(1): according to UL approval

Evaporator pressure regulators, CLASSIC line

These are regulators designed to maintain a constant evaporating pressure and thereby a constant surface temperature on the evaporator under varying evaporator loads. This regulator prevents too low evaporating pressure and therefore protects the water chiller from freezing or the formation of ice in air evaporators.
Accessories for use with the following ASHRAE 34:2019 refrigerants, Class A1:
HCFC (R22)
HFC (R134a, R404A, R407C, R410A, R507)
HFO (R1234ze)
HFO + HFC (R448A, R449A, R450A, R452A, R513A, R515A, R515B)