The gas furnace for the clubhouse of our townhouse complex (near San Jose, CA) has decayed to the point where we have been advised to replace it immediately. Normally this would be a pretty straightforward replacement, but this furnace is housed in the pump room for our pool, which means the floor is often wet and there is concentrated chlorine, whose fumes tend to be rather corrosive to anything in that room. I'm looking for suggestions about anything we can do to lessen the damage or reliability impact from being in that environment.

The original furnace was installed in 1978, and worked well in large part because the design was so simple that very little could break. We're rather concerned that a newer furnace, with logic boards, extra sensors, etc. will be more prone to failure, and are looking for advice on what we can do to help avoid future problems. Space in that room is very limited, and there are no other practical locations for a furnace, so we don't have a lot of choice but to install the new one in the same location.

The climate here is rather mild, and the clubhouse only occupied for a few hours a month, so it's not often heated above 55 or so. Because of that, it doesn't seem cost effective to spend a lot on a super efficient furnace. However, we're willing to invest in quality if it will mean a longer life and/or reduced future maintenance expenses.

I've asked a few HVAC contractors for advice. We would need about 60K BTU. One suggests Trane XB80, and another Trane XR80. As I understand it, the major differences are insulation for the blower motor (which probably isn't a big deal) and more reliable igniters (which, if it means fewer service calls, may well be worthwhile). I see lots of gripes from owners about bad igniters, but given that happy owners rarely post to such forums, am having a hard time determining if that's really as serious a problem as the postings imply.

One contractor made the reasonable suggestion that raising the new furnace a few inches would help shield it from the wet floors. What else can we do to make the best of this unfortunate environment? There's no space to do much re physical isolation.

Are there any significant differences in design/construction between brands/models that would be relevant here? Where can I find detailed descrptions of these differences? I've been quite disappointed at how useless the marketing brochures are about providing detailed descriptions, and was surprised to not find owner's manuals, etc. readily available on the web, as most manufacturers seem to do today.

Given the very intermittent use of the clubhouse, and the mild climate, how critical are the load calculations? The original furnace was so generic (and now so decayed) that I can't find any real hints of what brand/model/size it was. There is no air conditioning involved.

Any words of wisdom about how best to proceed would be greatly appreciated. I'll gladly do detailed reading if someone can point me toward any applicable documents. Thanks!