Mitsubishi Electric PURY-HP144, Service Handbook

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[1-3 Working with Refrigerant Piping ]
HWE18220_GB
chapter 1 -
7
1 Check Before Servicing
1-3 Working with Refrigerant Piping
1-3-1 Pipe Brazing
No changes have been made in the brazing procedures. Perform brazing with special care to keep foreign objects (such as oxide
scale, water, and dust) out of the refrigerant system.
Example: Inside the brazed connection
1. Items to be strictly observed
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Do not conduct refrigerant piping work outdoors if raining.
Œ
Use inert gas during brazing.
Œ
Use a brazing material (BCuP-3) that requires no flux when brazing between copper pipes or between a copper pipe and
copper coupling.
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If installed refrigerant pipes are not immediately connected to the equipment, then braze and seal both ends.
2. Reasons
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The new refrigerating machine oil is 10 times as hygroscopic as the conventional oil and is more likely to cause unit failure if
water infiltrates into the system.
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Flux generally contains chloride. Residual flux in the refrigerant circuit will cause sludge to form.
3. Notes
Do not use commercially available antioxidants because they may cause the pipes to corrode or refrigerating machine oil to
deteriorate.
Use of no inert gas during brazing Use of inert gas during brazing