Thermo regulator only cools the gas passing through it once, after that the temperature of the gas goes back to the previous temperature,
example: Gas at 25ºC goes goes inside, -14ºC, 11ºC gas appears.
gas comes back at 21ºC, leaves with 11ºC, (instead of 21 - 14 = 7ºC)
example in the save file.
Thermo Regulator on a closed loop, let it function, it won't work after the first go.