Heater core install and system flush

[ttikalsky]

The second propane furnace crapped out, lights but shuts down after
2-3 seconds. I believe it is the thermocoupler but there are 2 and
they are entirely different than the current style. Now I am down to a
single unit because they are old Dou-Therms and they haven't made
furnaces for 15+ years so I'm guessing the parts haven't been made for
a while.

I am installing the Proheat system in my rig and there are currently 2
heater cores, 1 under the rear queen and 1 under the front couch, not
counting the dash heater core. I am planning on adding at least 1
additional heater core and fans. I am planning on adding additional
fans to the current heater cores, the existing fans are automotive
fans and I think they will draw too many amps and drain the batteries
quickly. Someone suggested using old computer cooling fans I am
guessing because they have a low amp draw. Any suggestions on sources
for heater cores? Would a home baseboard heater work?

I also Recall someone mentioning using a sump pump to fill the heat
core coolant lines after a flush, anyone remember this... Randy?

Troy Tikalsky
1986 Newell 40'