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. 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.

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.

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.

3GS MINERAL OIL

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.

OCV ON TOP OF OIL RESEVOIR TANK

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.

DIFFERENTIAL GAUGE

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.

CHECKING NET OIL PRESSURE

(NOP)

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 an approximation) 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.

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 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.

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 Level Controller

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 2

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

Oil Resevoir 2

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.  

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.