But would a towtruck do the job? Just back up over the entrace and drop the tow cable directly downwards.
Attach it to the boiler, then winch it out.
Mate, that's what we call a wrecker over here. Don't know why.

Back when i was doing boiler installations we sometimes used a wrecker. All we had to do was open the bulkhead door, remove the stairs, and lower the boiler into the basement.