Originally Posted by Viva
34 to 17 is a massive difference in db!
Exactly......it's huge. The new fan is barely audible (the compressor is barely audible as well). There are probably cost constraints on the factory fans, the replacement I purchased was $17.
At a high level, as the CFM goes down the condenser temp will rise, leaving less deltaT for the coolant cycle. Since the thing cycles on and off, there is margin for cooling capacity, so I imagine that as long as it's cycling the deltaT is where it belongs.
The Samba thread has some very interesting observations done semi-scientifically (Measuring on-off times and interior temps) Another interesting point from the Samba thread is that the amp draw of the factory and replacement fans is considerably less than the specs once up and spinning.
I would expect that with a lower CFM fan, the max ambient temp where the duty cycle is 100% would be lower.
It appears that all three sizes of the Truckfridge use exactly the same compressors, evaporators, condensers, etc. I would assume that the larger units will have a higher duty cycle than the smaller ones, since TINSTAAFL.