Operating Instructions

Chapter 2 – Applications
Application 2926 LCM-OAVS Venturi Fast Speed, with BTU Compensation
12
Siemens Industry, Inc.
Owner's Manual, Apps 2920/2926
125-5109
2015-06-30
Application 2920 Control Drawing.
Application 2926 LCM-OAVS Venturi Fast Speed, with
BTU Compensation
The LCM is specifically designed to perform these functions in laboratories with VAV
fume hoods. This version of the LCM uses one supply duct with a reheat coil, one
exhaust duct and up to six fume hoods using an averaging and scaling module.
Pressurization is controlled by maintaining a selected difference between supply and
exhaust airflows and uses fast-acting electronic actuators (shipped separately) to
control the supply and exhaust Venturi air valves.
NOTE:
If desired, the LCM can be used without any fume hoods attached. In this case, MAX
HOOD VOL should be set to 0 cfm to disable the alarming that would occur if
MINHOODVOLTS is set to 1 Volt or more and the fume hood flow input drops below
.4 Vdc.
Pressurization is controlled by maintaining a selected difference between supply and
exhaust airflows.