Unloader

[Abe]

Would anyone care to offer some spiel on unloaders, the ones fitted on the head part of compressors

I see them installed on the compressors I work on, but Ive never had to commission one, ie: set the pressure switch settings, etc

I know they kick in on start up, apart from that Im green on this subject

Ok........who said I was an ace tech anyway? But Im getting there............. ( with your guys help!!)

[reggie]

Most internal unloaders in the cylinder head are operated by oil pressure which lifts the suction valve ring plate from its seat via lift pins. Once the valve is seated then the cylinder can seal. If the valve is lifted off its seat then the refrigerant pressure is pumped straight back into the suction line hence no compression.

The oil pressure which is responsible for the seating of the valve is generally controlled by an actuator which can be adjusted
by the tension of its internal spring. This in turn moves a floating piston which fires the oil to each individual unloader in stages.

So the compressor is regulated by back pressure. The higher the suction pressure the more unloaders activated by the actuator.

[iceman007]

Would anyone care to offer some spiel on unloaders, the ones fitted on the head part of compressors

I see them installed on the compressors I work on, but Ive never had to commission one, ie: set the pressure switch settings, etc

I know they kick in on start up, apart from that Im green on this subject

Ok........who said I was an ace tech anyway? But Im getting there............. ( with your guys help!!)

Usually you will set the unloaders with a pressure switch if they are suction actuated rather than electric, or sometimes have an adjustment screw on the compressor (the Trane 8 cylinder recips have one) You would set the cut in and differential so that your compressor loads at a certain pressure and then unloads as the suction pressure and load reduce. You don't want to flood them and on the other hand you don't want to have them cycling the unloaders on and off every 2 seconds.

[mbc]

Another unloading system in starting time is in discharge pipe you have check valve . before that they put one solenoid valve and goes to suction line . In starting time fist it come this solenoid valve one to
Equalize pressure in low and high side of compressor about 5- 10 sec then compressor comes on in star
After if goes to delta solenoid goes off.

[mbc]

Another unloading system in starting time is in discharge pipe you have check valve . before that they put one solenoid valve and goes to suction line . In starting time first it come this solenoid valve one to
Equalize pressure in low and high side of compressor about 5- 10 sec then compressor comes on in star it is on ,After if goes to delta solenoid goes off

[goshen]

Would anyone care to offer some spiel on unloaders, the ones fitted on the head part of compressors

I see them installed on the compressors I work on, but Ive never had to commission one, ie: set the pressure switch settings, etc

I know they kick in on start up, apart from that Im green on this subject

Ok........who said I was an ace tech anyway? But Im getting there............. ( with your guys help!!)

hi there mai me at gill@gosheneng.co.il
i have scanned info on loaders ,trane and carrier
& copeland, would be happy to send .

[NoNickName]

Rest this thread in piece. 7 years old. Must be a record.