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Oil System Components

COPELAND OIL PUMP

OIL LEVEL CONTROLLER

SENTRONIC transducer lower right corner of pump. Once again this transducer is a NORMALLY closed switch. Meaning when oil pressure is sensed the switch stays closed, when the transducer senses less than 9 PSI it will open, thus shutoff contactor to compressor.

Where the oil line comes in there is a little mesh screen in series. To clean this screen shut oil line off, remove oil line flare nut, use either degreaser or electrical contact cleaner, spray it clean until you can see light through it for 360 degrees. Also you will notice just above the oil inletis a cap, now under that cap is how you adjust the float level, with your service wrench turn the service nut CLOCKWISE 1/4 turn wait 15 minutes, or to lower the float level turn the service nut COUNTER CLOCKWISE 1/4 turn and also wait 15 minutes to see where the level settles. NOTE: Do not lose the screen or throw it out, the brass flare in which the screen is attached to is part of the flare nut assembly you will need it to tighten the flare nut to get a proper seal.

INTERNAL OIL FILTER SCREEN

(COPELAND)

Electronic Oil Filler Valve

This screen goes in the BOTTOM left of the block that has either two bolt heads that are 1/2″ or a BIG nut that is 1 7/16″ BIG socket. NOTE: To clean this screen us either a spray degreaser or electrical contact cleaner.

These are very common to find on SCROLL compressors. NOTE: If you have a compressor shutoff on oil filler alram, how you will know is there will be a “RED LIGHT” instead of a green light simply unplug the 24 volt incoming power plug wait 10 seconds then plug it back in and it should start filling with oil again.

OCV VALVE

Oil Separator Float Plate

This valve is for when too much pressure builds up in the oil reservoir. It will relieve itself into the suction line (Spring loaded) inside. The OCV valves come in different pressures like a 5, 20,30 with this being said it is a good idea to carry at least one OCV-20 , because if you have a case where you run into an OCV-5 on a rack and it is allowing pressure to bypass into the suction line evidenced of constant oil failures on multiple compressors and the oil resevoir is empty.   Installing an OCV-20 should eliminate that problem.

Copper line coming out goes thru an OF303 Filter into the TOP of the oil reservoir tank. NOTE: If you are having oil feeding problems from the oil separator,feel the copper line with your hand if it is “COLD” then oil is NOT feeding, if it is “HOT” then more than likely oil IS passing through it.

OIL LINE COMING FROM SEPERATOR.

3GS MINERAL OIL

This copper line is coming from the bottom of the oil seperator goes through the oil filter into the oil resevoir tank then finally to the compressors. Now notice there is a solenoid in series, if you ever encounter the resevoir tank full and the compressors are oil starved, you may have one of two issues the solenoid has gone bad or the oil filter is plugged solid. This solenoid should have power at ALL times. The reason behind this is the solenoid is connected via AUX contacts on contactors so as long as one compressor is running the solenoid will stay open, if ALL the compressors shutoff the solenoid will shutoff as a safety measure to keep the oil and refrigerant from condensing in either the resevoir or the compressors themselves, better to hold the oil and refrigerant in the seperator. So here are some tips to troubleshooting:

1) If ALL compressors are off then immediately turn off the hand valve or ball valve on the oil line coming out of the bottom of the oil seperator.

2)Troubleshoot why all compressors are off.

3)Once the compressors are running check for power at the solenoid , if there is power and solenoid is energized then check oil filter.

4)Let compressors run for 30 minutes then OPEN the ball valve or hand valve coming out of the bottom of the oil seperator.

Mineral oil is mostly used for R22,408a,MP39,HP80 and some of the other refrigerants that came out after R12 and 502 was banned.

SPORLAN ROF 413-T OIL FILTER

OCV ON TOP OF OIL RESEVOIR TANK

This particular type of oilfilter has a cartridge inside it. How it works is the oil comes in goes down the center of the filter and comes out the side and onto the resevoir then to the compressors via the oil level controller.

