View Full Version : Sub cooling and superheat

08-11-2011, 09:07 AM
Hi all how do you go about measuring sub cooling and superheated on a vrv/vrf system for making sure there is enough refrigerant in the system.
Need to do this for leak testing for f gas.
Any help would be great

08-11-2011, 10:28 AM

There are 2 easy ways on a VRV.


Go into the controler and find the information from that.


Fit gauges and compare pressures to temperatures.

Discharge pressure = condensing temperature, then measure with a probe the
liquid out of the cond and take that value away from the gauge temp to show

On the suction side you will struggle due to there being more than one evap,
but the principle is similar.

Measure gauge pressure and compare it to suction temp and the differance is superheat.



08-11-2011, 10:18 PM
Sub cooling and superheat in VRV/VRF systems in general are difficult to monitor as there are two many variants when the systems are running especially if they are heat recovery systems.You would need to put systems in the test modes and then check your TDs on all your indoor units.
If its for your F gas then you still need to carry out your leak test as is required.No short cuts !

install monkey
08-11-2011, 10:36 PM
daikin vrv3 have containment check where it will run at different modes/frequency to determine any difference in performance