Mich. Admin. Code R. 408.4286 - Relief valve connections

Rule 286.

(1) Relief valves shall be connected to the top of boilers, with the spindle vertical either directly to a tapped or flanged opening in the boiler, to a fitting connected to the boiler by a close nipple, to a Y-base, to a valveless water pipe between adjacent boilers, or to a valveless header connecting water outlets on the same boiler. When a Y-base is used the inlet area shall be not less than the combined outlet areas.
(2) When the size of the boiler requires a relief valve larger than 4 1/2 inches diameter, 2 or more valves having the required capacity shall be used. When 2 or more valves are used on a boiler, they may be single, directly attached, or mounted on a Y-base.


Mich. Admin. Code R. 408.4286
1979 AC

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