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T-Cut · 21st November 2019, 13:08

As I see it, the 2-speed system switches to Speed 1 for the duties provided by 'low' and 'medium' speeds of the earlier system. Speed 1 appears to be faster than the earlier fan's 'low' speed and provides sufficient airflow for 'medium' speed duty. It could be argued that a 2-speed system 'overkills' the 'Low' speed fan duty. I recall that Arctic uploaded a video demonstrating T4 tests of a resistor controlled 2-speed. He trips Speed 1 when the T4 'Low' speed test is applied, then Speed 2 using the 'High' speed test. Unfortunately, he doesn't show T4 and the 'Medium' speed test on this fan. This will answer the question and I guess Arctic will know.

EDIT: I see Arctic's T4 tests were on an isolated fan not installed with an ECU, so perhaps the T4 would be invalid for the medium speed test?

TC

21st November 2019, 13:08	#66
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,753 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	As I see it, the 2-speed system switches to Speed 1 for the duties provided by 'low' and 'medium' speeds of the earlier system. Speed 1 appears to be faster than the earlier fan's 'low' speed and provides sufficient airflow for 'medium' speed duty. It could be argued that a 2-speed system 'overkills' the 'Low' speed fan duty. I recall that Arctic uploaded a video demonstrating T4 tests of a resistor controlled 2-speed. He trips Speed 1 when the T4 'Low' speed test is applied, then Speed 2 using the 'High' speed test. Unfortunately, he doesn't show T4 and the 'Medium' speed test on this fan. This will answer the question and I guess Arctic will know. EDIT: I see Arctic's T4 tests were on an isolated fan not installed with an ECU, so perhaps the T4 would be invalid for the medium speed test? TC Last edited by T-Cut; 21st November 2019 at 13:16..