Anybody help with atlas copco dryers

[paul441]

Hi guys
I am new to fridge game and have been in my current job for 2 months,its mainly working on atlas copco dryers but i must admit im finding it hard to understand and fix problems and was hoping someone could give me a bit of advice,for example i had a GA 160 compressor with integeral dryer ,it was showing 14 0c dewpoint and i know it should be about 3-5 anyway im not sure what to look at ,like what does hot bypass do also it had soleniod which was clicking ,and exspasion valve how do i know if this has gone, also understanding pressures.dont want to sound totally incompetent but just trying to keep hold of a job. cheers lads:confused:

[Peter_1]

Coincidentally, I repaired today 2 dryers at the Belgium Navy.

Haven't they give you some sort of lessons at Atlas Copco?
In the 1st place, you must comply to the F-gas regulations which states that you must be certified before you may put a wrench on these units. That's the first thing you must try to get.

Bypass is to create an artificial load to the compressor so that TE stays above 0°C at partial load. Was the SV in the refrigerant circuit or outside the unit?

Detecting how a TEV has gone, if charge is correct and you SH isn't despites normal load, then probably your TEV is gone

These units need some basic education to work on, so I think you better follow first some lessons.

[paul441]

Hi
I do have 2078 safe handling,but i only went on a 2 wk course to gain that andto be honest i didnt learn a great deal , i know i need 2079 before july 2011.also what do the sh sv te mean. cheers for the help
Sh: superheat
SV solenoid valve

[glenn1340]

What`s the temperature of the air leaving the aftercooler? If its very high that will seriously affect the dew point. I don`t know how your`e
measuring the dew point but if it`s by the cabinet indicator I`d ignore it as they can be unreliable. Use your gauges and camparitor. TEVs rarely give trouble and it`s the last thing to adjust. I`ve not had problems with the hot gas valve going out of adjustment by the amount to give a 14c DP (most usually by 5c or so)
As to the soleniod valve, it could be the condensate drain. Depending on the age of the Compressor it may be fitted with an electronic level sensing drain, if they develop a fault they often go into a self cleaning mode which results in the solenoid valve clicking.

[paul441]

The dp is showing on the elektronikon and is fluxuating at 12c to 15c which is way to high isnt it.
cheers

[glenn1340]

I`m in the yard tomorrow I`ll have a look in our manuals to see where the probes fitted. I`m not sure if on the Atlas compressors the dew point sensor is on the air out pipe or in the evaporator itself. If it`s possible to easily remove it you could insert a hand held one in the pocket to check the actual evaporator temp.

[Peter_1]

The 'dewpoint sensor' is on the heat exchanger under the isolation.
It's not a dewpoint sensor but a simple thermometer.