ArdWrknTrk Posted Thursday at 12:22 PM Share Posted Thursday at 12:22 PM We're getting chilly evenings up here and now that I have a ball valve in one of my heater lines I find I can throttle it. This is working well until I figure out why my outside air door is not sealing (yes, vacuum does move the lever by the hinge) My brother has a fancy BMW but the fans make horrendous noise above about 2/3 speed. I've got no idea how a luxury can can get away with that. Link to comment Share on other sites More sharing options...
85lebaront2 Posted yesterday at 12:31 AM Author Share Posted yesterday at 12:31 AM Jim, you should have heard the heater fan in my 1961 220Sb, it roared on high, but still didn't move much air. They had an axial fan that sat in the center of the air inlet scoop and blew downward through the two heater cores where a pair of doors (one on each side) were used to direct it up fro defrost or down for heat. Link to comment Share on other sites More sharing options...
85lebaront2 Posted 23 hours ago Author Share Posted 23 hours ago On the Chrysler ATC systems, the FWD models had two different designs, the first was all vacuum controlled except for the blend door, which had a servo motor. They were built as a semi-automatic or full automatic system and had a power module with a power transistor for the fan and 5 single acting vacuum valves two relays, one for the high fan and one for the AC compressor clutch. The control head was the only major difference between semi and full auto systems. The air inlet door was an all or nothing style, either recir or fresh. The older systems had a 20% fresh/80% recirc position that was used in the AC mode as it came off max cooling to reduce the system shock of hot humid air but still providing ventilation. I am adding a bi-level function as the manual and semi auto units had and that the earlier AutoTemp and 1st version AutoTemp II had and Mercedes-Benz had on their early AutoTemp II clone. Since these pre-date the FMVSS requirement that loss of vacuum defaults to defrost. These used bi-directional vacuum actuators, where the newer sytems are single direction with a spring for the default action. Both the mode (panel, bi-level or floor) and the defrost (floor, mix or full defrost) have two nipples, one at the end away from the rod and the other on the side. The system has two defrost modes, lo and hi, lo is temperature blended and hi is full heat, high blower. On both of these (bi-level and low defrost I need a mid position on the doors so will use some solenoid valves to achieve this. Link to comment Share on other sites More sharing options...
Gary Lewis Posted 13 hours ago Share Posted 13 hours ago Quite the system, Bill. That will be very functional. Link to comment Share on other sites More sharing options...
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