Discharge superheat

[stevo4546]

Hi guys can you confirm this is correct as I am doubting myself

discharge superheat
1 x discharge pressure & check with comparator what temperature it is
2 x measure actual discharge temp
3 x difference between 2 give s you discharge superheat

r407c chiller @ 100%
discharge pressure 16.5 bar = 40C
discharge temp 64C
discharge superheat 24C ??????

is this correct

cheers guys

[RANGER1]

Yes you are correct

[stevo4546]

Thanks mate

superheat & sub cooling I am ok but was doubting myself with dsh

is a 20C diff normal

high discharge superheat short of gas ?
low discharge superheat over charged ?

[RANGER1]

Each type of refrigerant is different as to discharge temperature.
20 deg sounds ok to me but have you checked suction superheat at evaporator?
If it was a screw you need minimum 15 deg C to drive refrigerant out of oil for good lubrication.

[stevo4546]

Superheat 6C & sub cooling 9C
chiller operating fine just was not sure about discharge superheat

thanks again

[RANGER1]

To me it's fine, as superheat perfect, not much else you can do.
What type of compressor is it.

[stevo4546]

Hitachi screws mate

[RANGER1]

Hitachi screws mate

No no problem then

[RANGER1]

Forgot to ask oil temperature of screw & how it is cooled, as that can also influence discharge temperature (although yours still sounds ok)

oil il temp should be approx 15 deg C higher than SDT & discharge temp a bit higher than oil temp.