Komatsu 830E-AC Shop Manual page 943

Manifold Gauge Set
A typical manifold gauge set (Figure 4-10) has two
screw type hand valves to control access to the sys-
tem, two gauges and three hoses. The gauges are
used to read system pressure or vacuum. The mani-
fold and hoses are for access to the inside of an air
conditioner, to remove air and moisture, and to put
in, or remove, refrigerant from the system. Shutoff
valves are required within 12 inches of the hose
end(s) to minimize refrigerant loss.
A gauge set for R-134a will have a blue hose with a
black stripe for the low side, a red hose with a black
stripe for the high side, and a yellow hose with a
black stripe for the utility (center) hose. The hoses
use a 1/2 in. ACME female nut on the gauge end.
Special quick disconnect couplings are normally
combined with a shutoff valve on the high and low
side hoses. The free end of the center hose contains
a 1/2 in. ACME female nut and a shutoff device
within 12 inches of the hose end. These special
hoses and fittings are designed to minimize refriger-
ant loss and to preclude putting the wrong refrigerant
in a system.
NOTE: When hose
necessary, the new hoses must be marked "SAE
J2916 R-134a".
Functions of the manifold gauge set are included in
many of the commercially available recovery or
recovery/recycle stations.
N04031 10/06
replacement becomes
Operator Comfort
FIGURE 4-10. MANIFOLD GAUGE SET
Low Side Gauge
The low side gauge, registers both vacuum and pres-
sure. The vacuum side of the scale is calibrated from
0 to 30 inches of mercury (in. Hg). The pressure side
of the scale is calibrated to 150 psi.
Never open the hand valve to the high side at
anytime when the air conditioning system is
operating. High side pressure, if allowed, may
rupture charging containers and potentially
cause personal injury.
High Side Gauge
The high side gauge is used to measure pressure
only on the discharge side of the compressor. The
scale is calibrated from 0 to 500 psi.
N4-17