Cartridge assembly for a thermally responsive by-pass valve

A by-pass valve comprising:

• a valve housing defining a first fluid inlet, a second fluid inlet, a fluid outlet and an opening for receiving a cartridge assembly;
• and
• a cartridge assembly including a casing defining a first fluid port and a second fluid port;
• a thermostatic element containing a thermally responsive material, and having a piston movable in response to heating and expansion of the thermally responsive material;
• a cap joined to the casing;
• a biasing member compressed between the cap and the thermostatic element, the biasing member urging an end of the piston against a roof of the casing;
• a sleeve carried by the thermostatic element, the sleeve having a side wall that seats against first surfaces of the casing to block fluid flow through the first port when the thermally responsive material is at a first temperature, and that seats against second surfaces of the casing to block fluid flow through the second port when the thermally responsive material is at a second temperature greater than the first temperature.