F-1031, Section 2119
Page 5 of 24
Unload / Fixed / Auto Control Switch
Once the compressor’s clutch is engaged, the Unload /
Fixed / Auto control switch allows the operator to select
between three air compressor pressure modes:
1. Unload (Standby) - The air compressor essen-
tially idles, producing a minimal pressure (40 PSI)
to maintain compressor oil flow. The compres-
sor’s clutch shall only be engaged when the Un-
load / Fixed / Auto switch is in the “Unload” posi-
tion and master air pressure gauge reads “0” PSI.
2. Fixed - air pressure is maintained at a preset pres-
sure setting (150 PSI).
3. Auto - air pressure matches water discharge pres-
sure.
NOTE: For an explanation of Control Air Circuit func-
tion during each operation mode, see Page 16.
Hose Pressure Hazard.
May cause serious personal injury.
Use only fire hose that is rated at 200 PSI or higher
working pressure.
CAFS Nozzle / Flow Rate / Hose Com-
binations
Nozzles
Compressed air foam can be discharged through various
types and sizes of nozzles. Fog nozzles break-down the
bubble structure of the foam, resulting in a “wetter” or re-
duced expansion foam. Similarly, when utilizing smooth
bore nozzles with a given hose diameter, smaller tips will
discharge “wetter” foam.
Foam Concentrate Ratios
Proportioner settings of 0.2% and 0.3% are typically ade-
quate to produce compressed air foam that is formed in a
hoseline and used on Class A combustibles. Higher set-
tings will result in a “drier” appearing foam. Lower settings
may result in “slug flow” or discharge pulsation caused by
insufficient foam concentrate in the solution to form foam
in the hoseline.
For Class B or other type foam ratio settings, follow in-
structions provided by the foam concentrate manufac-
turer.
Hose
Utilize fire hose that is rated by the hose manufacturer for
use with CAFS. Since the foam is formed during its transition
through the hoseline, it is important to utilize the minimum
recommended hose lengths, unless a static mixer is used.
There is significantly less friction and head loss with com-
pressed air foam as compared to water or foam solution;
therefore, effective fire streams can be achieved with longer
hose lays. Refer to the Suggested Guidelines for the Produc-
tion of Mid-Range Compressed Air Foam on Page 6.
NOTE: CAFS has the ability to produce a foam of
shaving cream consistency. While this type of foam is
highly stable and possesses a long drain time, it is
essential to ensure that the foam will release suffi-
cient water to extinguish a fire in a direct attack situa-
tion. This type of foam is typically suited for defensive
operations such as exposure protection, barriers or
fuels pretreatment.
WARNING
!
General Information
Electric Auto-Sync Control Panel
IL3012
