R 3 Controls Valves Accessories Heat Pumps 2

R 3 Controls, Valves, Accessories & Heat Pumps #2 Valves © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2

Solenoid Valves The next slide is a cutaway view of the valve. Following that is an exploded view. © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 2

Magnetic Coil Plunger Solenoid Valve by Sporlan Needle Seat Flow Direction Manual Lift Stem © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 3

Solenoid valve Solenoid Valve Magnetic Coil Plunger housing Plunger / Needle Seat © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 4

Solenoid Valve Operation 1. 2. 3. 4. Magnetic coil energized, lifts plunger Fluid lifts seat, flows through valve Magnetic coil de-energized, plunger falls Fluid pressure on seat helps close valve © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 5

Solenoid Valve Magnetic coil energized Plunger pulled up Power off Plunger drops Plunger Fluid stops Fluid flows Seat © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 6

Pump-down Solenoid Operation 1. Thermostat calling, Compressor is running LOW PRESSURE CONTROL 5. Suction line refrigerant stored in receiver CONDENSER 6. As system pumps down suction pressure falls 3. Liquid Line Solenoid De-Energized 4. Shuts off flow of refrigerant LIQUID LINE SOLENOID TEV EVAPORATOR © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 THERMOSTAT 2. Tstat satisfied 7

Pump-down Solenoid 8. Compressor shuts off 14. Compressor starts 13. L. P. Control closes 7. L. P. Control opens CONDENSER 12. Pressure rises 9. Temperature rises in box 11. L. L. S. opens TEV EVAPORATOR © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 10. Tstat closes 8

Improper installation • Flow direction marked on valve – Look for an arrow or the word “in” • They will leak through if installed backward © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 9

Solenoid Valve Installed Backward Coil de-energized, plunger is down. Fluid from this direction would push up the valve seat © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 Mark for flow direction Fluid pressure would help close valve 10

Flooded Condenser Head pressure control Condenser flooding: • Same effect as overcharging the unit HPR (Head Pressure Regulating) valve: • Restricts liquid flow out of condenser • Raises head pressure • Bypasses some hot gas to receiver © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 11

REFRIGERATION CONDENSER Using head pressure regulator (HPR) Standard operation: Ambient ABOVE 60 o CONDENSER Ambient 75 o 75º Ambient + 30º TD = 105º (210#) © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 RECEIVER 12

REFRIGERATION CONDENSER Using head pressure regulator (HPR) HPR raises head pressure when Ambient BELOW 60 o Pressure increases CONDENSER Ambient 50 o Valvemixes backsliquid up refrigerant Valve & hot gas 50º Ambient + 30º TD = 80º (145#) © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 RECEIVER 13

Inside view of an HPR Following slide example: • HPR rating is 180 psig – Valve inactive above 180 condensing pressure • Example has 210 psig condensing pressure – Higher than valve’s rating – HPR will not bypass hot gas – Liquid from condenser goes directly to receiver © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 14

HPR Valve R 22 System 180# Valve Pressure Discharge vapor from Compressor To Receiver 180# valve less than 210# condensing Normal operation: Liquid from condenser goes direct to receiver Liquid from condenser Ambient 75 o 75° Ambient + 30° = 105° (210#) Liquid from Condenser © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 15

Ambient falls, pressure falls The following slide shows how condensing pressure falls as ambient falls. © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 16

HPR Valve R 22 System 180# Valve Pressure Discharge vapor from Compressor To Receiver Low receiver pressure 180# Valve is more than 145# condensing Ambient 50 o 50° Ambient + 30° = 80° (145#) Liquid from Condenser © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 17

HPR valve is activated • • • The HPR restricts condenser outlet This backs up liquid into condenser The head pressure increases to 180 psig Valve allows some gas and liquid to pass Mixture (at 180 psig) goes to receiver © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 18

HPR Valve R 22 System 180# Valve Pressure Discharge vapor from Compressor To Receiver Discharge increases to 180# mixture liquid/hot gas Valve backs up condenser 180# Valve more than 145# condensing Ambient 50 o Liquid from Liquid Condenser © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 50° Ambient + 30° = 80° (145#) Liquid increases to 180# 19

Evaporator Pressure Regulator © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 20

Evaporator Pressure Regulator (EPR) valve • Opens on Rise of Inlet (ORI) pressure • Location: In the Suction line • Senses: Evaporator pressure • Purpose: Keeps evaporator pressure/temperature up Maintains set temperature of product © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 21

Refrigeration System Components Evaporator Pressure Regulator Compressor Evaporator Condenser Metering Device EPR © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 22

EPR Valve Setting • The following EPR is set to maintain a minimum evaporator pressure of 59 psig • On start up the pressure is 68 psig • As the compressor runs the pressure falls © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 23

