R3 Controls, Valves, Accessories & Heat Pumps

R3 Controls, Valves, Accessories & Heat Pumps
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 R3 Controls, Valves, Accessories & Heat Pumps #2 Valves © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1
11/14/2018 Solenoid Valves The next slide is a cutaway view of the valve. Following that is an exploded view. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Solenoid Valve by Sporlan
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 Solenoid Valve by Sporlan Magnetic Coil Plunger Needle Seat Flow Direction The solenoid valve is the most frequently used component to control fluid flow. It has a magnetic coil that when energized will lift a plunger into the coil. Most of these valves are normally closed (NC) which means that the path for fluid flow closed until the valve coil is energized; then it opens. Solenoid valves control both liquid and vapor. They have a “snap-action” meaning they open and close quickly, they do not modulate fluid flow. Manual Lift Stem © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 Solenoid valve Solenoid Valve Magnetic Coil Plunger housing When installing these valves make sure they are upright (magnetic coil on top). Valves that are upside down or mounted on their side will have difficulty operating properly. Pilot-operated solenoid valves are used on larger applications. This type of valve uses a small valve seat to divert high-pressure gas that causes a larger valve to change position. Plunger / Needle Seat © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Solenoid Valve Operation
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 Solenoid Valve Operation 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 - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 Solenoid Valve Magnetic coil energized Plunger pulled up Power off Plunger drops This solenoid valve is in the NC (normally closed) position. The flow of liquid or vapor is stopped. When the magnetic coil is energized the plunger is raised and fluid passes under the disk and through the pipe in the direction of the arrow stamped on the side of the valve. Fluid flows Plunger Fluid stops Seat © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Pump-down Solenoid Operation
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 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 This valve is used as a liquid line “pump down” solenoid valve. The sequence is as follows: When the power is cut off, such as by a thermostat, the plunger drops, stopping the flow of refrigerant. Any fluid downstream of the valve is sucked out, or “pumped down”, by the compressor. This pulls all vapor out of the suction line so there is no migration during the off-cycle or flooding on startup due to vapor that has returned to liquid during the off-cycle. The low pressure control cuts off the compressor when its cut-out setting is reached. LIQUID LINE SOLENOID TEV THERMOSTAT 2. Tstat satisfied EVAPORATOR © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Pump-down Solenoid 11/14/2018 8. Compressor shuts off 14. Compressor starts 13. L.P. Control closes CONDENSER 12. Pressure rises 7. L.P. Control opens 9.Temperature rises in box 11. L.L.S. opens When the temperature in the refrigerated space rises, the tstat closes sending power to the solenoid. The valve opens and refrigerant flows through the evaporator. The pressure in the suction line rises, the contacts on the low pressure control close. The compressor starts. TEV 10.Tstat closes EVAPORATOR © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Improper installation
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 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 - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Solenoid Valve R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 Installed Backward Coil de-energized, plunger is down. It is a fairly common mistake to install this valve backward. The plunger may sound like it’s closing and opening properly, however, the high pressure fluid will push the disc up. This allows some refrigerant to seep through the valve. The small amount of refrigerant is enough to refrigerate the box below its thermostat setting because the compressor will not pump down low enough to shut off. Mark for flow direction Fluid from this direction would push up the valve seat Fluid pressure would help close valve © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Flooded Condenser Head pressure control
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 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 Condenser flooding raises head pressure as if the condenser were covered with a blanket Flooding, or backing up liquid, is similar to over-charging a system. Uses a HPR (Head Pressure Regulating) valve Maintains head pressure by restricting the flow of refrigerant trying to leave the condenser Bypasses hot gas to maintain pressures in receiver Advantages: very stable head pressures Disadvantages: difficult to diagnose & replace © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

