VES Andover Ltd Eagle Close Chandlers Ford Ind. Est Eastleigh Hampshire SO53 4NF
Tel: 08448 15 60 60 Fax: 02380 261204 E-mail: vesltd@ves.co.uk Web: www.ves.co.uk
ecovent
NRG
Air Handling Units
Installation, Operation and Maintenance Manual
13
Δ
p
w
Differential Pressure Pa
NRG766
NRG867
NRG969
q
v
Air Volume m³/s
Continued
This differential pressure compares the static pressure in front of the fan inlet ring with the static
pressure in the inlet ring of the narrowest point. The differential pressure between the static
pressures is related to the air volume via the energy conservation rate as per the graph below.
Simply read across from the pressure measurement to the appropriate fan curve and down to
calculate the resultant air volume.
For example: Measured differential pressure: 550Pa
Unit:
NRG766
Reading from graph: 1.0
Air Volume: 1.0m³/s
This measurement can also be expressed in the following calculation:
q
V
= (
k
p
W
) / 3600
where q
V
is the air volume in m³/s
k
is the fan nozzle coeffi cient ( NRG766 = 154, NRG867 = 197, NRG969 = 308)
p
W
is the measured differential pressure in Pa
For example: Measured differential pressure: 550Pa
Unit:
NRG766
q
V
= (154
550) / 3600
q
V
= (154 x 23.452) / 3600
q
V
= 3611 / 3600
q
V
= air volume = 1.003 m³/s
Differential Pressure
Commissioning Graph
Fig.
Standard Wiring
& Fan Installation
5
