Service Valves - Lennox Merit 10HPB Series Installation Instructions Manual

10HPB Manifold Gauge Connections (Cooling Cycle)
defrost thermostat
expansion/
check valve
low high
pressure pressure
gauge manifold
to
liquid line
HCFC−22
service
drum
Note − Arrows indicate the direction of refrigerant flow.

Service Valves

The liquid line and vapor line service valves (figures 13 and
14) and gauge ports are used for leak testing, evacuating,
charging and checking charge. See table 3 for torque re-
quirements.
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
IMPORTANT
Service valves are closed to the outdoor unit and
open to line set connections. Do not open the valves
until refrigerant lines have been leak tested and
evacuated. All precautions should be exercised to
keep the system free from dirt, moisture and air.
biflow
filter / drier
muffler
compressor
port
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
Outdoor Unit
distributor
reversing valve
outdoor
coil
vapor
service
port
Figure 12
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.
To Open Liquid or Vapor Line 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 Liquid Line 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.
Ball−Type Vapor Line 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.
Page 11
Indoor Unit
vapor
line
valve
expansion/check
valve
indoor
coil