Originally Posted by liljoejoe54
I think he means if you have more than one rad in your loop, make sure both are setup the same way. Both of them are intakes or both of them are exhaust, dont put one rad as intake and one rad as exhaust. Im still not 100% sure if that matters though.
Radiators work on an air-water temperature difference. A good temperature difference is around 10C. Lets assume you have two identical radiators, with one configured as intake and one as exhaust. With a 10C water-air delta they can dissipate 500W of heat.
Radiator 1 gets 20C air intake, and with 30C water it has a 10C delta. This allows it to dissipate 500W of heat. The air exiting the radiator is 28C.
Radiator 2 gets 28C air intake, and with 30C water it has a 2C delta. This allows it to dissipate 100W (2/10 = 1/5 of 500W) of heat. The air exiting the second radiator is 29.6C.
As you can see, the first radiator heats the air by a large amount and makes the second radiator only able to dissipate 1/5 of the amount of heat. While the numbers change based on your scenario, the second radiator will always perform much worse.