Hi,
I'm looking to replace my 40 something year old natural gas boiler with something a bit more efficient. House is heated with fin-tube baseboard. After watching all the video's on the Taco site, doing a degree day heat consumption analysis based on my actual usage, doing a room-by-room manual J load calculation, and measuring my baseboard / mapping the zones, here it is:
2500 sq ft, 2 story home, 2x4 walls with fiberglass bats, in Topsfield MA (5F design day temp)
Degree Day analysis = 45k BTUH
Room-by-Room Manual J = 58.5k BTUH
Zone 1: 13.5k BTUH, 41 linear feet of baseboard, 120 ft of pipe ~ 7.2 ft head
Zone 2: 15k BTUH, 42.5 linear feet of baseboard, 100 ft of pipe ~ 6 ft head
Zone 3: 8k BTUH, 53 linear feet of baseboard, 140 ft of pipe ~ 8.4 ft head
Zone 4: 22k BTUH, 102 linear feet of baseboard (1" start splits into 2 parallel 3/4" loops), 150 ft of pipe ~ 9 ft head
Zones 1 and 2 are both the main portion of the first floor, and their thermostats are always programmed the same... I could combine the two into a single zone, giving me:
Zone 1-2: 28.5k BTUH, 83.5 linear feet of baseboard, 150 ft of pipe ~ 9 ft head
Zone 3: 8k BTUH, 53 linear feet of baseboard, 140 ft of pipe ~ 8.4 ft head
Zone 4: 22k BTUH, 102 linear feet of baseboard, 150 ft of pipe ~ 9 ft head
Does my above degree day analysis / manual J room-by-room look ok?
Assuming I go with the higher number (58.5K BTUH), I'm trying to determine what boiler to go with (I plan on adding an indirect water heater to the boiler in addition to the above zones), and whether or not combing zones 1 and 2 would help.
Any advice is greatly appreciated.
Thanks,
Mark
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Comments
You have several zones , a couple which at lower outdoor temps will require some buffering . Take a look at this boiler and add the indirect whenever . You are falling into the same trap where many get hung up , having enough BTUs when you should be more concerned with the lower end . Making it big enough for all your future needs is a consideration , but not all that difficult . Take the time to look at this and remember it cannot be oversized . 4 sizes , 100 , 130 , 160 , 199
http://www.htproducts.com/pioneer.html
Remember that this gives you the mass to not shortcycle based on programming the Differential properly , has outdoor reset and you can kook up your indirect later . Just size the maximum you could expect to use for either space heating or DHW . Use the smallest Indirect you can while storing at 150 - 160 * using a mixing valve (ASSE 1017) . You can make a 40 perform like a 75 gallon and a 30 like a 50 gallon . Be smart .
Langans Plumbing & Heating LLC
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Serving most of New Jersey, Eastern Pa .
Consultation, Design & Installation anywhere
Rich McGrath 732-581-3833
Right now I am leaning toward a Viessmann 200 B2HA-19. It has a min fire of 10.9k BTUH, and a max of of 61K BTUH. Thoughts on the Viessmann?
If you go to fill a large tub (like a Jetted tub), never turn on the hot water wide open and fill it most of the way, then top it off with cold. The hot will run out. If on the other hand, you mix the water to a comfortable level and fill it with mixed water, you will fill the whole tub and have hot water left over. At least, that's how it works in real world experienced practice.
Increasing the water temperature in a particular sized water heater storage tank, increases the theoretical size. Due to the more usable hot water to mix with the cold in practical, real world application.
So I can keep the water in the indirect at say 150, but have it mixed down to 106. If it was a 50 gallon water heater with 150 degree water in it, I'd be able to fill a bathtub much larger than 50 gallons with water at 106 degrees.
Check Ebay today they have a dented indirect viessmann 80 gal. tank that ends in 5 hours. thought you might want to know. Their are two in the picture but you can't choose between them one looks better than the other.