A valve includes a first inline compartment to attach to a first return line exiting a processing chamber and a second inline compartment to attach to a second return line entering a coolant source. A flow compartment is attached between the first inline compartment and the second inline compartment and through which a coolant is to return to the coolant source. A first inlet orifice and a second inlet orifice positioned between the first inline compartment and the flow compartment. A plunger has a tip to variably open and close the second inlet orifice. A shape memory alloy (SMA) spring is positioned on the plunger and attached to the tip, the SMA spring to variably increase or decrease a flow rate of the coolant through the second inlet orifice according to a temperature of the coolant.