Example 6: Cracks Develop In Field Pipes Due To Thermal Expansion And Contraction - Panasonic Urban Multi MX1 Series Manual

Bad Examples and Good Examples in Installation
7.6 Example 6:
contraction
Situation
Refrigerant piping has developed cracks in soldered points and is leaking gas.
Cause
Both ends of the pipe have been tightly fixed in place.
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Starting and stopping the compressor has caused temperature to vary, thus the pipes have expanded and
contracted which places stress on soldered parts.
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Cracks have formed because of repeated expansion and contraction.
Remedial Action
Fit the pipe with a loop as shown in the below drawing.
Main Points
For Your Reference
Expansion (m) = Full length × Coefficient of thermal expansion × Rise in temperature
Coefficient of thermal expansion for copper: 16.5 × 10
Example For a pipe length of 10 m and a rise in temperature of 50°C, expansion reaches 8.2 mm.
76
Cracks develop in field pipes due to thermal expansion and
Take thermal expansion and contraction along the spline into consideration when installing pipe
supports.
PACD011001G2 / PACD011004G3
-6
Urban Multi Inverter "MX1" Series