Patent ID: 8205802

Claim:
A pre-assembled unit, comprising: an annular cap defining a valve seat; a thermostatic valve in the annular cap and including; a valve member received in the annular cap and mechanically biased by a valve spring to directly engage with the valve seat; the valve spring having one end resting directly against said valve member; and an expansible element surrounded by the valve spring; a mating rest element; and a U-shaped retention member received in the mating rest element and including a central strip directly sandwiched between the mating rest element and the other end of the valve spring, and legs extending from both sides of the central strip to the annular cap, wherein the annular cap further includes recesses, wherein each of the recesses is opposite to another recess, and each of the legs includes a hook element which outwardly extends toward the annular cap and is directly received in the respective recess.