TESTO 557 User manual

testo 557 Digital Manifold
with Bluetooth/App
Quick Start Guide
Temperature port on each side
2 line, backlit LCD display
Control keys
Pressure zeroing
Arrow keys
Escape
3 x 1/4” SAE connections
Show Min/Max/Mean values
Valve knobs
measurement mode. Please make sure to repeat step 2 to turn the
Tfac back to ON before starting normal testing again.
Vacuum / Evacuation
1. Insert the external vaccuum probe into the top
socket. (Pic. 16).
2. Turn on the testo 557
3. Press the [Mode] button twice to get to the
vacuum /evacuation mode (Pic. 17).
4. Attach the external vacuum probe to the system.
5. Start the evacuation.
Warranty
The testo 557 has a two year warranty. If registered, the warranty is extended to 5 years.
Pic. 17
5/8” SAE evacuation port
Leak Test
The temperature compensated leak test is used to indicate leaks in
an AC/R or heat pump system.
1. P lug in the temperature probe into the high side of the
instrument.
2. P ress the set button 6 times to reach the Tfac setting. Press the
UP arrow to cycle this setting to OFF. Press SET to select this setting
3. Z ero the pressure sensors.
4. Connect the testo 557 to the system.
5. P ress the [Mode] button once to get to the leak test mode
(Pic. 14).
6. N ow press the [R, Start/Stop] button to start the test. (Pic. 15).
7. T he test duration depends on the system size.
8. P ress [R, Start/Stop] again to stop the test.
9. T he results will be displayed.
10. Press the [Mode] button twice to return to the normal
Pic. 15
Pic. 14
Power On/Off
Backlight
Pic. 16
The testo 557 now comes standard with Bluetooth.
1. First, turn on the testo Refrigeration App on your smart
device.
2. Once the app is running, turn on the testo 557.
3. Press and hold the UP and DOWN arrow simultaneously to
activate Bluetooth.
4. The Bluetooth icon will flash to the left of the battery display
icon and remain on once bluetooth is activated.
5. The app will now show your 557 as an available device.
(Pic 18)
6. Select your instrument in the app to pair your
557.
Bluetooth Activation
Pic. 18

Changing the batteries
Testo 557 uses 4x 1.5 V, AA batteries.To replace
the batteries please follow these few steps
below:
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).
Backlight
Testo 557 has a backlight to im-
prove viewing. Press the backlight
[k] button to turn the backlight
on. Press it once again to turn the
backlight off.
Pressure zeroing
Please zero the pressure sensors every time before you use
the testo 557.
1. Loosen the hose connections
2. Open the valve knobs to confirm that no
pressure is in the manifold
3. Press the [p=0] button
The sensors are now zeroed and ready for measurement.
Pic. 7
Pic. 6
Pic. 5
Pic. 4
Pic. 3
Pic. 2
Pic. 1
Superheat / Subcooling
Pic. 13
Pic. 12
Pic. 11
Pic. 10
The testo 557 calculates superheat and subcooling in real time.
1. Connect the temperature probes to the testo 557.
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
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).
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.
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.
Pic. 8
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.
Pic. 9