R407C Superheat, subcool.
Hi all.
I'm probably going to shoot myself in both feet for asking this question - what is the expected SH and SC figures for R407C, please? (in *C)
If I'm right, the SH for R407C should be in the order of 6 to 8C*, but SC?
I have tried an internet search, but seem to bang my head against several brick walls - or is it that the walls are banging at my head?
There is a lot if info for R22 etc, but so much of it is in *F.
The reason for the question relates to a swimming pool heat pump.
There is no discharge service valve, but a schraeder valve just before the drier.
Suction Press 4.8 bar
Liquid Line Press 21.5 bar
Suction Temp 15*C
Discharge Temp 46*C (the most consistent, very difficult access)
Liquid Line Temp 27*C
Evap Air On 21.4*C
Evap Air Off 17.8*C
Pool Water In 24*C
Pool Water Out 27*C
I had to remove front cover to get these figures, and let the machine settle for at least 10 mins, after refitting front panel (affects evap air flow).
From this, I reckon SH to be 7.8C*, and SC to be -24.7C*?
I'm aware there are other variables to be collected, water flow volume etc., but this was a snapshot info collection because the evaporator was heavily iced the day previously (ambient in excess of 20*C).
Any help would be appreciated
Many thanks for sticking with the rambling!
Graham
Re: R407C Superheat, subcool.
Liquid line pressure 21.5 bar (gauge) corresponds to 51°C saturated temp.
The subcooling in your case is 51-liquid line temp 27°C = 24K
Generally speaking SH and SC have no fixed figures.
I would suggest a min SH greater than the glide of R407c and smaller than 12K.
And I would suggest a SC at least 2K greater than the corresponding depression of the saturated temperature caused by the pressure drop of the liquid line.
