Mich. Admin. Code R. 408.4240 - Water column connections
Rule 240. No outlet connections (except for damper regulator, feedwater regulator, low-water fuel cut-out, drains, steam gauges, pressure controls or such apparatus that does not permit the escape of an appreciable amount of steam or water therefrom) shall be placed on the piping that connects the water column to the boiler. The water column shall be provided with a valved drain of at least 3/4 inches pipe size, the drain to be piped to a safe location.
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