TESTO 557 Quick Start Manual page 2

Pic. 1 Pic. 2
Pic. 3
Pic. 4
Pic. 5
Pic. 6
Pic. 7
Changing the batteries
Testo 557 uses 4x 1.5 V, AA batteries.To replace
the batteries please follow these few steps
below:
1. Fold out the hook (Pic. 1).
2. Grab the clip and squeeze it together to
remove the cap (Pic. 2).
3. Insert/Change the batteries. Observe the
polarity.
Power ON / OFF
1. Connect the pipe clamp probes to the
testo 557 prior to powering it up.
2. Press the power button [ ] to turn the
testo 557 on.
3. All display segments will light up (2 s.)
4. The measurement view will then be
displayed.
5. Press the power button to turn the
testo 557 off.
Select the refrigerant
1. Press the [R, Start/Stop] button so
you can choose the required
refrigerant
(Pic. 3).
2. Use the arrow keys [pq] to scroll
through the choices.
3. Press the [R, Start/Stop] button to set
the chosen refrigerant.
Set the Units / Mode
1. Press the [Set] button once to
get to temperature units menu
(Pic. 2)
2. Choose the required units with
the arrow keys.
3. Press the [Set] button for the
second time to be able to choose
the pressure units (Pic. 5).
4. Choose the desired units with
the arrow keys.
5. Press the [Set] button for the
third time so you can select
absolute or relative pressure
(Pic. 6).
6. Press the [Set] button four
times, so you can set the vacuum
unit (Pic. 7).
Pic. 8
Backlight
Pressure zeroing
Testo 557 has a backlight to im-
Please zero the pressure sensors every time before you use
prove viewing. Press the backlight
the testo 557.
[k] button to turn the backlight
on. Press it once again to turn the 1.
2.
backlight off.
3.
The sensors are now zeroed and ready for measurement
Pic. 9
Superheat / Subcooling
The testo 557 calculates superheat and subcooling in real time.
1. Connect the temperature probes to the testo 557.
Pic. 10
2. Switch on the testo 557.
3. Connect the testo 557 and the pipe clamp probes to
the air conditioning, refrigeration or heat pump
system
4. You will now see the calculated evaporation and
condensation temperature (Ev and Co) as well as the
Pic. 11
system pressures at the bottom of the display (Pic. 9).
5. Press the UP-arrow once to see the temperature
difference (Pic. 10)
6. Press the UP-arrow again to see the real time
superheating and sub-cooling (SH and SC) (Pic. 11).
7. Press the UP-arrow again to see the real time
measured line temperature (T1 and T2) (Pic. 12).
Pic. 12
8. Press the UP-arrow a final time to get to back to the
calculated evaporation and condensation temperature.
You can also use the DOWN-arrow to switch between
the displays but the order will be reversed.
Pic. 13
8. Press the [Set] button five times to select
the AC/R [ ], heat pump [ ], or Auto [
(pic 8). Auto mode senses if the low pressure
side is 15 psi higher than the high pressure
side, and will automatically reverse the display
of the high / low side pressures.
Loosen the hose connections
Open the valve knobs to confirm that no
pressure is in the manifold
Press the [p=0] button
]
.