- Question Title: alup combi 2 15 hp with dryer - rotation direction error
- Asked by: Guest
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- Answers: 1
I purchased this compressor used (2005 model) not knowing if it works or not.
When i powered it up,it will start for 2-3 seconds then shut down.it throws a fault code # 7 (rotation direction). there is an arrow embossed on housing indicating direction. the compressor is spinning in the correct direction.just to be on safe side i momentarily tried other direction, same code (#7).
I manually pushed the contacts for compressor motor maybe 4-5 seconds,the compressor seems to build internal pressure. The bigger ball or check valve at air inlet is closed and pressurized air releases from small opening outboard of this ball.
I do not have the unit piped to a receiver yet. I can not detect any air coming from the outlet pipe. There seems to be a blockage somewhere in the system.
What would cause the air control to throw a directional code? is there an internal pressure or flow sensor that could be bad? as you can probably tell i know very little about rotary screw compressors. Any help you could give me will be appreciated.
Answers & Replies
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Hi,
It seems that the compressor is running in the right direction, but that for some reason, it doesn't detect that correctly.
Most of the time with compressors that check for rotation direction (some compressors don't), this is done by a device called a "phase monitor relay". This check the rotational field of the incoming 2-phase power supply. Sometimes they only check the direction, sometimes also the voltages across the phases (for extra protection).
See if you have such a device installed in your compressor.
About the inlet valve: yes, it is normal that it is closed at startup. Compressors always (or should) start up in 'unloaded' condition. After starting up and warm-up period, they can be put in 'loaded' condition (inlet valve opens). The escaping compressed air is also normal.
Good luck and let me know the outcome and if you have any more questions..