Data Sheet
Table Of Contents
- 1 About this document
 - 2 Safety and disposal
 - 3 Product-specific approvals
 - 4 Product-specific information
 - 5 Use
 - 6 Product description
 - 7 First steps
 - 8 Using the product
 - 9 Smart App
 - 10 Maintenance
 - 11 Technical data
 - 12 Tips and assistance
 - 13 Support
 
8 Using the product 
13 
2 
Take a photo of the QR code of the 
testo Smart App and press 
[Menu/Enter] to confirm. 
- 
The measurement menu is displayed. 
8  Using the product 
8.1  Preparing for measurement 
8.1.1  Operating the valve positioners 
With respect to the refrigerant path, the digital manifold behaves just like a 
conventional four-way manifold (only applies to the testo 557s): The passages 
are opened by opening the valves. The applied pressure is measured with the 
valves closed and the valves opened. 
- 
Open the valve: Turn valve positioner anticlockwise. 
- 
Close the valve: Turn valve positioner clockwise. 
 WARNING 
Valve positioner tightened too tightly. 
•
  Damage to the PTFE seal (1). 
•
  Mechanical deformation of the valve 
piston (2) leading to the PTFE seal (1) 
falling out. 
•
  Damage to the thread of the threaded 
spindle (3) and the valve screw (4). 
Broken valve knob (5). 
Only tighten the valve positioner hand-tight. 
Do not use any tools to tighten the valve 
positioners. 










