rivering sight glass

[joe magee]

I recently started up a walkin freezer box. Receiver at 50%. temp in box is fine. How come the sight glass does not clear? 2 ton condensing unit 404a refrigerant suction @ 13 psi discharge at 200 psi no head master.Unit on top of box in a 70 ambient no restictions . This seems to fool a lot of techs They always want to clear the glass without torching the receiver ending up with an over charge.

[chillin out]

I think it's something to do with the way it is piped. Liquid line oversized? or just the fact that the pipe is going straight down to the txv.

Just a thought.

Chillin

[joe magee]

possibly. The company I work for has a large engineering department and they can't give me a good answer. Oh well. We also design and build racks for many of the large supermarket chains.
Cheers

[Andy]

I recently started up a walkin freezer box. Receiver at 50%. temp in box is fine. How come the sight glass does not clear? 2 ton condensing unit 404a refrigerant suction @ 13 psi discharge at 200 psi no head master.Unit on top of box in a 70 ambient no restictions . This seems to fool a lot of techs They always want to clear the glass without torching the receiver ending up with an over charge.

flashing in the sightglass indicates a lack of subcooling, this maybe from and undercharge OR it is a restrictive liquid line causing a drop in pressure, flashing off the liquid partially to gas.

Alternatively the sightglass maybe too close to the expansion valve, showing the every opening of the valve

The techs should charge to a known weight or the subcooling off the condenser

Kind Regards Andy

[Pooh]

I have had this sympton when a insufficiently sized receiver was fitted to a system the tubulance of the refrigerant entering the rceiver was causing bubbles in the outlet of the receiver showing in the sight glass. Fitted a larger receiver and the problem went away, took a bit of sorting out though.

Ian

[hem057]

I remember reading too that with the 400 series refrigerants that the sight glass may not clear, due to the different components seperating and therefore a little vapor pressure shows up in the sight glass, therefore the danger of overcharging trying to clear the sight glass.