Interpretation #7370

Published July 19, 2014

Download Final PDF

Original Request

Code Version
2010
Code
MECHANIC
Code Description
Mechanical
Chapter
3
Section
307.2.3.1
Topic
Drain line monitor external to AHU

Question

Is it the intent of 307.2.3.1 which states "a water-level monitoring device shall be installed inside the primary drain pan", to permit installation externally in the drain line, if the a/c unit manufacturer design does not allow for a device to be installed internally?

Answer Published 07/19/2014 at 4:52 PM

No. Please refer to the attached commentary for explanation.

Commentary

The section in question is for down flow units or other equipment without a secondary drain outlet. As to this question, the code does not recognize a float switch in the primary line as meeting the secondary protection required. The allowance for the switch inside the primary pan allows the possibility that a blockage will occur at the outlet of the drain pan and the switch inside the pan would prevent an overflow.