Originally Posted by
ZeroTolerance
Can someone please explain to me the operation of the purge unit. Still kind of new with chillers. I get what the purge's purpose is, but still have a few unanswered questions.
Does the Filter Core house just water? Or water and refrigerant?
It houses refrigerant. However, if that refrigerant has water in it, it will absorb that water from the refrigerant.
How does one know whether there is water in it? I see the sightglass, but don't know if that's liquid refer or water.
What style purge do you have? If sightglass is on the purge tank, the water will float on top of the liquid refrigerant-you may be able to see it. If sightglass is in liquid return line-moisture indicator in the glass will indicate the presence of water.
How does one go about draining the water in the purge unit?
Crack open the 1/4 inch service valve on the the purge tank while the chiller is running with a positive condenser pressure-it has a diptube that extends down to the liquid level. I have rarely used this myself. If there is water, change the drier.
Why does my liquid temp stay at 70deg F and my suction continue to steadily drop until there is a bit of frost on the compressor suction side?
"Liquid Temp" is saturated temperature of the chiller refrigerant in the chiller condenser (or possibly chiller evaporator). Purge compressor suction temps are a function of load on the purge tank (which functions as purge cicuit's evaporator); air will displace the load and result in low suction temps, which should initiate a pumpout cycle.
Should the Filter core container be pressurized, because when I press the depressor on it, all that comes out is an alcohol watery looking substance with no pressure behind it? I have to physically pull out the schrader valve in order for it to stop leaking the watery substance.
[COLOR="Red"]The filter drier is at chiller condenser pressure. There may be a slight difference, but not enough to see on your gauges[COLOR="Red"]
I know the purge unit is supposed to pump air/water out of the chiller. If it is pumping air out, will the sightglass bubble?
It pumps out air, not water. Sometimes bubbles will be seen due to the relatively warm temp of the sightglass housing "boiling" the refrigerant; when pumping out, the pressure in the tank is slightly lowered.
How do I know if the purge unit is pumping out either air or water?