Service Valves - Lennox 12HPB Series Installation Instructions Manual

12HPB Manifold Gauge Connections (Cooling Cycle)
defrost thermostat
expansion/
check valve
low high
pressure pressure
GAUGE MANIFOLD
to
liquid line
HCFC−22
service
drum
port
Note − Arrows indicate direction of the refrigerant flow.

Service Valves

The liquid line and vapor line service valves (figures 13 and
14) and and gauge ports are used for leak testing, evacuat-
ing, charging and checking charge. See table 3 for torque
requirements.
Each valve is equipped with a service port which has a fac-
tory−installed Schrader valve. A service port cap protects
the Schrader valve from contamination and serves as the
primary leak seal.
Table 3
Torque Requirements
Part
Service valve cap
Sheet metal screws
Machine screws #10
Compressor bolts
Gauge port seal cap
To Access Schrader Port:
1 − Remove service port cap with an adjustable wrench.
2 − Connect gauge to the service port.
3 − When testing is completed, replace service port cap.
Tighten finger tight, then an additional 1/6 turn.
Outdoor Uni
distributor
biflow
filter / drier outdoor
coil
muffler
compressor
Recommended Torque
8 ft.− lb. 11 NM
16 in.− lb. 2 NM
28 in.− lb. 3 NM
90 in.− lb. 10 NM
8 ft.− lb. 11 NM
t
reversing valve
vapor
vapor
service
port
valve
Figure 12
To Open Service Valve:
1 − Remove stem cap with an adjustable wrench.
2 − Use a service wrench with a hex head extension to back
the stem out counterclockwise as far as it will go.
NOTE − Use a 3/16" hex head extension for liquid line
sizes or a 5/16" extension for vapor line sizes.
3 − Replace stem cap. Tighten finger tight, then tighten an
additional 1/6 turn.
To Close Service Valve:
1 − Remove stem cap with an adjustable wrench.
2 − Use a service wrench with a hex head extension to turn
the stem clockwise to seat the valve. Tighten firmly.
NOTE − Use a 3/16" hex head extension for liquid line
sizes or a 5/16" extension for vapor line sizes.
3 − Replace the stem cap. Tighten finger tight, then tighten
an additional 1/6 turn.
Vapor Line (Ball−Type) Service Valve
Vapor line service valves function the same way as the oth-
er valves, the difference is in the construction. These
valves are not rebuildable. If a valve has failed, you must
replace it. A ball valve valve is illustrated in figure 14.
The ball valve is equipped with a service port with a factory−
installed Schrader valve. A service port cap protects the
Schrader valve from contamination and assures a leak−
free seal.
Page 11
Indoor Uni
line
expansion/check
valve
t
indoor
coil