Interpretation #7761

Published May 20, 2016

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Original Request

Code Version
2014
Code
MECHANIC
Code Description
Chapter
Section
307.2.3 #4
Topic
Water level detection device location

Question

Is it the intent of section 307.2.3 #4 to allow an approved water level detection device conforming to UL 508 be installed that will shut off the equipment served in the event that the primary drain is blocked in the primary drain line or the overflow drain line or the equipment supplied drain pan, located at a point higher than the primary drain line connection and below the overflow rim of such pan.

Answer Published 05/20/2016 at 8:37 AM

Yes. Please see the attached commentary.

Commentary

The specified device location of item #4 applies only to the equipment supplied drain pan and refers to it as "such pan". "equipment-supplied drain pan, located at a point higher than the primary drain line connection and below the overflow rim of such pan" It is not impossible or implausible that the device be installed in the sloped primary drain line but above the "outlet". If there were a blockage at the sloped primary drain outlet the resulting rising water column upstream would activate an in-line float switch.