New Install With an Unlabelled Recovery Cylinder and a Tight Deadline
A technician is commissioning a new 8 kW split system using R-32. The install is complete and the system has been pressure-tested with nitrogen and evacuated. The technician needs to add the factory charge plus a line-length adjustment, and the only R-32 cylinder on site is a recovery cylinder with no label and a valve that does not match the technician's charging hose. The van also carries a labelled virgin R-32 charging cylinder, but it is nearly empty. The customer's handover is scheduled for the same afternoon, and the technician has a recovery machine and an identifier but no adaptor for the mismatched valve.
1. Decide whether the unlabelled cylinder can be used to charge the new system and justify the decision.
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The unlabelled cylinder must not be used to charge the new system. A cylinder with no label has no verified contents, and a recovery cylinder by design may hold recovered refrigerant of uncertain quality. Charging a new R-32 system from it would put an unidentified substance into a circuit whose safety classification and pressure ratings depend on R-32 being the only refrigerant present. R-32 is mildly flammable, so the charge composition is a safety matter, not only a performance one.
The correct source is the labelled virgin R-32 charging cylinder, even if it is nearly empty. If it does not hold enough to complete the charge, the technician must obtain more virgin R-32 rather than substitute from the unlabelled cylinder. The identifier can confirm what the unlabelled cylinder contains, but confirmation of identity alone does not establish purity or that the cylinder is suitable for charging; a recovery cylinder is not a charging cylinder. The handover deadline does not change this.
2. The labelled cylinder holds only part of the required charge. Explain how the technician should proceed and what must be recorded.
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The technician should charge what the labelled cylinder can supply, then stop and obtain the balance of virgin R-32 before completing and handing over. Charging part of the charge and running the system to meet the deadline would leave the system undercharged, with low suction pressure and possible compressor damage, and the handover would be based on a system that does not meet its specification. The customer should be told the handover moves to when the correct refrigerant is available.
The record should capture the factory charge, the line-length adjustment, the mass actually charged from the labelled cylinder, and the mass outstanding. The unlabelled cylinder should be set aside, labelled as unidentified, and returned to the depot for identification or disposal rather than left on site where it could be mistaken for stock. The mismatched valve and missing adaptor should be noted so the van stock is corrected. These records make the incomplete charge traceable and prevent a later technician from assuming the system is fully charged.
3. The customer offers to accept the system as-is if the technician will 'just top it up from the other cylinder'. Give the technician's response and the reasoning.
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The technician should decline. Accepting the offer would mean charging a new R-32 system from an unlabelled recovery cylinder, which puts an unidentified and possibly impure refrigerant into a mildly flammable circuit. The system's performance, its pressure-temperature relationship, and its safety classification all assume R-32 only, so the technician could not verify the charge or certify the handover. The customer's acceptance does not transfer the technician's responsibility.
The response should be practical rather than simply a refusal: explain that the system is complete and evacuated, that only the correct virgin refrigerant is missing, and that a short delay now avoids a contaminated system that would need recovery, flushing, and recharging later. Offer a firm date for the balance of the charge and confirm the handover checks that will be done then. The unlabelled cylinder should be removed from site so the question does not recur.