Packard Forum Index » Post-War (1946-54)

I don't have any photos of a 54 underseat install but it is essentially the same as the 55-6. You can certainly do it the way you mention as the cores will still be in series just as they would be if the front heater connected to the HCV first. The only difference will be the underseat heater is getting the hottest water and by the time it gets to the front heater it will have cooled a little. The sensing element of the HCV gets a small amount of heated air directly blown over it from the front heater to sense what the heater is doing to better control the amount of water flow.

I don't think the valves are that sensitive under the best of conditions anyway but with the air on the sensing coil being slightly cooler it may affect the temp control a small amount but I doubt enough to get excited over..