Friedrich Kuhl KCS12B10A Service Manual page 79

R-32 SEALED SYSTEM REPAIR
General Information
Warning:
No ignition sources: No person carrying out work in relation to a REFRIGERATING SYSTEM which involves exposing any pipe work shall use any sources
of ignition in such a manner that it may lead to the risk of fire or explosion. All possible ignition sources, including cigarette smoking, should be kept
sufficiently far away from the site of installation, repairing, removing and disposal, during which refrigerant can possibly be released to the surrounding
space. Prior to work taking place, the area around the equipment is to be surveyed to make sure that there are no flammable hazards or ignition risks.
Ventilated Area: Ensure that the area is in the open or that it is adequately ventilated before accessing the refrigerant in the system or conducting any hot
work. A degree of ventilation shall continue during the period that the work is carried out. The ventilation should safely disperse any released refrigerant
away from the work area or external to building envelope.
During Repairs To Sealed Components: All power must be removed from the equipment being worked on prior to any removal of sealed covers, etc. If
it is absolutely necessary to have an electrical supply to equipment during servicing, then a constant leak detector shall be located at the most critical
point to warn of a potentially hazardous situation.
Checks And Repairs To Electrical Devices:
• Repair and maintenance to electrical components shall include initial safety checks and component inspection procedures. If a fault exists that could
compromise safety, then no electrical supply shall be connected to the circuit until it is satisfactorily dealt with. If the fault cannot be corrected
remove power supply to unit. DO NOT OPERATE.
Initial safety checks shall include:
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•That capacitors are discharged: this shall be done in a safe manner to avoid possibility of sparking;
•That no live electrical components and wiring are exposed while charging, recovering or purging the system;
•Verify unit is properly grounded.
• Particular attention shall be paid to the following to ensure that by working on electrical components, the casing is not altered in such a way that the
level of protection is affected. This shall include damage to cables, excessive number of connections, terminals not made to original specification,
damage to seals, incorrect fitting of glands, etc.
Ensure that the apparatus is mounted securely.
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Ensure that seals or sealing materials have not degraded to the point that they no longer serve the purpose of preventing the ingress of flammable
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atmospheres. Replacement parts shall be in accordance with the manufacturer's specifications.
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The following is a list of important considerations when working with R-32 equipment:
R-32 pressure is similar to R-410A and approximately 60% higher than R-22 pressure.
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R-32 cylinders must not be allowed to exceed 125˚F, they may leak or rupture.
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R-32 must never be pressurized with a mixture of compressed air, it may become MORE flammable.
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• Servicing equipment and components must be specifically designed for use with R-32 and dedicated to prevent contamination.
• Manifold sets must be equipped with gauges capable of reading 750 psig (high side) and 200 psig (low side), with a 500-psig low-side retard.
• Gauge hoses must have a minimum 750-psig service pressure rating.
Recovery cylinders must have a minimum service pressure rating of 400 psig, (DOT 4BA400 and DOT BW400 approved cylinders).
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POE (Polyol-Ester) lubricants must be used with R-32 equipment.
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To prevent moisture absorption and lubricant contamination, do not leave the refrigeration system open to the atmosphere for extended periods
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of time.
• If unit refrigerant is low, recover the refrigerant, evacuate, and recharge unit to nameplate amount.
• If there is any amount of refrigerant in the system charge from the low side.
Always charge by liquid inverted.
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NOTE: Sealed system repairs to cool-only models require the installation of a liquid line drier.
NOTE: Sealed system repairs to models with a heat pump require the installation of a suction side drier.
Verify with tool manufacturers that all tools used during this repair are non-sparking and can be used with A2L Refrigerants.
No halide torches for leak testing.
Refrigerant monitors or detectors must be used to detect refrigerant in the work area.
• R-32 A2L Refrigerant Recovery System.
• Vacuum Pump rated for A2L refrigerant (capable of 300 microns or less vacuum.)
Nitrogen bottle with purging and pressurizing capabilities up to 550 psi.
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Oxy/ Acetylene torch or similar equipment utilized for brazing.
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Non-Sparking (Not Halide)Electronic Leak Detector rated for detecting A2L refrigerant.
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• Digital refrigerant scale
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