Brema Icemaker VM900 refrigerant charge

[nike123]

Anybody have any information on what is correct charge by weight for Brema Icemaker VM900

It is 4-5 years old and refrigerant is R404A
Condenser is water cooled!

[nike123]

Anybody?
...?.....

[1mikeefc1]

Stop water going to it and charge until the evap plate is fully frosted back down the suction. Can't give you a weight sorry.

[install monkey]

i searched last night, air cooled,water cooled- tells you everything about the weight of each cube (or trapezoid) but nothing on the gas charge:confused:

Anybody?
...?.....

[nike123]

Do you mean that I stop pump working from beginning of ice making cycle, so that no ice is collected at evaporator at all. And than, to charge to frozen suction pipe just before suction line heat exchanger?
What would that be superheat value than?

Last time, when I charged it by my lucky guess, I got, in such condition at start of cycle, superheat of about 40K and evaporation temperature of -11°C.

http://www.youtube.com/watch?v=IXDX6yDNvy4

[nike123]

By your instruction, that superheat should be about 10K. I am afraid that with such value of superheat at beginning I will end up with lot of liquid refrigerant at end of cycle, since I got at end of cycle, in same situation about 4K superheat at -18°C evaporation.

http://www.youtube.com/watch?v=3vLG89xdy9k
Also, I adjusted evaporator thermostat at -18°C to stop Ice production.
With such adjustment and charge and entering water of 14°C, ice producing cycle lasts between 15 and 18 minutes before defrost operation takes place.

[nike123]

i searched last night, air cooled,water cooled- tells you everything about the weight of each cube (or trapezoid) but nothing on the gas charge:confused:

Now you know how it was for me!:D

[nike123]

By this article:

http://contractingbusiness.com/refrigeration/ice-machine-service-fundamentals

correct superheat (when TXV or AXV) is used is about 1-2K. Therefore, I presume that correct charge with capillary tube as expansion device would be near that value at the end of ice making cycle.
Therefore my charge at last time is slightly undercharged condition.

Am I correct, or wrong in my presumptions?

[nike123]

I just found that simmilar older Scotsman CM855 have these data for charge (of R502):

Low pressure just before harvest 28 psig (-19.4°C).
High pressure 240 psig (42,4°C).
Superheat of TXV is 3-4K.

It looks like that I have been close in my first attempt to charge it correctly without knowing what is factory weight charge. Sadly, I did not measure the weight.