Oilchange, how to ?

[Challenger]

Hi, I need to change oil on a Bitzer provision compressor. Model 4G-20.2Y-40P

Can anyone in here please check if this is the right way to do it. If not please correct me..

Thanks.........

1. Close suction valve and wait untill compressor stops.

2. Turn off compressor

3. Close outlet valve from compressor.

4. Open valve marked C on attached picture.

5. Drain old oil through C

6. Fill oil through C with a handpump.

7. Cloce valve C

8. Connect vacuum pump to compressor outlet valve.

9. Turn on pump and pump out moisture in compressor.

10. After this open suction valve and start compressor.

Can it be done like this ?

What is A and B on the picture ?

[install monkey]

b is normally crankcase pressure
a is oil pressure outlet port- normally 15psi above crankcase pressure
if ur pumping down the comp, then you will still have gas in ur heads, if this is the case then u have to vac on the suction side only, then you can vac the oil in on C with a 1/4 line into your new oil
saves pumping it in.
dont forget to energise crankcase heaters for 24 hrs - whilst vaccing prior to starting

[Challenger]

Sorry, I am not working on compressors very often, so i am a little confused.

Could you please make a step by step how to do list.

I am not going to do this oilchange alone, but my boss (i am a apprentice) wants me to make a how to do list before we starts the job.

He knows how to change the oil, but he wants me to find out myself.

So if you also could explain how to do it I would be very happy.

Thanks....

[install monkey]

1. Close suction valve and wait untill compressor stops.

2. Turn off compressor

3. Close outlet valve from compressor.

4. Open valve marked C on attached picture.

5. Drain old oil through C

6. Fill oil through C with a handpump.
connect vac pump to low pressure side of the compressor, connect a gaugeline or 1/4 pipe with a flare nut on port C- run your vac pump and this will create a vacuum on the compressor body which will suck the oil into the compressor-saves on pumping

7. Cloce valve C

8. Connect vacuum pump to compressor outlet valve.

connect to the low pressure side only
9. Turn on pump and pump out moisture in compressor.
if you remove the fuses/shut the breaker off for the compressor and power up the unit- the crankcase heater will warm the compressor sump

10. After this open suction valve and start compressor.

Can it be done like this ?

What is A and B on the picture ?

[The Viking]

Challenger,
Just adding to / editing your list;
0.1 Check for leaks.
0.5 Connect gauges.
1 Shut liquid line valve or solenoid and wait for the system to pump itself down.
1.5 Ensure crankcase/suction pressure is 0 or below
3 Close compressor's suction and discharge valves.
3.5 Release the refrigerant trapped in the compressor's discharge side in to suction line.
5. Drain old oil through C, using OFN to push it if necessary.
6. Connect vacc pump to compressor at as many points as reasonable possible, ensuring both high and low sides are covered.
7. Start vacc pump.
8. Suck oil in through "C"
9. When the oil is at the correct level shut valve "C" and continue vacuuming until desired level of vacuum is achieved.
10. Open suction, discharge and liquid line valves.
11. Reinstate the system.
12. Check for leaks.
13. Clean up.

[monkey spanners]

Make a note of the oil level on the sightglass before you drain it then you can fill it back to the same level.

Re check oil level once it has been running, seem to remember some compressors have one way valve in sump to allow oil to drain from the motor side to the sump but prevent oil going in the other direction.

Or you could measure what comes out and put the same back in, still check level though after some run time.

[PaulZ]

Hi Challenger
You might also want to add in the following before you drain the oil,
1A. Shut the oil return (if this compressor has one)
2A. Turn off crankcase heater and tag.
2B. Isolate compressor and tag out / lock out
Regards
Paul

[mikeref]

This might get a little messy, so fit a line onto "C" valve outlet before draining oil.
Make sure your container capacity is way bigger than the amount of oil you are removing.

Some compressors here only have 1/4 or 1/8th BSP bungs. Lesson learnt when there is 10 PSI pressure remaining in the crank case.:eek:

[Challenger]

Thank you...... You are all the best !!!!!!

[Challenger]

96459646

Hi again
A few more questions.

On the suction valve on the compressor there is no fitting I can connect vacuum pump to. It has a blind fitting only. How can I remove this blind and connect another fitting ?
My guess is that this blind (marked H on picture) would be in open position if the suction valve is closed.
And H would be closed if suction valve is open.
If this is correct then would it be possible to remove the H plug when suction valve is open, and mound another fitting instead of the blind.

On discharge valve this "I" fitting is open when the discharge valve is closed.
I know this because I tryed to unscrew the cap on "I" fitting while the discharge valve was open, and I could hear/feel gas coming out from "I".

Are these suction/discharge valves working as 3-way valves with these "H" and "I" fittings ?

Thanks again......

[Challenger]

Sorry the work open should be changed to Closed. Like this.....


On discharge valve this "I" fitting is open when the discharge valve is closed.
I know this because I tryed to unscrew the cap on "I" fitting while the discharge valve was CLOSED, and I could hear/feel gas coming out from "I".

[The Viking]

Yes to pretty much all you said in the last 2 posts.

:cool:

.

[Challenger]

Ok I just wanted to be sure it is safe to open up this blind plug while suction valve is open and compressor is running.

Thanks....

[mikeref]

Ok I just wanted to be sure it is safe to open up this blind plug while suction valve is open and compressor is running.

Thanks....
Back seat your valves then remove the plug and install fitting for gauge line.