Another picture of an OCV valve that sits on top of the oil resevoir. Something to check if you are ever having problems with the oil level controllers not geting proper oil flow to compressors, sometimes what will happen is people will put 5PSI valves on top instead of a 20-30 and the pressure will relieve itself into the suction line instead of the pressure being used to feel the controllers thus getting oil to the compressors.

WESTERMEYER OIL SEPERATOR

DIFFERENTIAL GAUGE

What you see here is an oil seperator, there is a filter inside it, same principal as any other oil seperator, the discharge gas goes through the filter and is rung out hence causing the oil to fall to the bottom of the vessel, now there is a float valve on the bottom, when the bottom of the vessel has enough oil in it, it will cause the ball to lift thus sending the oil to the resevoir then to the compressors where its most needed.

The purpose of this gauge is to give an indication if the filter inside the oil seperator needs to be changed, as long as it is the green area all is good, now when the needle swings over to the yellow or red area this indicates the filter is need of changing. NOTE: The hoses are connected to the discharge line in and out of the seperator  for differential indication.

OIL INLET FOR OIL LEVEL CONTROLLER

CHECKING NET OIL PRESSURE

(NOP)

Notice the purple item blocking the hole, this is a copper crush sleeve or an “O” ring for the inside  to form a better seal on a flare fitting, this is shown because if you ever have a problem with oil NOT filling up the oil level controller this is something to look at.

Here is an illustration of how to check your Net Oil Pressure, by putting your gauges on the suction line and on the oil pump itself, then you SUBTRACT the SUCTION pressure from the OIL PRESSURE coming off the oil pump (STATIC OR DYNAMIC) pressure. (NOTE) Not unusal to see to see numbers anywhere from 38-54 PSI (Not exact hard numbers but appromately) on Copeland compressors, now on Carlysle compressors the oil pressure will be much lower.

COPELAND OIL PUMP

SENTRONIC transducer lower right corner of pump. Once again this transducer is a NORMALLY closed switch. Meaning when oil pressure is sensed the switch stays closed, when the transducer senses less than 9 PSI it will open, thus shutoff contactor to compressor.

OIL LEVEL CONTROLLER

Where the oil line comes in there is a little mesh screen in series. To clean this screen shut oil line off, remove oil line flare nut, use either degreaser or electrical contact cleaner, spray it clean until you can see light through it for 360 degrees. Also you will notice just above the oil inletis a cap, now under that cap is how you adjust the float level, with your service wrench turn the service nut CLOCKWISE 1/4 turn wait 15 minutes, or to lower the float level turn the service nut COUNTER CLOCKWISE 1/4 turn and also wait 15 minutes to see where the level settles.

INTERNAL OIL FILTER SCREEN

(COPELAND)

This screen goes in the BOTTOM left of the block that has either two bolt heads that are 1/2″ or a BIG nut that is 1 7/16″ BIG socket. NOTE: To clean this screen us either a spray degreaser or electrical contact cleaner.

Electronic Oil Filler Valve

These are very common to find on SCROLL compressors. NOTE: If you have a compressor shutoff on oil filler alram, how you will know is there will be a “RED LIGHT” instead of a green light simply unplug the 24 volt incoming power plug wait 10 seconds then plug it back in and it should start filling with oil again.

OCV VALVE

This valve is for when too much pressure builds up in the oil reservoir. It will relieve itself into the suction line (Spring loaded) inside.

Oil Separator Float Plate

Copper line coming out goes thru an OF303 Filter into the TOP of the oil reservoir tank. NOTE: If you are having oil feeding problems from the oil separator,feel the copper line with your hand if it is “COLD” then oil is NOT feeding, if it is “HOT” then more than likely oil IS passing through it.

More Oil System Components

OF-303 OIL FILTER

Oil Differential Valve

This is the most popular oil filter that is used on rack systems. If you get a call for a compressor OFF and you find it is off on oil failure control and the date is more than ONE year on the oil filter, CHANGE IT OUT. NOTE: T means tap, to check pressure.

