Hi, I am purchasing an older home. I am told the amps are still original and are 100 amps for the heating system (propane wall heaters). Can you please tell me how difficult would it be to change from 100 amps to a 200 amps? Also, attaching photos of current wall heater (there are 2 identical ones, one between master and 2nd bedroom, other in living area and kitchen in dividing wall on both) and the inside of the heater, what can you tell me about it? What should one do before firing it up? the house has been vacant for about 4 years. Thank you!