What is the Difference

Unknown

The Buderus G 115 model 34 is a 120,000 output oil boiler, rated at 86%.

The Slant/Fin XL 30H is a 104,000 output oil boiler, rated at 86%.

Above about 86%, the gasses condense, so that's about the top limit for a non condensing oil boiler..

Noel

Radiant Wizard

What is the difference

between a Pin-type Boiler and a 3-Pass Boiler? Which one is better and why? I'm trying to make a decision on which boiler I would like to put in my home and the more information I can get the better.

kevin coppinger_4

what do ...

you have for heat. Steam, Hot water, oil, gas? kpc

Mad Dog

Pin-type is your standard cast Iron boiler

a 3 pass...Buderus comes to mind. It is the route that flue gases take on their way thru the boiler and up the chimney. Pin-type are good heat grabbers, but a 3 pass absorbs even more energy from the flue gasses. Mad Dog

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Mark Hunt

Those are


AFUE numbers.

Combustion efficiency numbers might read differently.

Not to bring up the AFUE argument again but if there is no difference between a standard pin type casting and a three pass, why would anyone even bother to make one?

Mark H

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Joe_13

Lower emissions

Biasi says lower NOX output. Probably a requirement in Europe. I was also under the impression that pin type boilers are more difficult to clean. The larger surface area must make it better for heat transfer.

Unknown

Yep, you're right

But both are tested the same.

Combustion effeciencies are also the same.

Some of the old 60% coal boilers are 3 pass.

What is your point about the testing process, as long as it is apples to apples?

The TYPE of boiler doesn't make one more effecient than the other, nor does the price, or the type of iron.

As you know, the combustion products and temperature give you boiler effeciency, and neither type effects system effeciency directly.

What does effect system effeciency is a way to mix cold return water straight into the boiler, and the ability of a boiler to directly heat water to the system temperature without mixing it down after the boiler.

Those aren't iron boilers.

Noel

Rudy

One difference

Both pin type and three pass heat exchangers are trying to increase surface area of the heat exchanger.

Three pass boilers inject a flame into (simply described) a horizontally-oriented, double-walled cylinder, that is filled with water between the walls. The fire passes inside and around the outside of the water filled cylinder. It's a little more involved than that, but you get the idea.

Pin type heat exchangers are like water-filled waffles standing vertically with the burner flames under the bottom of the waffles, flames passing between them.

Picture what happens in older systems if sediment ever develops inside the water side of the system.

In the pin type, the sediment settles to the bottom of the water side of the heat exchanger -right where the flames are- and the sediment acts as an insulator, retarding efficient heat exchange from fire to water at the bottom of the heat exchanger.

Triple pass heat exchangers may still get sediment settling to the bottom of the heat exchanger, but the injected flames still have the rest of the sides and top of the cylinder -and the entire inside of the cylinder- to exchange the heat from the flames to the water without sediment in between.

Which one is better? Better in what respect?

Joe_13

I wouldn't generalize like that

Biasi, Crown, Buderus are all cast iron. Biasi GG20 iron and I'm not sure what type of flex cast Buderus uses. These allow for cooler return water without shocking the boiler. The flex casting are smooth like teflon and easy to clean, less soot sticks to the fire chamber. I doubt most techs will take the time to clean a pin boiler properly. Ease of service is a big selling factor.

Unknown

I agree with all of that

However, we are talking about condensing, not shocking. Oil boilers condense with cool return temperatures. All of them, except those that have special return arangements that keep the internal temperature above condensing.

It's a law of nature, oil condenses below a certain return temperature. It is either meant to be a condensing boiler, or you need to pipe to prevent it from condensing. Can't be both.

Noel

Mad Dog

ok, I guess The Buderus reps brainwashed me at the last show

with all that good GERMAN BIER!!!!!! MD

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Radiant Wizard

I cannot believe

Radiant Wizard

I cannot believe

that nobody could actually give the differences between the two type of boilers.

Pin-Type Boiler - It's basically todays Burnham, Weil-McClain, Utica, Slant-Fin, Crown everyday boiler. It's 1950's technology. Fire a flame into a piece of cast iron, the btu's (heat) passes 1 time through a path of approx 1.5 sqft of heat exchanger (the sections of the boiler) surface area and out through the chimnney. They generally have only 3/4" jacket insultation and there stack temps (the temp leaving the boiler through the chimmney is approx 425 degrees. They also have to maintain at a minimum 140 degree water temp coming back to the boiler to prevent "boiler shocking."

3-Pass Boiler - This is a Buderus, Biasi, Viessmann Vitorond, DeDeitrich, Crown Freeport, etc. The burner is again fired into a piece of cast iron except that it makes 3 passes through the heat exchanger (approx 7 sqft) allowing the boiler to capture more btu's than in a pin-typed boier. It's stack temp run approx 325 degrees. They also have aprrox 4 inches of insulation around the jacket allowing less jacket loss. With this boiler you utilize more of the boilers gross btu's than in a pin-typed boiler. This boiler also allows for a much lower return water temp than that of a pin-type boiler allowing for a better outdoor reset (cruise control for you boiler) curve than the pin-type boiler.

The 3-pass boiler is a better boiler.

Unknown

Try the boiler I mentioned.

You will see the numbers are better than you assume. I'm not berating high effeciency boilers of any kind. I'd hate to see this much effort in a new pin type boiler be lumped with all of the rest, including ours.

It isn't the type that makes one better, it's the details, like the ones that you point out.

Noel

Radiant Wizard

They are not

good heat grabers. They are good Btu wasters. They tend to weight more than 3-Passs Boilers, heat up slower and cool down quicker due to jacket loss.

Steve Ebels

All other things being equal

I would much rather clean a 3-pass with a swing out door any day of the week and twice on Sunday. There is truly no comparison in that department.

We just installed a Buderus G215-7 and once again I was thrilled to see what it did performance wise. Flue temp below 380* at any water temp. Minimum efficiency of 86.6%. Zero smoke. High 4% O2 and CO2 in the high 12% range. CO under 10 ppm. Riello F-10 burner. They just flat out work.

Mad Dog

I implied the same thing wiz, the 3-pass is generally

a superior design.....much easier to clean. Pin-type may be on the way out and antiquated, but they have been a great workhorse for a very long time. There is always something better out there and inovations on the horizon, but some changes are very gradual. The vast majority of the general public are very stubborn and are not willing to spend a few more bucks for higher efficiency stuff. The folks who visit the Wall here, are the exception, not the rule. It can be frustrating, I Know. Mad Dog

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