§ 23.25.603.5.23. Hydronic heating/cooling.

Amend section 603.5 by adding a new section as follows:

603.5.23 Hydronic heating/cooling. Systems with heat transfer fluids containing plain water or water/propylene glycol mixture require a minimum double check valve with intermediate atmospheric vent backflow preventer to be installed on any directly connected potable water makeup piping to the system. (A suitable example of this backflow preventer is a Watts 9D or a Hersey BCP valve.) In addition, the below listed requirements shall be complied with when a system contains propylene glycol:

1.

Water/propylene mixture shall contain a food grade powder dye. (A suitable example is FD+C Powder Dye.) Liquid food coloring is not acceptable due to its potential dissipation into the system.

2.

A warning tag shall be installed on the backflow preventer stating the following information:

A.

System contains propylene glycol - use no other substitute.

B.

Do not add ethylene glycol or automotive anti-freeze of any type.

C.

No high hazard toxic chemicals permitted to be added to this system.

Systems with a heat transfer fluid containing Ethylene Glycol approved for such use require minimum protection of the potable water makeup system by installation of a physical air gap or a reduced pressure principal backflow preventer.

( AO No. 2015-127, § 1, 4-1-16 )