Will 5-Section Boiler Be Too Big for 2300 Sq Ft Home ?rs-home-heating-steam-hot-water-systems/516413

pickncrew

My 28 year old Weil-Mclain P-366HE boiler is shot...seals gone and leaking. We heat with wood pellet & use GeoSpring hybrid electric hot water heater in our 2-story 2300 sq foot colonial in CT built in 1986. We still need a backup source and we may not always heat will pellet so it is time to replace the boiler. Not wanting to spend much and being a do-it-yourselfer, I have my eye on a used Buderus G115 /5 section oil-fired unit for the replacement. It came out of a home similar to mine with 2 zones plus an indirect water heater and is about 5-years old for $600.



From what I am reading a larger 5-section may be too big and inefficient and could lead to short-cycling on & off frequently. I believe the 5-section is rated at 120k BTU p/hr. I think I know the answer... do the heat loss calculator to right-size a boiler. I downloaded the Slant Fin program and started it but don't think I am going to spend hours doing it. I think I will pay $75 for a professional to do it.



So, based on experiences from those reading this thread... do you suspect a 5-section boiler will be overkill in my case and should I stay with a 3 or 4-section? My top pick is Buderus but realize there are other good products out there. Thank you for your replies...

Aaron_in_Maine

Too big

I would bet a 3 section Buderus would heat your house just fine. But a proper heat loss should be done. The 5 section is way too big.

icesailor

Lots of things:

There are lots of things you should so. Heat loss, measure radiation etc.



We don't discuss price here.



Mty take is that if you get that boiler and burner for $600.00 and it is in good shape and running when it was removed, you'd be stepping over a ten dollar bill to find the dime someone might have dropped. In your lifetime, you will never pay back a new boiler by the few pennies you save over buying the $600.00 Buderus and installing it yourself. Does it come with a Reillo burner? A plus is that you can easily switch that boiler to LP Gas.

If it was me, and I needed a new boiler, and I got a nice boiler like that one, and my wife was warm. and we saved all that money over e new one, she'd be happy. And she might take me out to diner with the savings. A lot more than you have saved with that 368 POJ.



IMO.

pickncrew

Good Points

The used G115/5 was in good running condition when it was removed as my understanding. Home was converted to gas before it was being rented out... not sure why they did not convert this one; maybe they realized it was oversize. It does have a Riello burner and Aquastat controller. Ice you bring up good points and I need to decide if I want to cheap out or spend $$$. Seeing how the roof and windows need replacing I am leaning towards getting something less expensive for right now. I can use existing circulators and Amtrol indirect. I think I would also install the Logamatic 2107 with external reset if I did get this 5-section.

icesailor

You misunderstood?

Did you misunderstand what I suggested?

I was suggesting that if you get the Buderus, as you describe, it is a really good deal and one that you will not find often. Your Weil-Mclain 68 series is shot and a new boiler of any brand is a lot more costly that the used boiler. It is also (as I understand it) compatible with a gas conversion burner like  Carlin EZ-Gas.

Even if you have to hire someone to go pick it up, have them put it in the cellar at the same time and install it when you get the time. A really good deal like that doesn't come up often.

There are a lot of really good oil boilers out there being thrown away in the rush to buy a stainless steel or aluminum beer cooler that will be parked beside the curb in 5 to 10 years.

Pipe then properly with a hydraulic separator as Primary/Secondary and the old house on the secondary, and if you want to switch to the beer cooler, just connect it to the primary side and you're good to go. Careful planning and planning ahead. An old Arcoliner or JO-JOT, No. Something modern with triple pass of tight pins (I happen to think that "Pinners" work fine. For my reasons.



But that's just my opinion.

pickncrew

Going to pass on the Buderus 5-Section

I decided to pass on the 5-section… do not want to regret being oversize down the road. I will go with a 3-pass, 3-section cast iron boiler and it may very will be a Buderus. If I can find a nice used one at the right price fine, I will reuse and save money or I might possibly buy new online and install myself and still save money. All I know is I cannot afford a turn-key system installed by a professional, like my oil serviceman just quoted me on. I can do all the work and hire a heating consultant if needed for design and startup.

icesailor

Boilers passing like ships in the night:

A Weil-McLain 366/368 HE boiler has a firing rate of .95 gallons per hour.

A Buderus G115-5 has a firing rate of 1.00 GPH.

It isn't how many sections a boiler has compared to another boiler, it is what it is rated to do and the testing done to determine that. Those two boilers are essentially the same boiler. a turn of the pressure regulator on the fuel pump will give you .05 GPH.  I hope that you tell anyone and every one where this good deal on a boiler is because someone will scoop it up in a moment. I wish I could have run into a deal like that when I was building a new house for myself.

Where is this boiler? Someone here might like to scoop it and use it. It will run on gas I believe. The Weil-McLain won't even if it was brand new.

