boiler replacement

Jake2010

After reviewing many posts on the heating help wall and asking several of my own questions I plan to finally replace my oil boiler.  I would like to get some last thoughts on the system I have decided upon, and ask 1 or 2 remaining questions.  I am replacing an older American Standard boiler (45 years)  that is way to big for my house. House is 2000sf in central CT, heat loss aprox 50,000btu, 2 heating zones, total 118ft finned baseboard,  40 gal. Weil Mclain indirect, 2adults, 3 children, 2 showers, 1.5 gpm head in the kids bathroom (they don't know it) 2.5 in mine.

I plan to go with Burnham MPO 84 with the ODR and DHW priority controls, mixing valve on indirect to bring up temp and mix down, and I will line the chimeny with a SS liner. A few contractors have told me to go with the MPO 115, but they have not really done a heat loss.

My questions are,

1)  Does this sound like a good way to go, or am I going to be undersized?

2) What is the best way to go, cirulators for each zone, 1 circulator for the heating zones and a seperate one for the indirect, or 1 cirulator for all three and zone valves? 

3) What size piping to the indirect 3/4 or 1in, and what speed circulator would be correct for the indirect/  Would a 007 be ok?

Thanks for any recommendations you can provide.

 

Zman

Replacement

I would say you are good with the 84. It will easily meet you loss number and  you only have about 70,000 btu of radiation. A bigger boiler cannot deliver more heat to your house, as you are maxed out on radiation.

As for domestic water. It looks like the 84 will produce about 2.4 gpm "on demand". The 40 gallon indirect will provide a storage buffer for when you have more demand. If you feel you need more hot water, I would go with a bigger tank rather than boiler.



Your question on zone valves vs. pumps is a bit of a "Ford or Chevy" question. I your case I don't have a strong opinion.



I would select an indirect that has a good transfer rate and is not prone to calcification. Chances are it will have a 1" connection. I would lean away from serpentine style exchangers like the Amtrol boiler mate and towards models like the heat flo with an oversized coil. The circulator size should be based on the product selected.



Carl

Crunch

tk03

at http://www.hvac-answers.net/ may have some good feedback for you.



Crunch

Jake2010

Boiler sizing

Thanks for the responses, are there anyothers that would like to weigh in?