REFRIGERATION CONDENSER Using head pressure regulator (HPR)
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 REFRIGERATION CONDENSER Using head pressure regulator (HPR) Standard operation: Ambient ABOVE 60o 210# Compressor C.C. HEATER Ambient 75o CONDENSER This is an example of how a system operates under “normal” 75º ambient conditions. In this example we would not even need head pressure controls. The R22 system pressure is 210 psig at this ambient. The pressures are the same everywhere in the high side of the system. The HPR valve is designed to only allow the hot gas to enter the receiver line if the condensing pressure falls below 180 psig. The liquid coming out of this condenser is above 180 psig, so it just flows through the HPR valve as if it were nothing more than an elbow in the piping system. RECEIVER 75º Ambient + 30º TD = 105º (210#) © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

REFRIGERATION CONDENSER Using head pressure regulator (HPR)
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 REFRIGERATION CONDENSER Using head pressure regulator (HPR) 11/14/2018 HPR raises head pressure when Ambient BELOW 60o 180# 180# 145# Pressure increases Compressor C.C. HEATER Ambient 50o CONDENSER When the ambient falls below 65º and the liquid coming out of the condenser is below 180#, the HPR valve is called into service. To increase the pressures to 180# the HPR valve closes the valve inlet from the condenser. This backs up the liquid in the condenser, increasing the head pressure. The pressures rise because the discharge vapor from the compressor doesn’t have enough room to condense. When the discharge pressure rises to 180# it forces the valve to open enough to mix some cool liquid from the condenser with hot gas from the compressor. The mixture leaves the valve and enters the receiver at 180#. This makes sure there is liquid for the metering device, and that it’s at a pressure high enough for the metering device to operate properly. RECEIVER Valve backs up refrigerant Valve mixes liquid & hot gas 50º Ambient + 30º TD = 80º (145#) © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 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 - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 HPR Valve R22 System 180# Valve Pressure 210# 210# Discharge vapor from Compressor To Receiver 180# valve less than 210# condensing Liquid from condenser Normal operation: Liquid from condenser goes direct to receiver Ambient 75o This is an enlarged view of the HPR valve. At a 75º ambient the pressure of 210# is above the valve pressure of 180# stored in the dome of the valve. The spring pressure under the valve disk ensures that the opening from the discharge gas will remain closed. Also, that the liquid will continue to flow directly from the condenser to the receiver. 75° Ambient + 30° = 105° (210#) Liquid from Condenser 210# © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Ambient falls, pressure falls
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 Ambient falls, pressure falls The following slide shows how condensing pressure falls as ambient falls. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 HPR Valve R22 System 180# Valve Pressure 145# 145# Discharge vapor from Compressor To Receiver Low receiver pressure 180# Valve is more than 145# condensing Ambient 50o In this enlarged view of the HPR valve, the ambient has dropped to 50º The condensing temperature has dropped to 80º ( ) which has a condensing pressure of about 145# for R22. At 145# the metering device at the evaporator will start feeding erratically. The pressure on the device’s inlet is so low that it can’t maintain the proper pressure difference it was designed to maintain. The HPR valve must do something to bring the pressures up to the minimum setting of 180# 50° Ambient + 30° = 80° (145#) Condenser Liquid from 145# © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 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 - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

HPR Valve R22 System R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 180# 180# Valve Pressure 180# Discharge vapor from Compressor To Receiver Discharge increases to180# 180# mixture liquid/hot gas Valve backs up condenser 180# Valve more than 145# condensing Ambient 50o When the liquid from the condenser entering the inlet of the valve falls below 180#, the valve reacts. First, the 180# pressure charge stored in the head of the valve pushes against the lower pressure at the valve inlet of 145#. This closes the inlet of the condenser, backing up the liquid into the condenser. The discharge pressures start to rise because there isn’t any room for them to condense. Next, the discharge pressures get to 180#, pushing past the disk and enters the line to the receiver. As the pressures climb in the condenser, the liquid on the inlet valve starts to open the disk in the HPR. This allows the cool liquid to mix with the hot discharge gas. Together they move down the line to the receiver at 180#. 50° Ambient + 30° = 80° (145#) Condenser Liquid from Condenser Liquid from 145# 180# Liquid increases to 180# © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Evaporator Pressure Regulator
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 Evaporator Pressure Regulator © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Evaporator Pressure Regulator (EPR) valve
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 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 - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Refrigeration System Components
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 Evaporator Pressure Regulator Compressor Condenser Metering Device Evaporator EPR valves are usually located on the outlet of the evaporator on a single evaporator system. These are often used in commercial refrigeration on deli display cases. There is so much tubing in these cases that a pump-down would take a long time and cause the coil t become very cold. So the EPR keeps the pressure up, keeping the case temperature up. EPR © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 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 - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

