Two-way temperature-regulating valve

turning the manual override wheel up or down. The use of the manual override inhibits the thermostatic assembly and should be used only when the thermo- static assembly is inoperable. Corrective maintenance of the regulating valve consists of inspecting the valve for leaks and for freedom of stem movement, adjust- ing the set point at which the valve regulates, renew- ing the thermostatic assembly, and cleaning and restoring valve parts. Any time that you remove a valve, you should center punch a dot code on each piece to ensure that the valve and the piping are installed in the original configuration. Individual maintenance manuals for temperature- ample, if you remove the top of the thermostatic assembly without chilling the temperature probe, the bellows will expand and rupture, making the unit worthless. To verify that the thermostatic assembly has failed, close the valves upstream and downstream of the thermostatic bulb, drain the unit below the loca- tion of the bulb, and remove the bulb from its well. Place the bulb in a suitable vessel and observe the valve stroke while the bulb is alternately heated with hot water and cooled with cold water. If the valve thermostatic assembly does not respond, it has lost its thermostatic charge, and anew unit must be installed. Figure 2-11 shows a two-way temperature-regu- regulating valves should be closely followed. For ex- lating valve. Figure 2-11.—Two-way temperature-regulating valve. 2-14