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B.B.
19-10-2005, 03:21 PM
First post on R.E. Can anyone tell me the method of returning the capacity slide valve to minimum position on a Hallscrew 2024 should the compressor trip during running in a loaded position.
I am thinking along the lines of the unload capacity solenoid being of the normally open type. If anyone can add to this, thanks.:)

derfriguy
24-04-2007, 10:33 AM
i have seen two normally open solenoid valves used in conjunction with the load /unload valve. Can't describe the configuration exactly off the top of my head but think it aims to open the unload side of the capacity cylinder to the suction line upstream of the suction check valve when the compressor stops for any reason.

Andy
24-04-2007, 11:35 PM
First post on R.E. Can anyone tell me the method of returning the capacity slide valve to minimum position on a Hallscrew 2024 should the compressor trip during running in a loaded position.
I am thinking along the lines of the unload capacity solenoid being of the normally open type. If anyone can add to this, thanks.:)

Hi BB:)

Halls usE a larger surface area on the return piston side, so energise the unload solinoide and the slide will float home. Better still use the pre lub pump and the manual unload button.
Or remove the refrigerant and disconnect the loading pipes and use compressed air to push the slide back if it sticks.
A sticking slide should be investigated by a good old pull it down and looK for the wear.

Kind Regards Andy :)

hendry
15-12-2007, 07:02 PM
Hi guys,

in any screw compressor, it is recommended that a startup is performed at no load point.

How is it done?
1] system with oil pump >> run oil pump 1st & start unload solenoid valve until preset timer trigger or the 0% limit switch activates.

2] system without oil pump >> manufacturer will give you a preset time or you can check physically the motor ampere at which it is lowest.

How we know?
We write PLC program for screw compressor in our country which to date has beat some of the supplier who is still using PCB ctrl.

guapo
16-12-2007, 07:09 AM
First post on R.E. Can anyone tell me the method of returning the capacity slide valve to minimum position on a Hallscrew 2024 should the compressor trip during running in a loaded position.
I am thinking along the lines of the unload capacity solenoid being of the normally open type. If anyone can add to this, thanks.:)

Hi B.B.,

Just press the oil pump button and the slide valve will come back to minimum. Once your capacity indicator or LVDT is not in minimum position during stand by, your unload coil is energized.
Also check the LVDT calibration.

hendry
16-12-2007, 09:12 AM
does your unit comes with fridgewatch of Hall screw?

if not, then you should try the method i mentioned earlier.

wael
13-11-2010, 05:28 PM
please , i need catalouge of hallscrew compressors hs2020 & if any one know its cooling capacity please inform me