# Conversion of C-values into Vn values - Basic Documentation - GDB181.1E/BA - GDB181.1EMBA - GLB181.1E/BA

## VAV Compact Controller BACnet MS/TP G..B181.1E/BA

Product Family
OpenAir
Product Group
Damper actuators
Content Language
English
Content Type
Technical Documentation > Basic Documentation
Product Version
Status
Valid
Date
2021-10-26
Document No
A6V10631864_en--_g
A6V10695831
Stock No.
S55499-D168
S55499-D169
S55499-D506
Product No.
GDB181.1E/BA
GDB181.1EMBA
GLB181.1E/BA
Access level
Internet
File Type
html

In case the C-value of a VAV box is known, it can be converted into a corresponding Vn value as both are linked by Δpnom.

${\dot{V}}_{\text{nom}} = C \bullet \sqrt{\mathrm{\Delta}p_{\text{nom}}}$ and $V_{n} = \sqrt{\frac{300\ \lbrack Pa\rbrack}{\mathrm{\Delta}p_{\text{nom}}\lbrack Pa\rbrack\ }}$ $\rightarrow V_{n} = C \bullet \frac{\sqrt{300\ \lbrack Pa\rbrack}}{{\dot{V}}_{\text{nom}}}$
$$V_{n} = C \bullet \frac{\sqrt{300\ \left\lbrack \text{Pa} \right\rbrack}}{{\dot{V}}_{\text{nom}}} = 57.2\frac{\left\lbrack \frac{m^{3}}{h} \right\rbrack}{\left\lbrack \sqrt{\text{Pa}} \right\rbrack} \bullet \frac{\sqrt{300\ \left\lbrack \text{Pa} \right\rbrack}}{900\ \left\lbrack \frac{m^{3}}{h} \right\rbrack} = 1.1$$