06D oil pumpin out

[duelfuel]

Hey all..
I have an 06D compressor on a carrier heat pump. The oil in the compressor keeps pumping out and circulating through the system.The unit is not flooding and the insertion heater is good.
No matter how long the compressor runs the oil just keeps circulating through the system. If you leave your charging hose on the suction service valve for 10 minutes then remove it, you get a good blast of foamy oil. The suction pressure is 55 to 60 psi with a varying superheat of 14 to 20 deg at the compressor.
There is an identical carrier next to this unit with the same suction line length,size, rise etc. Two years ago i serviced this unit and the sight glass had oil, now you cant get any oil in the glass, even after adding.
Anyone have an idea whats pumping the oil out of the compressor and whats the soulution besides replacment?

DuelFuel

[genesis]

what is the liquid line temp about 6 inchs from the compressor

[sonc]

LOL

[matt8085]

Blow-by

[duelfuel]

The liquid line is not 6 inches from the compressor.Unless your refering to the oil in the line. LOL As i said its NOT flooding.

[genesis]

LoL you are absolutly right. Was finishing off a 6 pack reading posts around midnight last night. What I ment to say is what is the temp of the discharge line coming out of the compressor.At about 180 degrees I have seen the oil thin out and start to break down and it wont return back to the compressor. It will tend to collect in the condensor coil to the point when it finally returns it blocks the liquid line filter dryer. And what we figured out was the crummy condensor coil design was trapping lint from the cotton woods in the center of the coil and the coil looks perfectly clean. This caused my guys to under charge the units and over heat the compressors. We found this by replacing a coil and taking a saz zal and cutting a cross section out of the coil. The blocked coil was creating a false reading on the gauges and giving you the minimum super heat reading you were looking for.

[duelfuel]

Yea genesis, those cottonwoods are terrible on condenser coils. I've seen what you describe on Trane and American standard RTU's. They are sensitive to dirty condensers and will clog a drier and toast a compressor quick.
This 06D has a clean condenser and oil is continually flowing through the system. It seems to also be the cause of the TXV hunting. I just expected that if it was blow-by of the compressor rings i would have a high crank case pressure. The compressors suction pressure running unloaded is around 55 psig. with a sightly fluctuating superheat.
Ive got a compressor to replace it with, just wanted to figure out if something else is to blame.

[x-wrenchturner]

Originally posted by duelfuel
The compressors suction pressure running unloaded is around 55 psig. with a sightly fluctuating superheat.
Ive got a compressor to replace it with, just wanted to figure out if something else is to blame.

What is the typical load on the compressor like?
If it runs unloaded most of the time, you have your problem.

[747ken]

I'm still learning about these compressors. I have a couple of Carrier training books on the 06Ds, and here's what they say about your problem:

Oil is not returning to the compressor for the following reasons:

1. Low refrigerant velocity or short cycling - due to low refrigerant charge or low heat load (poor airflow?). Low velocity suction gas doesn't have enough velocity to return oil to the compressor. Oil can become trapped in the evaporator. Check for low suction pressure.

2. Excessive compressor unloading.

3. Plugged accumulator oil return holes.

4. Oil is separated from the suction gas in the motor
housing. A check valve and venting system is used
to move the oil in the housing into the oil sump.
If the valve is faulty, oil will remain in the housing
causing excessive oil in the refrigerant.

Hope this helps, bro.

[747ken]

Originally posted by x-wrenchturner


What is the typical load on the compressor like?
If it runs unloaded most of the time, you have your problem. [/B]

hmmm...I'm new to these 06ds. How can you tell if it's unloaded?

Is that determined by suction press, or current draw? Any other way to tell?

[duelfuel]

The 06D has 1 electric unloader. The coil is energized and the compressor amps are low ( 30amps at 208).
Air flow in this system is not excessively low. The evaps are 25+ years old. ( Cheap A&% dont want to pay for new ones)
X this compresor is getting oil return, just not staying in the sump, sump pressure is 55 psig. Yes it runs mostly unloaded. The evap. and condensor are at the same level.

I looked on carlyle's site and the 06d doesnt show a check valve.Will look closer. If it does , your talking a PIA tear down. Grrrr...

[747ken]

Originally posted by duelfuel


I looked on carlyle's site and the 06d doesnt show a check valve.Will look closer. If it does , your talking a PIA tear down. Grrrr...

I'm looking at a Carrier training manual from 1999.
In it they say "In the 06D compressor, a check valve and orifice assembly are installed in the partition just below the oil level." Then they show a diagram of it located near the sump, below the crank.

But it's a training book, not a service manual. Perhaps they don't use the check valve anymore or the book is being too general.

Ok, a dumb question from me...how can you tell if it uses an electric unloader? Are there visible wires going to the unloaders?

[duelfuel]

747 your right, there is a check valve. i Over looked it. It could very well be the problem. When i leave my hose on the suction service port it fills with oil in about 5 min. or less with the compressor running. It sounds logical the check valve is stuck. Thanks bro.
The unloader is a small solinoid bolted to one of the compressor heads. It has 2 wires to it. they also make pressure controled unloaders for it. you turn it to load or unload at a selected suction pressure. Each unloader unloads 2 cylinders of 6 on the compressor. There by reducing capacity and raising the suction pressure. Carrier has recommended pressures to load and unload. Low suction is obviously bad.
Hope you get to work on 06d's they are work horses!