TESTO 550i - Using the testo 550 i; Measurement Preparation and Valve Operation

8 Using the product
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8 Using the product
8.1 Preparing for measurement
8.1.1 Operating the valve positioners
WARNING
Risk of injury caused by refrigerant that is at
high pressure, hot, cold, or
poisonous!
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Wear protective goggles and safety gloves.
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Before applying pressure to the measuring instrument: Always fasten the
measuring instrument on the suspension hook to prevent it from falling down
(danger of breakage)
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Before each measurement, check the refrigerant hoses are intact and
connected properly. Do not use any tools to connect the hoses; only tighten
hoses hand-tight (max. torque 5.0Nm/3.7ft*lb).
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Comply with the permissible measuring range (-1 to 60 bar/-14.7 to 870
psi).
Pay particular attention to this in systems with R744 refrigerant, since these
are frequently operated with higher pressures.
The digital manifold behaves like a conventional three-way manifold with regard
to the refrigerant path: The passages are opened by opening the valves. The
applied pressure is measured with the valves closed and the valves opened.
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Open the valve: Turn valve positioner counterclockwise.
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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.