Carrier 42 SERIES Application Data

VALVE PACKAGES (cont)Two-Way Motorized Control ValveThe 2-way motorized valve motor drives valve openand a spring returns valve to normally closed position(no water flow with unit OFF).Supply connection at coil will be swage fit for field braze(standard) or union (option). Return connection at coilwill be factory brazed if isolation valve only. Addition ofany other component will require swage fit for field brazeor optional union connection.Check job specifications for system pressure, pres-sure drop limitations and flow rate prior to selecting valvepackage components or valve package size (1 ⁄29, 3⁄ 49,etc.).2-PIPE SYSTEM (One Valve Package) or 4-PIPE SYS-TEM (Two Valve Packages) Application:• 2 Pipe - Hydronic Heating Only• 2 Pipe - Hydronic Cooling Only• 2 Pipe - Hydronic Cooling with Total Electric Heat• 4 Pipe - Hydronic Cooling and HeatingNOTE: A 1⁄4-in. bypass line is included in the piping pack-age when a 2-way valve is specified with a control pack-age containing an automatic changeover device.Two-Way Motorized Control Valve withAquastat Bleed Bypass LineThe 2-way motorized valve motor drives valve openand a spring returns valve to normally closed position(no water flow through coil with unit OFF).The aquastat bleed bypass bleeds a small amount ofwater from supply to return when control valve is closed(required for system water temperature sensing by aqua-stat). Aquastat (A) clips on supply line upstream fromaquastat bleed bypass (as shown at right). It sensessystem water temperature to prevent cooling operationwith hot water in system piping or heating operation withchilled water in system piping. Additional aquastat re-quired to lock out the optional auxiliary electric heat whenhot water in system.Supply and return connections at coil will be swage fitfor field braze (standard) or unions (option).Check job specifications for system pressure, pres-sure drop limitations and flow rate prior to selecting valvepackage components or valve package size (1 ⁄29, 3⁄ 49,etc.).2-PIPE SYSTEM (One Valve Package) Application:• 2 Pipe - Hydronic Cooling and Heating• 2 Pipe - Hydronic Cooling and Heating with AuxiliaryElectric HeatNOTES: Additional aquastat required as noted above.18