I suppose it may end there but we're simply discussing the topic at this point.
I still say that unless something about the house was misrepresented by the seller and/or there were malicious omissions from the disclosure statement, the seller cannot be held liable. Of course this is just my opinion but there's a wealth of info to be found easily using yer favorite search engine....ya, bon jour
Seriously, as many crazy lawsuits as there are, if selling a house was this "dangerous", the whole process would be a far bigger nightmare than signing yer name 200 times and incurring decades of fun and easy to make payments.
To the OP- Def a mistep in eliminating part of the existing heating system. I'd simply call a few RE agents and pick their brain regarding your current situation. While you're certainly in the minority, I'm sure there are plenty of homes sold with similar heating setups. Exterior/interior wood/pellet furnaces..etc.
I think at worst, you devalued your property and made the pot of potential buyers very small but I don't think you've created an unsellable property. The property will have its assessed value to the bank, insurance company and town/state. If the value is there in the eyes of a bank, and the buyer is qualified, it'll sell. Insurance companies will insure most anything if you pay the price.