A check valve, clack valve, non-return valve or one-way valve is a valve that normally allows fluid (liquid or gas) to flow through it in only one direction. Check valves are two-port valves, meaning they have two openings in the body, one for fluid to enter and the other for fluid to leave.
Some causes of cold intolerance are: 1  Anemia. 2  Anorexia nervosa. 3  Blood vessel problems, such as Raynaud phenomenon.  Chronic severe 1  illness. General poor health.  Underactive thyroid 1  (hypothyroidism) Problem with the hypothalamus (a part of the brain that controls many body functions, including body temperature)
If you find yourself constantly reaching for a sweater or blanket, it might not be the thermostatâs fault. Jacob Teitelbaum, M.D., author of Real Cause, Real Cure, tells Newsmax Health that certain health conditions, including thyroid problems, Raynaudâs disease, and iron deficiency can cause you to feel cold. The thyroid gland plays an important role in relation to whether the body feels cold.