I have a Trane RTU Mod. TCD420AE0R2A7FE5AB0D0F0HJ000000 Ser. C05E04734 The Economizer Module Number is MOD02067, it has a RTRM Setting on it that the old Module doesn't have. I figured out it uses the bottom setting as the RTRM is a V 5.1 2005 HO. I do not know whether to set the Pot in the 500 or 1500/2000 direction??? Thanks