Wash. Admin. Code § 51-11C-40346 - Section C403.4.6-Variable flow controls
C403.4.6
Variable 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.
Notes
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.
State regulations are updated quarterly; we currently have two versions available. Below is a comparison between our most recent version and the prior quarterly release. More comparison features will be added as we have more versions to compare.
C403.4.6 Variable 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.
Notes
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.