UEi Test Instruments SSM1 - Manual (Page 3)

What is Super Heat / Sub Cool?
Refrigerant superheat refers to the rise in
temperature of vapor after the refrigerant has com-
pletely changed from a liquid to a gas. The dew point
(temperature at measured pressure where all of the
liquid evaporates) is determined by properties of the
refrigerant and measuring the pressure. When com-
paring this to the measured pipe temperature of the
return line will determine superheat. The SSM1 will
calculate this value directly and update in real time.
Use superheat on fixed orifice or capillary systems.
Refrigerant subcooling refers to the drop in
temperature of liquid refrigerant after it has com-
pletely changed from a gas to a liquid. The boiling
point (temperature at measured pressure where the
liquid stops boiling and starts to further cool) is deter-
mined by properties of the refrigerant and measuring
pressure. When comparing this to the measured pipe
temperature at the exit of the condenser determines
subcooling. The SSM1 will calculate this value
directly, and update in real time. Use Subcooling
on TXV systems, as they are designed to maintain a
constant superheat.
2.