RM7838B, RM7838C 7800 SERIES RELAY MODULES
27 32-00211—01
Table 14. Schedule 40 Pipe Internal Cross-Sectional
Area.
Table 15. VPS Worksheet.
a
Divide inches w.c. by 27.7 to get psi.
b
Divide Btuh by 1000 to get cf/hr for natural gas or by 2550 to get cf/hr for LP gas.
SAFETY AND SECURITY
Physical device protection
Device shall be accessible to authorized personnel only –
Installation on publicly accessible places is not
recommended as this could lead to unwanted and
potentially unsafe changes to device (wiring,
configuration, etc).
It is recommended to lock the device in an enclosed
cabinet with access allowed only to approved and trained
personnel. Also, it is strongly advised to keep all the wiring
of device physically secure.
Physical protection of the device is applied via Run/Test
switch label/seal. It is intended to prevent and detect
unauthorized access.
Modbus & DDL Interface security
Any conducts critical to device functionality (DDL,
Modbus lines etc.) shall be physically protected (installed
outside public access) since they could be damaged or
tampered-with by unauthorized people, either
accidentally or for purpose.
Modbus RS-485 & DDL protocols do not support security
features. For DDL interface - only DDL devices shall be
connected to the Burner Controller DDL line.
License agreement
Copying and reverse engineering is prohibited by the law.
Pipe Size NPT (Inches)
Cross-Sectional Area (Sq.
In.) “A”
3/8 0.191
1/2 0.304
3/4 0.533
10.864
1-1/4 1.498
1-1/2 2.036
23.356
2-1/2 4.788
37.393
4 12.730
Pipe Size NPT (Inches)
Cross-Sectional Area (Sq.
In.) “A”
Item Description Information Lookup Table Results Formula Item
V1 Upstream Valve Volume 12 V1
V2 Downstream Valve Volume 13 V2
D Pipe Size NPT (in.) 14 A
LPipe Length (ft) — L
P
Valve Inlet Pressure (psig)
a
—P
C
Burner Maximum Firing (cf/hr)
b
—C