E P R ORI 11/14/2018 Evaporator Pressure Regulator O.R.I. Valve Start-Up: Opens on Rise of Inlet Pressure Box & R22 Suction Gas @ 68 psig (40º F) Valve requirements: Maintain 33° minimum evaporator (59 psig for R22) Outlet to Compressor 40o EPR valves Open on a Rise of Inlet pressure (ORI). In this example the EPR is on the outlet of the evaporator in a 40° box at start-up. The R22 system has a pressure of 68 psig and the valve is wide open. The pressure and temperature are the same on both the inlet and the outlet. Valve wide open Inlet from Evaporator 68# @ 40o © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

E P R Design conditions 11/14/2018 Evaporator Pressure Regulator Evaporator down to 59# (33º F) Design Conditions Valve starts to close down Outlet to Compressor 33o This slide shows that the pressure has dropped to 59 psig and the temperature is down to 33°. This is the coldest temperature that we want to have in this evaporator system. Inlet from Evaporator 59# @ 33o © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 Adjusting the EPR Adjust if pressure drops below 59 psig Valve will maintain this setting © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

E P R Adjustment 11/14/2018 Evaporator Pressure Regulator Adjustment Needed Outlet to Compressor 25o The compressor continues to run because it is trying to refrigerate other systems. The valve is experiencing 49 psig suction pressure which is a lower pressure than is desired. The EPR is adjusted to “hold back” the pressure in the evaporator to 59 psig therefore, it closes down the inlet from the evaporator enough to maintain that pressure. Valve will now maintain 59 psig no matter how low the outlet drops Evaporator temperature continues to drop Inlet from Evaporator 59# @ 33o 49# @ 25o © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

EPRs and Multiple Evaporators
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 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 When two or more evaporators are used with one compressor, one of them may be at a different temperature and pressure range. An EPR is needed in the suction line of the higher temperature evaporator(s). If one evaporator operates at 25° and another at 40°, the EPR would be used on the 40° evaporator. When setting the EPR use the gauge port on the inlet (evaporator side) of the valve. It has a Shrader core which will allow you to install your gauge hose on it while the system is operating. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

