Wash. Admin. Code § 51-11C-40346

Current through Register Vol. 24-17, September 1, 2024

Section 51-11C-40346 - Section C403.4.6-Variable flow controls

C403.4.6Variable flow controls. Individual pumps required by this code to have variable speed control shall be controlled in one of the following manners:

1. For systems having a combined pump motor horsepower less than or equal to 20 hp (15 kW) and without direct digital control of individual coils, pump speed shall be a function of either:

1.1. Required differential pressure; or

1.2. Reset directly based on zone hydronic demand, or other zone load indicators; or

1.3. Reset directly based on pump power and pump differential pressure; or

1.4. Reset directly by an integral controller based on the relationship between variable speed controller frequency and power.

2. For systems having a combined pump motor horsepower that exceeds 20 hp (15 kW) or smaller systems with direct digital control, pump speed shall be a function of either:

2.1. The static pressure set point as reset based on the valve requiring the most pressure; or

2.2. Directly controlled based on zone hydronic demand; or

2.3.Reset directly by an integral controller based on the relationship between variable speed controller frequency and power.

Wash. Admin. Code § 51-11C-40346

Reserved by WSR 16-03-072, Filed 1/19/2016, effective 7/1/2016

Amended by WSR 19-24-040, Filed 11/26/2019, effective 7/1/2020

Amended by WSR 20-21-080, Filed 10/19/2020, effective 2/1/2021

Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. 13-04-056, § 51-11C-40346, filed 2/1/13, effective 7/1/13.