What this valve does is to create a differential of pressure (25psi) for the oil feeding system on rack compressors that have LOW/MEDIUM temperature discharge lines all on one common header. Because the low temperature compressors have a LOWER crankcase pressure and the medium temperature compressors have a HIGHER crankcase pressure this valve will keep the LOW temp compressors from taking all the oil and the medium temp compressors getting nothing, this valve evens it all out so ALL the compressors get equal oil feeding them. NOTE: There is a screen on the inlet of the valve, not uncommon for it to get plugged with debris.

TURBASHED OIL SEPARATOR

TURBASHED OIL SEPARATOR

This item here is an oil separator AND oil reservoir all in one. How it works is the discharge line from the compressors goes to the TOP of the unit  thus a “VORTEX” is created inside and rings out the oil, then separates the oil from the discharge gas and settles to the BOTTOM of the unit then discharge gas exits out the side, it also holds oil in reserve for the compressors as they need oil. This is most predominantly used on HUSSMANN refrigeration racks. 

This is another view of the “TURBASHED” oil seperator and oil filter. These particular types of oil seperators also have numerous site glasses on them to view the oil level.

OIL SEPARATOR FLOAT PLATE

(PLUGGED / DIRTY)

CUTAWAY VIEW OF AN OIL

SEPARATOR

What you see here is an oil float plate. How it works is as the oil is separated from the discharge gas the oil falls to the bottom of the separator onto this float plate and when the oil gets a high enough level the float on the plate will rise and let oil pass through it, then through the oil filter, into the oil reservoir then ultimately back into the compressors where the oil belongs. As you can see this float plate has copious amounts of debris on it thus causing the oil to back up in the separator, when this happens the compressors will starve for oil thus causing them to go off on the oil failure control. NOTE: Always carry an extra oil separator float plate with you I promise you will need it at the most inopportune time (2AM) as an example.  DO NOT ATTEMPT TO CLEAN ALWAYS REPLACE IT!

This here is an example of what the inside of a helical oil separator looks like. There is also another type of oil seperator called an “IMPINGEMENT” type, these particular models have screens inside them. If you ever encounter a situation where the oil level controllers are constantly filling with oil and no matter how many times you adjust them, there is a high probability one/ and or both screens are torn, which in turn will blow oil out the float plate and straight into the oil level controllers, something to consider if you encounter the above mentioned issue.

OCV VALVE

Oil Level Controller

This is an OCV Valve. If the oil pressure in the oil reservoir gets excessive pressure in it, it will open up (SPRING LOADED), and relieve its pressure into the suction line header. Usually RACK systems have an OCV 20, which means 20 PSI differential. 

Notice the flare nut on top of the oil level controller. Behind the flare nut is a little mesh screen that can get plugged with debris. To clean the screen, shut off the line going to it, loosen the flare nut, remove the screen, spray it with electrical contact cleaner, put the screen back in, tighten the flare nut, and open valve back up.

 

 

OIL SEPARATOR FLOAT PLATE

(PLUGGED / DIRTY)

CUTAWAY VIEW OF AN OIL

SEPARATOR

What you see here is an oil float plate. How it works is as the oil is separated from the discharge gas the oil falls to the bottom of the separator onto this float plate and when the oil gets a high enough level the float on the plate will rise and let oil pass through it, then through the oil filter, into the oil reservoir then ultimately back into the compressors where the oil belongs. As you can see this float plate has copious amounts of debris on it thus causing the oil to back up in the separator, when this happens the compressors will starve for oil thus causing them to go off on the oil failure control. NOTE: Always carry an extra oil separator float plate with you I promise you will need it at the most inopportune time (2AM) as an example.  DO NOT ATTEMPT TO CLEAN ALWAYS REPLACE IT!

This here is an example of what the inside of a helical oil separator looks like. There is also another type of oil seperator called an “IMPINGEMENT” type, these particular models have screens inside them. If you ever encounter a situation where the oil level controllers are constantly filling with oil and no matter how many times you adjust them, there is a high probability one/ and or both screens are torn, which in turn will blow oil out the float plate and straight into the oil level controllers, something to consider if you encounter the above mentioned issue.

