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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.:)
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:) :)
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
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.Quote:
Originally Posted by joe magee
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:)
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
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.