Hi -

We are enjoying our first winter in our new house (built 1937) in St. Paul, MN. The Weil Mclain gravity boiler was installed in, I believe, 1973. As far as I can tell, it is working fine. A few questions:

1. What kind of lifespan is expected for such a boiler? Am I looking at replacing it imminently, or could it last a decade or more from now?

2. There is label that specifies input of 105,000 Btu/hr, output 84,000 Btu/hr. So - unless I'm missing something - it was rated as being 80% efficient when it was new. Is this efficiency likely to have degraded much over time? If so, can you guess what it is now?

3. I'm more familiar with forced air heat, and know about the benefits of modulating furnaces... same story with modulating boilers, or are the advantages not as great?

Straying away from my main question - the house is interesting, I have a boiler for first floor heat and the upper level (i.e., the top 1/2 story of what we call a 1 & 1/2 story style home here) is heated by forced air, and cooled by the same ductwork/fan. Unfortunately, the 1993-installed 60k Btu/hr 80% efficient furnace is rather loud, and way oversized - last night, at ~0*F, it was burning gas for only ~7 minutes per hour. I would like to replace it with something that outputs much less, with a slower, quieter fan. Any suggestions? What's the lowest output gas furnace there is? One of the modulating ones on the lowest fire?

Justifying replacing the furnace will be purely from a comfort point of view - from a consumption point of view, the boiler is doing all the heavy lifting for the house, and the furnace is just "topping off" the heat upstairs so we don't catch a chill in our beds.

Of course, either the boiler or the furnace may die, in which case my hand will be forced!

Thanks in advance for any info/advice you can offer!

Paul

P.S. I work for that large MN-based multi-national that makes, among other things, furnace filters...