EPR Application 11/14/2018 Compressor Compressor tries to pull Candy Case evaporator down to 25° Candy Case 50º Box 49# 49# Evaporator In this illustration we will start with a walk-in cooler that maintains a space temperature of 35°. When the compressor is running the evaporator temperature is about 25°. If we add a candy case to the same system the suction pressure of the candy case will also be 49 psig with a 25° evaporator. The candy case is supposed to have a box temperature of 50° with an evaporator pressure of 59 psig and an evaporator temperature of 33°. This desired condition can be accomplished by installing an EPR valve on the outlet of the candy case evaporator and adjusting accordingly. Walk-In Cooler 35º Box EPR keeps the pressure up Evaporator 59# © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Sporlan Electric EPR valve
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 Sporlan Electric EPR valve Electronic EPRs are now being used. They are more responsive than the mechanical version. Also, they can operate in response to box, or coil temperature rather than pressure. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Crankcase Pressure Regulators (CPR) by Sporlan
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Crankcase Pressure Regulator (CPR) valve
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 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) A CPR valve looks like an EPR, but it has a different function. It is located in the suction line, but close to the inlet of the compressor. The valve bellows responds to the crankcase pressure of the compressor. The gauge port on the suction service valve will show what pressure the compressor is working under. The gauge port on the inlet of the valve will show what pressure is trying to go to the compressor from the evaporator. The valves function is to keep the crankcase pressure low enough to prevent the compressor from going out on overload if the pressure from the evaporator gets too high. A low-temperature compressor may need this overloading protection during a hot pull down. This condition may occur after defrost, on start up of a warm box, or if warm product is put into the freezer. When the evaporator temperature is high, the evaporator pressure is high. The compressor is a constant-volume pump. It is designed to pump low density cold vapor in a freezer. When the pressure increases the compressor tries to pump the same volume of what is now high density vapor. This will create a motor overload condition when the motor draws more than 10% above its rated amps. The CPR valve is referred to as a Close on Rise of Outlet (CRO) valve. The valve closes when the outlet (compressor pressure) is higher than its setting. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Crankcase Pressure Regulator
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 Refrigeration System Valves 11/14/2018 Crankcase Pressure Regulator C.P.R. Compressor Condenser Metering Device Evaporator EPR © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Crankcase Pressure Regulator
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 Crankcase Pressure Regulator 11/14/2018 © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 Crankcase Pressure Regulator C P R ORI C.R.O. Valve Standard Conditions: Closes on Rise of Outlet Pressure Box & R404A Suction Gas @ 33# (0º F) Inlet from Evaporator 33# As already stated, CPR valves Close on a Rise of Outlet pressure (CRO). In this example the CPR is on the inlet of the compressor on a low temperature system that has a normal operating suction pressure of 33 psig (0° evaporator temperature). Outlet to Compressor 33# © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 Hot-Pull Down Defrost warms evaporator, pressures rise After defrost, compressor starts High pressures can overload compressor © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 Crankcase Pressure Regulator C P R Hot PullDown Evaporator up to 115# (55º F) Start up after defrost "Hot Pull Down" Compressor draws high current and cuts out on overload Inlet from Evaporator 115# During “hot pull down” after defrost the pressures are very high. The compressor will run at higher amperage than normal. Sometimes the amperage is so high that the compressor will cut out on its overload. Outlet to Compressor 115# © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Adjusting the CPR Valve
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 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 Adjusting the CPR should be done on a hot pull down, or at least when the compressor has enough load to run at a higher amperage than normal. Install an ammeter on one of the compressor power supply wires. Front seat the suction service valve so that the compressor will only have to draw the light load of it’s own crankcase pressure on start up. Start the compressor. Open the suction service valve by backing the stem out. Stop when the amp draw of the compressor reaches 10% over its rated amperage. For example, if the compressor RLA is 20 amps, add 10% or 2 amps. The compressor draw at 10% over its rated amps is or 22 amps. Now adjust the CPR valve closed until the amp draw drops to the rated amps (20 amps in the above example). That will be the maximum pressure that the compressor will have to operate under, even on a hot pull down. NOTE: Before leaving make sure you fully back seat the suction service valve. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 Crankcase Pressure Regulator C P R Adjustment Evaporator up to 115# (55º F) To lower outlet pressure Adjustment Needed Inlet from Evaporator Compressor draws normal current when pressure returns to "normal" operating range 115# This slide shows that the evaporator pressure at 55° is 115# and will cause the compressor amperage to be too high. To correct the overloading of the motor we adjust the CPR down to 33 psig (suction temperature of 0°). This is the “Normal” evaporator temperature and operating conditions for the compressor. The compressor amperage should now be within its normal operating range. Outlet to Compressor 115# 33# @ 0o © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 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 The suction valve is usually used to find out what the suction pressure is and for charging and evacuation. However, it can be used to throttle the flow of suction gas to see if it has any affect on the compressor. Front seating the valve will isolate the compressor from the suction line. The valve stem cap is the most underrated part of the assembly. Its primary purpose is to keep the valve stem clean and free of rust. A dirty or rusty valve stem will damage the packing gland and allow refrigerant to leak out of the system. The threads on the valve cap are not designed to contain the leaking refrigerant. On larger valves the the packing gland should be loosened before adjusting the valve stem, but must be tightened when service is complete. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 Suction Service Valve Inlet Valve Seat Gauge Port Packing Packing Nut This slide shows an oversized valve to better illustrate the parts of the service valve. Valve Stem © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 Suction Service Valve Valve positions: Back seated Normal position, backed out all the way Mid-seated or “cracked” Service position, opens gauge port Front seated Closes suction line, run in all the way Compressor is isolated from system The suction valve is usually used to find out what the suction pressure is and for charging and evacuation. However, it can be used to throttle the flow of suction gas to see if it has any affect on the compressor. Front seating the valve will isolate the compressor from the suction line. The valve stem cap is the most underrated part of the assembly. Its primary purpose is to keep the valve stem clean and free of rust. A dirty or rusty valve stem will damage the packing gland and allow refrigerant to leak out of the system. The threads on the valve cap are not designed to contain the leaking refrigerant. On larger valves the the packing gland should be loosened before adjusting the valve stem, but must be tightened when service is complete. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Valve “Cracked” R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 This slides shows how system pressure shows up on the gauges when the valve is “cracked” or mid-seated. Valve “Back Seated” © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

