frost in expansion valve

[mrfrost]

gentlemen...I am working in a ship with 4 cold chambers. I have been noticing frost build up on TXVs of meat and fish chambers. These rooms are kept at -25 degrees centigrade. The system uses R404a as refrigerants. Is frosting in this case normal or will I start looking for causes of the problem?

[sedgy]

mrfrost, at-25c you would expect a bit of frost, dose the frost build up? have you seen the system go onto de- frost
let us know what happenes ,

[mrfrost]

Thanks for the reply sedgy. The frost builds up but seems to decrease during defrosting. Defrosting is set at about 30minutes every 12 hours.

[sedgy]

mrfrost, can you make a note of suc, pressure , discharge pressure, supperheat? and which type of de-frost please?

[philfridge]

Defrosting is set at about 30minutes every 12 hours.

Hi there, You could see if this helps ,Set room temp at -21 as colder than this is not needed for meat or fish. Also defrost period is incorrect, I would sugest you set these rooms up for 4 defrosts per 24 hours with a 30 minute duration. Try this and report back with results

[chillin out]

Dirty expansion valve filters.

Chillin

[mrfrost]

Thanks for your replies...

sedgy, yes I will provide you data later...

chillin out, i have already cleaned the TXV filters...

philfridge, yes I will try that.

I appreciate your help...

[mrfrost]

Hi guys

The system is ok as of now. Seems that philfridge got it. Thanks to you all.

[lowcool]

ya better tip his scales then

[subb-zero]

Hey i agree with chillin out check the filters on in the expansion valve, also what suction pressure are you getting?