short of gas symtoms?

[philjd26]

hi, just running this by you guys<, an engineer i work with was telling me that icing back to the compressor are signs of lack of refrigerant on an r22 split wit a setpoint of 18, was i right in disagreing with him by saying that if there was a lack of refrigerant you would be getting abnormal tempartures after expansion and posssibly get ice on parts of the heat exchanger and then in turn get high superheat! too me icing up too comp would indicate no airflow, dirty coils etc also i heard someone a mention a high latent heat load can cause this problem... can someone give me there opinions?

cheers

[Brian_UK]

Start with your thoughts first.

[chillin out]

was i right in disagreing with him

Yep, you were.

Everything you said is pretty much true.

Chillin

[lana]

Hi there,

Here is the lack of refrigerant symptoms:

1- Low LP
2- Low HP
3- High super-heat
4- Low sub-cooling
5- Bubbles in the sight glass

Sub-cooling is the best indication.

When suction line is frosted then this could be from :

1- The suction gas temperature is below 0°C. Means the suction pressure is low, for whatever reason.
2- Liquid flood back.

Lack of refrigerant is very simple to diagnose.

Cheers

[philjd26]

thanks for replys lads, any ideas about a high latent heat load? cant really get my head around it....from what take from it is if the there humidity to remove from the air it takes so much watts of cooling to change condition of air and struggles to take down temp, any ideas on how this would cause icing of suction?

rgrds

[mohamed khamis]

No....When the system is operated under high latent load compared with the sensible the moisture drain off is only increased and no possibilities for frost to be existent on the evaporator coil unless the system is much overdesigned and the evaporatung temperature is below zero and it is very scarce to occur.

Regards

[bruisermac]

high latent heat load is the amount of moisture the load contains. on container reefer cargo certain loads are brutal for this ie. herring roe and certain frozen fish. both are packaged in a brine solution which is a water and salt solution. herring roe is -10c and will consistantly ice up evap coils which blocks air flow hence ices up compressors etc... frozen fish -23c does the exact same thing. this product makes it difficult to reach setpoint sometimes defrosting every 45 mins to 1 hour to achieve any results. alot of nuisance service calls but otherwise easy money!!