Oil Resevoir

Oil Resevoir 2

What you see here is an oil resevoir tank, as what has been described earlier within this site this is where the oil is deposited after it (oil) leaves the seperator. Notice on the bottom of the tank there is a service valve to both isolate and check oil pressure, this is important to know because if you are having oil problems, hook your gauges to the port and check the pressure here VS your suction pressure, So for instance if you have 15 PSI suction and 45 PSI at th bottom of the resevoir, then this pressure is sufficient enough to return to the compressor via the oil level controller.

NOTE: Turn service valve in to FRONTSEAT..Turn valve OUT to BACKSEAT. Make sure valve is BACK SEATED BEFORE removing schrader cap or you WILL have a huge oil mess.

Here is a picture of two oil resevoirs. something to take note of is when doing an oil change on a rack is to SHUTOFF the outlet (bottom valve) to trap any existing oil to keep it from going to the compressors, then after the oil change out is complete with the compressors, drain the resevoir by attaching a hose to the fitting (Valve Back Seated) the open the service valve and drain oil into a bucket, once that is done pump in new oil through the same port now when doing so make sure you pump in enough oil to float MINIMUM one ball or slightly past first sight glass.

 

 

OF-303 OIL FILTER

This is the most popular oil filter that is used on rack systems. If you get a call for a compressor OFF and you find it is off on oil failure control and the date is more than ONE year on the oil filter, CHANGE IT OUT. NOTE: T means tap, to check pressure.

Oil Differential Valve

What this valve does is to create a differential of pressure (25psi) for the oil feeding system on rack compressors that have LOW/MEDIUM temperature discharge lines all on one common header. Because the low temperature compressors have a LOWER crankcase pressure and the medium temperature compressors have a HIGHER crankcase pressure this valve will keep the LOW temp compressors from taking all the oil and the medium temp compressors getting nothing, this valve evens it all out so ALL the compressors get equal oil feeding them. NOTE: There is a screen on the inlet of the valve, not uncommon for it to get plugged with debris.

TURBASHED OIL SEPARATOR

This item here is an oil separator AND oil reservoir all in one. How it works is the discharge line from the compressors goes to the TOP of the unit  thus a “VORTEX” is created inside and rings out the oil, then separates the oil from the discharge gas and settles to the BOTTOM of the unit then discharge gas exits out the side, it also holds oil in reserve for the compressors as they need oil. This is most predominantly used on HUSSMANN refrigeration racks. 

TURBASHED OIL SEPARATOR

This is another view of the “TURBASHED” oil seperator and oil filter. These particular types of oil seperators also have numerous site glasses on them to view the oil level.

OIL SEPARATOR FLOAT PLATE

(PLUGGED / DIRTY)

What you see here is an oil float plate. How it works is as the oil is separated from the discharge gas the oil falls to the bottom of the separator onto this float plate and when the oil gets a high enough level the float on the plate will rise and let oil pass through it, then through the oil filter, into the oil reservoir then ultimately back into the compressors where the oil belongs. As you can see this float plate has copious amounts of debris on it thus causing the oil to back up in the separator, when this happens the compressors will starve for oil thus causing them to go off on the oil failure control. NOTE: Always carry an extra oil separator float plate with you I promise you will need it at the most inopportune time (2AM) as an example.  DO NOT ATTEMPT TO CLEAN ALWAYS REPLACE IT!

CUTAWAY VIEW OF AN OIL

SEPARATOR

This here is an example of what the inside of a helical oil separator looks like. There is also another type of oil seperator called an “IMPINGEMENT” type, these particular models have screens inside them. If you ever encounter a situation where the oil level controllers are constantly filling with oil and no matter how many times you adjust them, there is a high probability one/ and or both screens are torn, which in turn will blow oil out the float plate and straight into the oil level controllers, something to consider if you encounter the above mentioned issue.

Oil Resevoir

What you see here is an oil resevoir tank, as what has been described earlier within this site this is where the oil is deposited after it (oil) leaves the seperator. Notice on the bottom of the tank there is a service valve to both isolate and check oil pressure, this is important to know because if you are having oil problems, hook your gauges to the port and check the pressure here VS your suction pressure, So for instance if you have 15 PSI suction and 45 PSI at th bottom of the resevoir, then this pressure is sufficient enough to return to the compressor via the oil level controller.

