Improvements relating to water heaters
876,383. Valves. SANTON Ltd. Jan. 21, 1960 [Jan. 21, 1959], No. 2188/59. Class 135. A water heater comprises an outlet tube 3 having one or more apertures around its periphery sealingly covered by a resilient sleeve 7, the sleeve, upon a predetermined increase in pressure being reached in the tube, expanding to release the excess pressure therein.