BOILER SYSTEM - COST FOR REPLACEMENT?

[Cindy Mastin]

I have never had to replace a boiler system. Per a plumbing contractor who was at the rental property to replace a leaking boiler valve, he stated that his fear in replacing the valve is needing to shut the system down. Since we don't believe the system has been serviced in years....if ever, he doesn't think it will fire back up. Can any boiler experts out there give me an estimate as to how much a new system may end up costing if it does in fact need to be replaced? It is a 2bd/1ba on a crawl (800sf). TIA!