Munchkin Boiler Size ? 80MR2 or 144MR2 ?
Thanks to those who responded to my initial post. From your suggestions I have decided to get a high effiency boiler. In what I have read and what has been suggested I've concluded Munchkin is a good choice of boiler. I have spoken to two well qualified plumbing and heating contractors however they don't agree on the size of the boiler and the size hot water tank and I need some help.
My home is a two story 4 bedroom colonial with 820 square feet on each floor and a portion of the basement is heated for a total of (820 x 2 + 260)= 1900 square feet of heated living area. The walls have R-13 insulation and the attic has R-45. (I don't know whether just this information is sufficient for a calculation. Is there a way I can calculate this somehow to determine the boiler size ?)
The current boiler is the original one - American Standard GPM 6; 38 yrs. old - Input: 165,000 Output: 132,000. The heating capacity to heat the home is fine.
Last month an energy audit gave the boiler a 78.5% efficiency.
My questions are:
1.Which boiler is sufficent ? 80M or 140M ?
(80M Munchkin data shows Input Modulation 27,000 to 80,000 and DOE Heating 25,000 to 74,000)
(140M Munchkin data shows Input Modulation 46,000 to 140,000 and DOE Heating 43,000 to 129,000)
2. What size Superstor hot water tank do I need ? SSU-30 or SSU 45 ?
With 4 bedrooms, one contractor suggests a SuperStor(SSU-30) hot water tank is sufficient. I think I need a SSU-45 with 5 in the family.
Thanks again in advance for your comments. I really appreciate the time and effort of those that respond to make us homeowners more informed.
I just replaced a old oil boiler (approx. 150,000 BTU) with the Munchkin 80 (nat. gas). My house is about the same size house as yours (actually approx. 2300sf) and it is more than enough. (a Heat Loss calc. was performed). These units are sweet. Saves space, run quiet, and most of all $$$.
I put a 45 Gal. Superstore with it. I am pretty sure the 80 will be fine. If you are that concerned, have a heat loss calc. done. Put one in and you'll love it!
Clickon the HVAC CALC link, pay teh fee and do your own load, since the plumbers won't do one for you.
With 5 people in the family, the 45.
The 80 would be on DHW priority too long with the 30 during high HW demans.
Your supplier of the mod-con and other hvac equip. can do the heat loss real quick. They are anxious to move the high effy. equip. (Mod-Con) and are able to do a heat loss calc. (10 minutes?) to earn your business.
The tough part is finding a pro who knows the equipment and has put several in. Keep looking, talk to manufacturers/suppliers of mod-cons. and you'll find the solution. Good luck.
More then 10 minutes to do it right.