NOTE: Turn service valve in to FRONTSEAT..Turn valve OUT to BACKSEAT. Make sure valve is BACK SEATED BEFORE removing schrader cap or you WILL have a huge oil mess.

Oil Resevoir 2

Here is a picture of two oil resevoirs. something to take note of is when doing an oil change on a rack is to SHUTOFF the outlet (bottom valve) to trap any existing oil to keep it from going to the compressors, then after the oil change out is complete with the compressors, drain the resevoir by attaching a hose to the fitting (Valve Back Seated) the open the service valve and drain oil into a bucket, once that is done pump in new oil through the same port now when doing so make sure you pump in enough oil to float MINIMUM one ball or slightly past first sight glass.

 

 

What Does the Oil System Do?

The oil comes from the compressors, much like the oil in your car. The compressors need lubrication for the pistons moving up and down inside the cylinder walls. Here’s what happens: As the pistons are moving up and down in the cylinder walls, oil is being pumped via an oil pump throughout the compressor, through the bearings, pistons, and any other moving parts. In doing so, some oil gets past the piston rings and goes through the discharge valves. From there it will go through an oil separator, which separates the oil, and goes to the bottom of the separator. It will go onto a float plate, with a float that will open when there is oil sitting on it, then send the oil through an oil filter to the oil reservoir tank, to a oil level controller, and eventually to the compressor sump. Some refrigeration systems like self contained, one-on-one systems do not have an oil separator. The oil is returned from the suction pressure coming back to the compressor and dropping the oil in. Grocery store RACK refrigeration systems do the same thing as well. They, “RACKS”, use the two methods described above. They also bring oil back back via the suction lines as well as going through a separator, a filter, to an oil tank, and back to the compressors. Let me clarify a few things here. Some one-on-one systems use semi hermetic compressors, (COPELAND and CARLYSLE), like an RTU = Roof TOP UNIT, or it can be located anywhere.  They will sometimes have a small oil separator or an oil level controller, to get oil back inside the compressor. Along with oil coming back through the suction line to the crank case. Another way oil gets back to compressors is what is called “PUSH/PULL” systems. Basically the oil sloshes and migrates between compressors. This is common on HUSSMANN TD systems with open drive compressors.  It should also be mentioned when the oil comes out of the reservoir, to go to the compressors, there will be a “DIFFERENTIAL VALVE”. It kind of looks like a TXV.  Differential is used when one oil line feeds both a rack that has low and medium temp compressors on the same lineup. The valve creates a differential of 25 PSI to feed the oil evenly, otherwise the LOW TEMP rack with its lower suction crankcase pressure would take all the oil, and the medium temp compressors would get nothing. The differential valve creates equal pressure to feed all compressors on the lineup.  