E P R ORI Evaporator Pressure Regulator O. R. I. Valve Start-Up: Box & R 22 Suction Gas @ 68 psig (40º F) Opens on Rise of Inlet Pressure Valve requirements: Maintain 33° minimum evaporator (59 psig for R 22) 68# @ 40 o Outlet to Compressor Valve wide open Inlet from Evaporator 68# @ 40 o © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 24

E P R Design conditions Evaporator Pressure Regulator Evaporator down to 59# (33º F) Design Conditions Valve starts to close down Inlet from Evaporator 59# @ 33 o Outlet to Compressor 59# @ 33 o © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 25

Adjusting the EPR • Adjust if pressure drops below 59 psig • Valve will maintain this setting © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 26

E P R Adjustment Evaporator Pressure Regulator Adjustment Needed 49# @ 25 o Evaporator temperature continues to drop Inlet from Evaporator 49# 59# @ 33 25 oo @ © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 Outlet to Compressor Valve will now maintain 59 psig no matter how low the outlet drops 27

EPRs and Multiple Evaporators Evaporator #1: • Walk-in refrigerator (25° Evaporator) Evaporator #2: • Candy case (33° Evaporator) Where do you install the EPR? • Near the highest temperature evaporator © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 28

EPR Application 25º @ 49# Evaporator 25º @ 49# Compressor tries to pull Candy Case evaporator down to 25° Candy Case 50º Box Walk-In Cooler 35º Box EPR keeps the pressure up © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 Evaporator 33º @ 59# 29

Sporlan Electric EPR valve © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 30

Crankcase Pressure Regulators (CPR) by Sporlan © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 31

Crankcase Pressure Regulator (CPR) valve • Looks like an EPR, but… Closes on Rise of Outlet (CRO) pressure • Location: Suction line near compressor • Senses: Compressor crankcase pressure • Purpose: Keeps crankcase pressure down Prevents compressor overload during hot pull down (after freezer defrost) © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 32

Refrigeration System Valves Crankcase Pressure Regulator C. P. R. Compressor Evaporator Condenser Metering Device EPR © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 33

Crankcase Pressure Regulator © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 34

C P R ORI Pressure Regulator Crankcase C. R. O. Valve Standard Conditions: Box & R 404 A Suction Gas @ 33# (0º F) Closes on Rise of Outlet Pressure 33# Outlet to Compressor Inlet from Evaporator 33# © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 35

Hot-Pull Down • Defrost warms evaporator, pressures rise • After defrost, compressor starts • High pressures can overload compressor © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 36

Crankcase Pressure Regulator C P R Hot Pull. Down Evaporator up to 115# (55º F) Start up after defrost "Hot Pull Down" Compressor draws high current and cuts out on 115# Inlet from Evaporator overload Outlet to Compressor 115# © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 37

Adjusting the CPR Valve • • • Adjust when compressor is overloaded Install ammeter on the compressor Front seat suction service valve Start compressor Open suction valve until compressor draws 10% more than Run Load Amps (RLA) • Adjust CPR until compressor draws RLA • Back seat suction valve © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 38

Crankcase Pressure Regulator C P R Adjustment Evaporator up to 115# (55º F) To lower outlet pressure Adjustment Needed Compressor draws normal current when pressure returns to "normal" operating range Outlet to Compressor 115# Inlet from Evaporator 115# 33# @ 0 o © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 39

Suction Service Valve Location: – Suction side (inlet) of compressor Purposes: – Check suction pressure – Check compressor valves – Isolate compressor The following slide shows the major parts of a service valve © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 40

Suction Service Valve Inlet Valve Seat Gauge Port Packing Nut Valve Stem © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 41

Suction Service Valve positions: 1. Back seated • Normal position, backed out all the way 2. Mid-seated or “cracked” • Service position, opens gauge port 3. Front seated • • Closes suction line, run in all the way Compressor is isolated from system © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 42

Valve “Cracked” Valve “Back Seated” © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 43

“Front Seated” Purge Vapor Pssst Compressor now “isolated” from suction side of system © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 44

Discharge Service Valves Location: – Discharge side of compressor Purpose: – Check discharge pressure – Isolate compressor Caution: Never front seat the discharge valve when the compressor is running. © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 45

Suction Valve Discharge Valve “Back Seated” © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 46

Valve “Cracked” © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 47

Purge Discharge Gas Front Pssst Seated © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 48

Compressor is Isolated The compressor is now ready for: 1. Valve plate replacement 2. Crankcase oil change 3. Compressor replacement The following slides show the basics of semi-hermetic compressor replacement. © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 49

Valves Front Seated Replacing a semi-hermetic compressor © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 Compressor Isolated 50

Ambient air Old compressor removed © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 51

New Compressor In Place © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 52

Evacuate Service Valves And New Compressor Body ONLY © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 53

Open suction service valve Open discharge service valve Start Compressor © 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 54

© 2004 Refrigeration Training Services - R 3 Subject 2 Valves v 1. 2 55