I posted awhile back about boilers. I'm still trying to make up my mind. I am hearing a lot about 3 pass boilers. They are slightly more efficient and are said to stay that way b/c they are easier to clean. Are they really a lot better than conventional cast iron boilers? How long have US manufacturers been making them? Is it really that hard to keep a conventional boiler clean if you service it regularly or is this a marketing thing? System 2000 also goes on about how hard conventional boilers are to keep efficient.
Any thoughts? Thanks.