Heater system

I'm in the process of trying to get the heating system for the house repaired, which is driving me insane. It would help if there was some kind of universal system to filters and parts and stuff. There was a time when I could rip things out and repair them on my own, but the stuff is all electrical and such now.

I got the thing off the heater downstairs, and I would be willing to have someone else work on it, but I can't even find someone that can look at the system now that I have removed it from the water heater. They all insist they have to come to the house and repair it here, which adds in a $125 to the bill just to have the least expensive of them come look the system over. If they need to work on it... the price goes up significantly and keeps going up.