liquid receiver must have a sight glass ?

[bluecool]

Do all refrigerant units with liquid receivers have a sight glass? What is the proceedure for checking charge, during low ambient? If subcooling is useless for checking charge with receiver units, is it because witout a sight glass you would probably overcharge.

[jpsmith1cm]

I've seen receivers with sight glasses in them, receivers with gauge indicators on them showing level as a percentage of capacity.

The PDFs that I posted in the other thread are very valuable if you take the time to read and understand them.


http://sporlanonline.com/90-198.htm

http://sporlanonline.com/90-30-1.htm

These will help you with low ambient charging.

With a small, conventional unit, there is no easy way to check the charge.

[bluecool]

Thanks for your reply. I see my past logic on this subject was wrong. Yours were right -on.

[Mkgjr77]

One way to check the receiver if there is no sight glass is to heat the receiver with a map gas from bottom to top and then slide your finger from the bottom to top until you feel a change in heat. Liquid present in the tank absorbs the heat and gas will not as much thereby creating a temp difference where the level of liquid in the tank stops.

[jpsmith1cm]

One way to check the receiver if there is no sight glass is to heat the receiver with a map gas from bottom to top and then slide your finger from the bottom to top until you feel a change in heat. Liquid present in the tank absorbs the heat and gas will not as much thereby creating a temp difference where the level of liquid in the tank stops.

Good method, IF you have a benchmark.

Without a benchmark, it only gives you a level measurement.

With systems that you work on regularly, it is a simple matter to log levels and other conditions and you can track these things.

[Mkgjr77]

If you are trying to establish a level, this is simple one way to do so. .

[fireye-63]

Well the way to do it is to feel teh temp on the line going...

[Mkgjr77]

I disagree. What is the line temp on the leaving liquid line going to tell you??

That there is subcooling,,,,that has no bearing on the liquid level present in the receiver tank..

If you believe that the liquid line has flash gas this does not have to be caused by a low liquid level in the tank,,,,it could be caused by a restricted drier..