Need some Input for a new boiler system
Im a 2 month lurker making my 1st official technical post on the forum but have learned a great deal from the info here. Am planning a new boiler installation here in the next month or so. Have a ranch house with ~1800 sf heated space, 111 feet of 1/2" cu tube/Al fin baseboard, heat loss of the house is estimated at 55,000 BTU/hr. My current boiler is a wood/coal burning unit that was retrofitted for oil rated @ 143000, the tankless coil is plugged up and not used, and am using a 50 gal electric HW heater. There are 3 heating zones, 1/2" cu tube for supply & return piping, but the valves & manifold are 3/4" along with the boiler water return piping main, and 1 taco circ pump on the return side of the boiler. Have an intact clay lined chimney that is in the middle of the house. 4 people occupy the house.
Done lots of research and still am on equipment. As much as I like the Buderus G115, I don't like it's pricetag and am right now settling on the Biasi B10 w/ Riello although the Burnham MPO IQ was suggested to me as well.
So, here goes my questions:
1. is the Biasi B10-3 sufficient for the house & 40 gal indirect HW heater?
2. Is an indirect water heater really going to save money? Right now I pay $3.64/gal #2 fuel and $0.099 kw-hr. The fuel heating value & cost factor to $0.088 kw-hr. But it boils down to efficiency, right? Or is it something entirely different?
3. Going to try the new boiler without an outdoor temp reset for the 1st year, then maybe add it on. Does this feature really make a difference?
4. Circ Pumps - Grundfos Alpha or TACO circ, which do you guys prefer?
5. Indirect water heaters - coil heating bundle vs tank-in-tank design? again, which do you guys prefer?
Thanks in advance for the input. Gd night~
At your per gal oil cost, using 85% efficiency, oil would be the equivalent of .1043 cents per KWH. So an electric water heater will probably cost less to use then an indirect.
I'd get the outdoor reset right a way. It will save money on your oil bill.
Coil in boilers is very inefficient. I would be using the indirect tank with a new boiler. I've put in lots of Burnhams and they are Ok but the castings are an old design and the Biasi seems to have a newer design.
Big thing with oil.....don't oversize the boiler. Stick to the heat loss. The other thing is also to use a bigger indirect tank. 40gal may not be big enough for you because the heat exchangers are often a bit small but that depends on the manufacturer.
With oil or electric heat, i would seriously look at putting a solar water heater in. That way the boiler is not going to fire up during the summer months to do a small load like DHW often is. The savings are very good.
BTW, the Grundfos Alpha is a great pump.
Yah, just did some more math and at $0.01 savings, I'll never recoup my investment with an indirect heater. So I'll save those pennies for the solar heating system as per Mike.
Setting the course for the B10-3 Biasi and ODR. Otherwise, I will install a TACO and some extra piping from the farthest applicance for domestic hot water recriculation, figure I'll minimize HW waste and save a few bucks on the electric bill.
Gotta read up on the Grundfos
Thanks for the input, guys!
No worry dude, I dont know what your kwhr rate is, maybe $0.10 difference? I wouldn't sweat it, and an indirect will easily outlast an electric or fuel fired water heater.
If you are going to do a recirc pump, Grundfos has one with a nice little timer on it
Originally Posted by Kobe Diesel
A good indirect will last 2-3 times longer than the electric and give you much quicker recovery. The electric has about 15k btu/h input; the indirect has the full output of the boiler if piped and controlled correctly.
I almost always use a 32gal. indirect (unless the job requires larger) and I've never had a customer complain about a lack of hot water.
A rough rule of thumb: you'll get about 1gal. per min. recovery per 40k btu of input to the water heater. You also get about 80% of the tanks storage capacity, so a 40gal. tank will give you about 32gal. of hot water.
I would concur with SolarMike about not over-sizing the boiler but increasing the storage capacity of the tank.
If you're considering solar in the future, get a properly sized dual coil tank now and connect the solar to it when you get that. "Properly sized" meaning sized with enough buffer for the solar.
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BB - thanks for that insight, I will investigate further on it.
How about ODR's?
The Tekmar 256 is fairly popular but I also came about the Taco PC702-1. Side-by-side, these units are almost identical and seems so in function as well after reading the I/O manuls. Did Taco 'borrow' the Tekmar technology? Opinions and input are welcome!
Tekmar makes it for Taco. And yes, ODR can save you a lot $$. It will become mandatory next year or so.
Dual coil tanks are good if you want to use the solar option in the future, and you won't be disappointed if you do. Just remember that your effective volume without the solar is at the top of the tank so depending on the number of people in the house and boiler size 80 gal would be minimum. I like Viessmann tanks (the ceramic lined ones are a lot better value than the SS tanks) because the HX is quite generously sized.
When considering solar, my 25 years of installs says....stay away from the chinese tubes and use a good old flat collector which could be Viessmann or from a number of other local makers.
Looking at IBR and DOE capacity figures, so that I don't pick a boiler that is under/over sized.
The HW piping is in the basement (which is unheated but not cold during the winter). THe piping has foam tube insulation and none of it runs in cold or outdoor areas. Should I still go with IBR or DOE numbers?
IBR is a much better indication of what the boiler will put out then DOE as it also includes piping losses (to some extent)