Troubleshooting Oil Failures

How to Test Oil Systems

The troubleshooting of oil failures is not overly tough once you firmly understand how it works. So lets start with you have a compressor off on OFC= Oil Failure Control,lets start with the compressor, so before you start hitting reset buttons and take off, I would suggest you first OHM out the load side of the contactor, and check the contactor as well to make sure it is not pitted. MAKE sure the windings are not Grounded or open first of all, if that checks out good,check the oil level controller, IS THERE OIL VISIBLE IN IT? next check the oil reservoir tank, is there oil in it? if there is, then good, so next check the oil filter, usually a OF303 or whatever oil filter cannister is in series with the oil line. if it is more than a year old, change it, first by shutting off the valve coming OUT of the separator plate, wait approx 10 minutes for the pressure to drop, then shut off the service valve on TOP of the tank,using your service wrench, FRONT seat it all the way, then proceed to slowly crack open the flare nuts on the OF303 Filter..NOTE: MAKE SURE YOU HAVE PLENTY OF RAGS!!!! as there will still be some oil pressure in the filter.Now once it (FILTER) is removed install the new one, now tighten the bottom nut, then to get the air out of it, you can slowly open the valve coming out of the separator, make sure the TOP flare nut is on, but barely loose, once oil comes out of it, then quickly tighten it.. After you have tightened both flares nuts,  on . Then go to the compressor and if it has a “SENTRONIC” Oil switch, on the right lower side of the oil pump on a copeland there is whats called a “TRANSDUCER” it measures the oil pressure as part of the electrical control system, I would suggest at this point you pump the compressor down to “0” PSI by putting your gauges on the discharge side, after gauges are hooked up, shut off the control toggle switch and the BREAKER, the front seat the discharge service , then hook a hose to the rack SUCTION to bleed off the pressure, front seat the SUCTION service valve, make sure compressor is reading “0” psi then use a  crescent wrench to remove the Transducer, once removed spray it liberally with Electrical contact cleaner..NOTE: When re installing make ABSOLUTE sure the the rubber “O” ring is on, or the compressor WILL go off on oil failure..Now since the compressor has no pressure on it, you can also clean the screen on the oil level controller, it is located inside the oil inlet line, spray it clean as well, now at this point its a judgement call as to check the oil pickup screen, if you do decide to do it in the lower left corner of a copeland , there will be a block with either two nuts,or a BIG nut, the small bolts use a 1/2″ socket or the BIG nut uses a 1-7/16″ socket, so drain the oil, remove screen, spray it clean, insert back in..NOTE: The pickup screen sits in a housing, make double sure the slit metal is facing “DOWN” when re inserting..Put all back together, pump in ONE GALLON of either POE or AB150 depending on refrigerant.Double check to make sure every thing is tight that you took apart, then open discharge and suction lines on compressor, open top of tank service valve, open valve coming out of oil separator going to oil filter, then turn on breaker and control toggle switch, and hit “RESET” on sentronic, then put a gauge on the oil “T” tap on top of pump, the one with a hand tightened cap has the schrader and the one that takes a wrench DOES not, so be careful, now check NOP, which is oil pressure minus suction.wait approx 20 minutes to make sure all is good, if it goes off on OFC even after all that you did, check the compressor contactor, if it is pitted, then change it, if problem still persists then you more than likely have a bad SENTRONIC,but before condemning make sure you have CHECKED EVERYTHING..NOP,OIL LEVELS,CONTACTOR.ETC.As they are very expensive, remember you are a SERVICE TECH NOT A PARTS CHANGER!!! Last but not least I will talk about the separator float plate, if all else has failed, and still have oil failure issues, then you will have no choice but to remove the float plate and REPLACE it, make double sure you have one with you..DO NOT JUST SIMPLY CLEAN IT!!! REPLACE IT.. Now to do so you will need to pump down ALL the compressors that are on the discharge header. Do this by front seating all the suction service valves, once thats done, then shut ALL compressors off, both on the control toggle switches and the breakers, hook your hose up to any schrader port on the discharge header, and run it to ANOTHER RACK, Make double sure it is the same refrigerant, shut off ALL ball valves on or near the discharge in and out, then let the other rack pump it down to “0” PSI then get an Aluminum turkey pan from the sales floor, put it underneath, and proceed to remove the float plate, now be prepared for ALOT of oil to come out, and have plenty of rags on hand, remove and replace the float plate..NOTE: Be prepared to shut off ALL the discharge service valves on the compressor if there is only one Ball valve on the discharge header..Once its changed it is a good idea to use your vaccum pump to remove the air from the system so as to not have “NON CONDENSIBLES” in the system like air and moisture..Once thats  done then and the plate is tight, and system evacuated close off your gauges and open ALL the discharge service valves, open the Ball valves..VERY important to not miss any steps,open up suction service valves on on the suction side of the compressors, DOUBLE check to make sure ALL VALVES on the discharge side are OPEN, then turn on breakers, then one at a time turn on control toggle switches.Finally based on how much oil comes back, you may have to actually remove oil from the system especially if people been pumping oil in the system instead of ACTUALLY fixing the problem, or you may have to add oil, just monitor your oil tank reservoir and go from there. Now based on everything thats been done this should cure the Oil failures, later you may have to come back and drain the oil from ALL the compressors and pump in new oil, but thats  big “IF”.. At this point only time will tell.  

Follow these steps on your journey to becoming a Journeyman!

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