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Sight gas

The Sight Gas component gives you a view inside the system to see how much liquid compared to gas exists where the component is situated. 

Refrigeration systems sometimes have a sight glass at the condenser outlet. The inlet of the sight glass is supplied by refrigerant from the liquid line and at this point not much vapour should be evident.

If bubbles or flash gas are seen it shows that maybe there is a problem in the system due to the fact mainly liquid should be seen at this point.  This is especially necessary on a TXV metering system. 

So the site gas is a great tool to give an invaluable insight into the inner workings of the system and troubleshooting.