I hear ya whistlenut , Talk about being blindsided. The LAST thing I would have thought to calculate into the heat load is a walk in bubble bath massage tub. The boiler up-grade thought crossed my mind. But, the little Kaa-2 does such a nice job of heating the house, I hate the thoughts (and expense) of tearing everything apart to replace it. My cheapest route to this low hot water capacity problem is to buy another electric hot water tank. One common thought everyone seems to have is not to do away with the electric hot water tank.whistlenut wrote:Another thought is that an 80 gallon tank takes up some room vertically, and a 40 or 50 or 60 gal tank would be easier to deal with. When you speak of the boiler not being able to maintain 180, who cares. If it would only keep the boiler at 150, who cares. Unless you are extremely close to design limit you will be fine. An indirect would be the ticket, however don't overlook a K-6 upgrade for long term benefits. This reinforces the assumption that bigger is better for unknown future requirements. The new electric tanks are extremely efficient and not too costly.
Look around on C-list or local papers for someone selling a 40 gallon indirect. I found a 53 gallon Buderus , three years old, for $300 this week. 1600 new.......the home had a new solar 120 gallon special tank installed, and I got it from the solar company. 1" feeds and returns, and 1" boiler feed and return. S KAA 2 would not like that flow requirement, but you could go with 3/4".
By the way, the solar tank was 5500.00, so before you jump off the solar cliff remember that was just the TANK, not the collector panels, piping, and installation. 18,000 more........but a 30% tax credit.......WTF. That was not the end of the story however........a new $32,500 auto feed pellet boiler , 6 ton hopper.......auto ash removal////all the toys.
The solar would make up 60% of the hot water needs for the year, so the original Propane Condensing Boiler will be a Primary/Secondary with the new Froling Pellet Boiler.
I asked to see the install because this is a top of the line system at over 60K, turnkey. I was certainly impressed with the logic, workmanship and the design intent....but sticker shocked at the investment. Makes upsizing the KAA seem like child's play.