Section 341.47. Multi-boiler installations.

  When hot-water heating boilers are installed in multiples with a common header and a common return, isolation valves may be eliminated between units and the units may be considered as one boiler provided all of the following conditions are met:

(1)   Output limit. No single unit exceeds 500,000 Btu per hour output.

(2)   Pressure relief. Each unit has a pressure relief device as required by the ASME code, or the common header has a pressure relief device with sufficient relieving capacity for all units in the installation.

(3)   Controls. Each unit has operating controls and safety controls acceptable to the department.

(4)   Low-water cutoff. The fuel supply to each unit is shut off by a low-water cutoff in the event of low water in the system.

Cr. Register, February, 1988, No. 386 , eff. 3-1-88; CR 11-047 : am. (intro.), (1) to (3) Register May 2012 No. 677 , eff. 6-1-12.