I had a high efficiency gas fired Munchkin boiler installed about 8 years ago. It has been very problem prone and the brand is no longer manufactured. The condensate collection system cracked and began leaking the second heating system of use and had to be replaced. The natural gas mixing valve has been replaced two or three times. The plastic fan which brings in outside combustion air and eshausts the combustion gases has had to be replaced at least four times because the paper thin vanes get brittle and break off, creating turbulance in the heat exchanger. When it fires inside the house it makes a sound like a table being drug across a wood floor and outside near the exhaust vent it sounds like a low vibration fog horn. I had it replaced four weeks ago and it started making the noise after two weeks. Basically, it is a piece of junk and the serviceman says it is bad design.. Can you reccomend a reliable replacment boiler. The house was built in 1933 and had an Iron Fireman boiler which had been converted first to oil and then to gas and the only repairs it ever needed was to replace the hot water circulating pump electric motor. The only problem was that it was not very efficient.