Master Valves (3 To 5 Zone Outdoor Units); Mlb And Mpc Multi-Zone Outdoor Unit Connections And Line Set Usage - Lennox MMA018SM4 Service Manual

9. Master Valves (3 to 5 Zone Outdoor Units)

• 3-zone, 4-zone and 5-zone (not 2-zone) multi-zone
units have a master valve on each refrigerant line.
• The master valve controls refrigerant to all of the zone-
supply valves.
• Open the master valves prior to opening the zone-
supply valves.

10. MLB and MPC Multi-Zone Outdoor Unit Connections and Line Set Usage

MPC024S4M
Number of Zones and Outdoor Unit Connection Sizes
NOTE - Letter = Indoor Unit Zone Connection on Outdoor Unit
Zone 1 (A)
1/4 in. liq + 3/8 in. gas
012
018
009
012
018
012
018
018
006
009
012
018
Zone 2 (B)
1/4 in. liq + 3/8 in. gas 1/4 in. liq + 3/8 in. gas
006
006
009
009
009
012
012
018
006
006
006
006
Liquid Line
Master Valve
Vapor Line
Master Valve
Zone 3 (C)
- - -
- - -
- - -
- - -
- - -
- - -
- - -
- - -
006
006
006
006
54