TESTO 557 - Tips and assistance; Questions and answers; Measurement parameters

8 Tips and assistance
23
8 Tips and assistance
8.1. Questions and answers
Question Possible causes/solution
flashes
Batteries are almost empty.
> Change batteries.
The instrument switches
off automatically.
Residual capacity of the batteries is too
low.
> Change batteries.
uuuu lights up instead of
the parameter display
The permissible measuring range has
been undershot.
> Keep to the permitted measuring
range.
oooo lights up instead of
the parameter display
The permissible measuring range has
been exceeded.
> Keep to the permitted measuring
range.
8.2. Measurement parameters
Name Description
bar, °C psi, °F
Δtoh
SH
Superheating, evaporation pressure
Δtcu SC Subcooling, condensation pressure
to Ev Refrigerant evaporation temperature
tc Co Refrigerant condensation temperature
toh T1 Measured temperature, evaporation
tcu T2 Measured temperature, condensation