put one of my customers in that position. I've quit buying any of that company's boilers.

And if you check the AFUE figures, it would seem that an oil-designed wet-base boiler with an inshot gas burner would be a bit more efficient than the usual atmospheric gas boiler.

I'm not knocking the mod/con concept, but they have to be more reliable and better supported.





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Mark Hunt

I can tell you this

Even if you get a price for $2 Canadian for any boiler, it will only perform to the level of the installer, and you may get a wooden nickle installer. That could ruin any boiler.

A word of warning here Mike. You go ahead and find a "wholesale" price for whatever boiler you want, but if you use it as a shoe to beat the contractors that bid your project you will end up in a sorry position. So you may know YOUR cost on a piece of equipment, but do you know the contractors cost of doing business?

Do you have a pre-set dollar amount of what a heating contractor is worth? Are all heating contractors the same?

Be very careful here Mike. I see HUNDREDS of posts like this on The Wall every year. Customer wanted a Ferrari but paid for a Yugo. They end up back here asking why the "top of the line" equipment they bought doesn't work. 9 times out of 10 they bought the right equipment but hired the wrong guy to install it. The manufacturers genius stops at the shipping dock.

Mark H



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Mark Hunt

In certain areas

I guess that is key, no? Where I am sitting, Nat. Gas is cheaper than oil. LP is about even. Those are $/btu numbers.

But you already said that units designed to burn coal have larger flue passages and are therefore not a good application for gas conversion burners. Would the same not be true for units designed to burn oil as opposed to gas?
And if that is the case, how much fuel will be wasted by those gas conversion burners in the mean time waiting for the huge jump in gas prices? Is it possible that a practice like this could actually be a catalyst for the jump?

I hope you will agree with me on this Frank. Don't you think it's time we started calculating REAL efficiencies rather than what was obtained in laboratory experiments?

Mark H

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Michael Rogers

Well I really am not to worried if I spend 2000 or 3000 or more (within reason), as long as I am getting the best for my buck. And my "wholesale price" is because I am a tradesman and deal with wholesalers. I am an electrician but will be doing the install with a heating/boiler tech. that I have worked along with for many years. I am really just trying to get the best system for my dollar without bothering him too much. Really I am just trying to figure if I should go with a mod-con. or a more conventional boiler for my gravity conversion, without sealing the envelope of the house right away (long term project). Most here are very smart and inciteful people and I enjoy reading all that is said.

Steamhead (in transit)

In the case

of a pin-type heat exchanger, I doubt there'd be much difference. It was a gas design originally and was adopted for oil. Not sure what a three-pass design would do. But I've read somewhere, can't remember exactly, that power gas burners are noticeably more efficient than atmospheric ones. That plus a wet-base boiler looks like a no-brainer to me.

The only reasons I can see for the continuing use of atmospheric gas burners in heating equipment are: 1- they're cheap, and 2- they preclude switching to oil. This has to be why gas utilities love these units.

We'll probably be doing an installation of this type soon. The lady was spooked by the sharp rise in natural gas prices and wants flexibility. This will probably turn into a demonstration project like my other ones.

Mark, I agree 100% that we need to increase the efficiency of our customers' systems. But we need to do so without compromising the reliability and support they've come to expect. The recent parts availability problems I mentioned is only the latest episode. We've seen it before and probably will again. Some of these are starting to look as bad as the American auto industry, with their recall after recall after recall.

Realistically, the only mod/con boilers out there with any kind of good long track record come from Europe, and these are high-dollar items that not everyone can afford. Plus, they're almost all gas. The same will be true with the low-sulfur oil-fired mod/cons when we finally (well behind the rest of the world) require low-sulfur fuel oil. Yes, I'd prefer to buy and install American, but I dislike using my customers as unpaid product testers.

I have to think about myself as a customer. If I had a truck, for example, that broke down frequently and required long waits for parts, I'd look for another truck. Wouldn't matter to me how many miles-per-gallon the truck got, if I couldn't work with it. And if a certain dealer was pushing the sale of these unreliable trucks, I'd go to a different dealer. I bet you would too.

I don't mind trying something out in my own house. Many of us are doing just that and I'm watching. When low-sulfur becomes law, I'll be the first on my block with a new high-efficiency oil-fired boiler. It will go in right next to Old Reliable, my V-14. That way if the new boiler breaks down, The Lovely Naoko will still be warm.

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