SWEI

Just curious

Can you fire the 5-section at a lower rate with the proper nozzle pattern?  Greater HX area should increase efficiency slightly if it all works out. 

pickncrew

Located in...

The used G115/5 is in Bristol CT, search Hartford Craigslist. Yes that one will run on gas. One thing that bothers me is that it is sitting outside in 0 degree weather and although he said he drained the system when it was removed and also drained the boiler I have to wonder if there is any frozen water left in it. A 5-section is more than what I need.

icesailor

drained:

You mean like all the houses I drained the water in for the winter that had boilers? I never had one crack and break. Unless the boiler is full to the top, the expanding water will have a place to go.

How did you figure out that the Buderus is too big for your house when you are replacing a boiler that worked for you for 30 years with no complaints?

You can down fire the Buderus a lot easier than you can the 366. The more you down fire a boiler, the harder it is to keep a efficient and quality flame.

I guess you've convinced yourself that you don't want that boiler, even if it was given to you.

pickncrew

Guess so

G115/5 gross 136k btu/hr would certainly work but it is oversize and would use more fuel than a smaller unit. I probably should have a 4-section seeing how the old Weil 366 is rated for 109k gross. Spending that much on something used with no recourse if something were wrong with it does bother me to a degree.

icesailor

Ratings:

You're comparing apples and oranges. The 366 used a different way of rating. I always go by the IBR rating. That is the equalizer because no matter what you connect to, a 15% allowance for piping and pick-up used like a constant to make equal comparisons. There was no DOE rating on a 366 but is used for the Buderus. IBR is used for both. I've always used the IBR rating on each and every heating system I ever installed. I never once had a problem.

Understand please, I don't care a bit what you do. I only do this to inform myself through research about something I didn't know (the ratings between the two boilers) and to keep my aged, ADD ravaged brain active and unhealthy. And maybe someone reading what I have to say might learn some tid bit of useful information to them.

The higher you climb up the information/educational ladder you go, the harder it becomes to find the Pearls.

Buderus Ratings

http://www.buderus.us/files/201212071730550.G115WS_InstallationServiceInstructions_en_102012-6720804872.pdf

366 Weil-McLain Ratings.

http://www.weil-mclain.com/en/multimedia-library/pdf/weil-mclain-pdf/products/discontinued/discontinued-boilers/66-boiler/66manual.pdf

pickncrew

Net IBR

Ice - thank you, I am learning a lot. My old Weil 366 net IBR of 94.8k matches the Buderus G115/4 WS with 95k net IBR.

icesailor

Short Bus Math:

Short Bus math asks my ADD brain,  for $600.00, I can get a used boiler that is ever so slightly larger than the perfect boiler that I can buy for thousands of dollars more. How long will that theoretical difference in operating cost save me and how long (if I live that long) will it pay for the additional expense to savings?

I'm constantly reminded of this oddity now living in Florida where the average driver makes Boston and New York drivers look like the proverbial Little Old Lady from Pasadena, CA. I have a 2001 BMW 325XI wagon that will blow the doors off most cars around from a standing stop. It has a fuel meter on the s=dash that is part of the on-board computer system. I drive carefully and get greater gas mileage than the sticker when new. I do not practice Hollywood Boulevard, 1962 green light starts. Yet, almost every Florida driver is practicing for 10 second 1/4 mile runs. To the next stop light. How much do they spend in their gas sipping cars?

dav

I know this is an old post but unfortunately all of you overlook the fact that a btu is a btu. So many btu's are required to heat a house. There are things that can be done to make a short cycling boiler run longer. With controls. I do not recommend down firing a boiler. It is not efficient to do that. I prefer to widen the hi/low differentials to avoid short cycling. There are also many other things that can be done. Also, a buffer tank is a huge benefit in an oversized boiler. Further, I am not totally convinced that that much efficiency is lost in short cycling an oil burner.
Dave

EBEBRATT-Ed

@icesailor

I agree I don't think the "pinner's" are that bad either. People don't like to clean them. If set up properly and serviced cleaning isn't a big deal.

It's the stack temp that matters more than anything to keep the efficiency up. If you can get 83ish% what's wrong with that?

Give me a pinner slightly downfired and I am happy

What about the Bigger boilers, Smith 28s and Weil 86s. They are pinners and have been around for 45 years or so

mattmia2

getting back to the original question which was probably resolved one way or another years ago, if they want a project and the gaskets are leaking, why not disassemble and see if the gasket surfaces are ok, then reassemble with new gaskets if they are...

Ctoilman

I'd install the Buderus in a flash.  The short cycling efficiency loss is hardly anything to be concerned with....way over exaggerated comment. Any competent burner tech could downfire the unit some, as long as steady state flue temps stay above 250F.  Think more about the Logomatic reset control, that I sure would NOT install.