“Front Seated” 11/14/2018 Purge Vapor Pssst With the suction valve front seated and the compressor running the gauge, valve, and crankcase are pulled down. If the compressor is left to run long enough it will pull into a vacuum. Compressor now “isolated” from suction side of system © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Discharge Service Valves
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 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. The discharge service valve is basically the same as the suction service valve. However, you cannot front seat the valve while the compressor is running. To do so will blow out the compressor discharge valves in a matter of seconds. When both the suction and discharge service valves are front seated the compressor is totally isolated. It can now be serviced or replaced. When ready to put the compressor back in service the technician need only to pull a vacuum on the compressor, then open the valves and turn on the power. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Suction Valve 11/14/2018 Discharge Valve “Back Seated” © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 Valve “Cracked” This slide shows how to check system pressures by cracking the discharge service valve. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 Purge Discharge Gas Front Seated Pssst Front seating the discharge valve and purging it will isolate the high pressure side of the system. CAUTION: Never front seat the discharge service valve when the compressor is running. It will blow out the compressor discharge valves. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Compressor is Isolated
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 Compressor is Isolated The compressor is now ready for: Valve plate replacement Crankcase oil change Compressor replacement The following slides show the basics of semi-hermetic compressor replacement. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Replacing a semi-hermetic compressor
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 Valves Front Seated 11/14/2018 Compressor Isolated Replacing a semi-hermetic compressor Replace Compressor If you have to replace the compressor front seat both the suction and discharge service valves. Unbolt the valves and pull them away from the compressor. To replace the valve plate the procedure is much the same. Except, instead of unbolting the service valves you unbolt the head to get to the valve plate. SAFETY NOTE: Make sure the pressure in the compressor has been purged. Leave the gauges OPEN in case some of the refrigerant is under the oil and is boiling off slowly. It doesn’t take much pressure to turn the steal head into a flying metal discus when the bolts are removed. Keep you gauges on the unit so you can see if the pressures are rising. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 Ambient air Ambient air Old compressor removed Remove the old compressor. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 New Compressor In Place Set the new compressor in place and reconnect the service valves. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

11/14/2018 Evacuate Service Valves And New Compressor Body ONLY You only have to evacuate the compressor body because by front seating the valves all the refrigerant is still in the system. Note, this works well for compressors that are not a burnout or contaminated in some way. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

Open suction service valve
R3 Controls, Valves, Accessories & Heat Pumps - Subject 2 Valves v1.1 11/14/2018 Open suction service valve Open discharge service valve Start Compressor After the evacuation is done open the service valves and let the pressures equalize in the compressor. Then start up and check out the new compressor. © 2004 Refrigeration Training Services - R3 Subject 2 Valves v1.2 © 2004 Refrigeration Training Services No reproduction or unauthorized use allowed

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R3 Controls, Valves, Accessories & Heat Pumps

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