Mich. Admin. Code R. 408.4278 - Relief valves
Rule 278.
(1)
Each hot water heater boiler shall have at least 1 officially rated pressure
relief valve set to relieve at or below the maximum allowable working pressure
of the boiler.
(2) Each hot water
supply boiler shall have at least 1 officially rated safety relief valve or at
least 1 officially rated pressure-temperature relief valve of the
automatic-reseating type set to relieve at or below the maximum allowable
working pressure of the boiler.
(3)
When more than 1 relief valve is used on either hot water heating or hot water
supply boilers, the additional valve or valves shall be officially rated and
may be set within a range not to exceed 6 psi above the maximum allowable
working pressure of the boiler up to and including 60 psi and 10% for those
having a maximum allowable working pressure exceeding 60 psi.
(4) Relief valves shall be spring loaded
without disk guides on the pressure side of the valve.
(5) Relief valves shall be so arranged that
they cannot be reset to relieve at a higher pressure than the maximum permitted
by this rule.
Notes
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No prior version found.