High discharge temperature

[raviperumal]

we had purchased the scroll compressor from Danfoss. It is worked well for two years.

Now the Head temperature is increasing gradually and trips in temperature.

It gives very high noise also.

The application is chiller plant

Evaporating temp 10'C
Condensing Temp 45'C

What could be the probable cause for this problem?

Kindly help me to understand the issue.

Best regards.
ravi perumal

[cameron.e]

check the condenser eg: fans, brittle condenser,and decrease superheat ,hope it helps.

[frank]

If it's been running fine for 2 years and the discharge pressure is increasing then the problem leads toward a lack of heat rejection.

Check the efficiency of the fans and the cleanliness of the condenser coil - and look for any recent additions of nearby plant or buildings that could be affecting the flow of air over the condenser

[Dimitris]

Based on what you say, I'm afraid the compressor needs to be changed. Usually when a scroll compressor makes that sound and heats up, it means that it has been damaged from lack of lubrication due to working at excessively high pressure and temp, as well as very low superheat (return of liquid.)

[kpntreal]

Have you had a possible recent phase change?
You are aware that the three phase scroll is direstionallly sensitive?

[REEFER-TEK]

I agree with dimtris,

If you hear it make abnormal sounds, the damage is done, this is probably what is causing the high compressor temperature, When you repalced two years ago did you determine why it failed then? Most scrolls require a liquid injection or quench valve in effort to control compreesor temperature. if this valve is not working properly or the sense bulb is not installed and wrapped you will lose a compreesor again.

tHis is just my opinion.

Regards R-T

[Bones74]

I would before you change anything, Check the power and the amp draw. Resistance in the windings and put a voltage monitor on it. Damaged windings cause heat, heat trip units off.

[sohail]

I also agree with dimitris,the compressor oil level must be checked and the condeser for short cycling of the discharge air back to inlet head pressures increase due to choked condenser .

[1torr]

If the discharge temperature is high I would check that the superheat is not too high. If the TEV is not letting enough refrigerant through it can cause high discharge temperature, but then you would see a low suction pressure.

[absolute-zero]

raviperumal,

Did you get it fixed and what was the end story?

Just curious

Regards R-T

[hendry]

raviperumal,
1] u should re-consider the SDT. check with your local weather condiions.

[hendry]

raviperumal,
2] check your condensing equipment & capacity.
3] check cooling vs liquid level.

[kothari]

Hi Ravi,
It is your moral duty to let the forum participants to be informed what you did to resolve the issue.Don't afraid whether you did right or wrong.It can be a learning for others.
Thanks,
Kothri

[D.Evans]

Just a quick thought, I recently went to service a chiller unit with scroll compressors and found one of the four compressors running quite happily, if a little noisy, on only two of the three phases. The problem was traced to the soft start on the unit.

[powell]

I just noticed how old this post was. Nevermind.

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