| Evaporator Design Compatibility | Confirm that the evaporator matches the water cooler's refrigerant, cooling capacity, operating temperature, dimensions, connection size, and mounting arrangement. | Product drawings, technical data sheets, refrigerant compatibility statement, dimensional drawings, and application guidelines. | All critical parameters should be documented and compatible with the intended cooling system before ordering. | Only general product descriptions are provided; refrigerant type, capacity, or connection details are unavailable. | High |
| Cooling Performance | Review rated cooling capacity, entering-water temperature, outlet-water temperature, ambient conditions, refrigerant condition, and test method. | Performance curves, laboratory test reports, rated-condition tables, and sample test records. | Performance data should identify test conditions and use consistent units such as watts, kilowatts, Celsius, and litres per hour. | Capacity is stated without test conditions, or performance claims are based only on marketing language. | High |
| Material and Corrosion Resistance | Check the materials used for water-contact surfaces, heat-transfer surfaces, tubing, brazed joints, insulation, and protective coatings. | Material declarations, corrosion-resistance specifications, water-quality limitations, and applicable test records. | Materials must be suitable for continuous contact with the intended water type and operating environment. | Material grades are undisclosed, water-contact components are not identified, or corrosion limitations are omitted. | High |
| Manufacturing Quality Control | Verify incoming-material inspection, brazing quality, leak testing, cleanliness control, dimensional inspection, and final performance testing. | Quality-control plan, inspection checklist, sample inspection report, process records, and nonconformity procedure. | Critical production and inspection steps should be documented, repeatable, and traceable to a production batch. | No written inspection process, no batch traceability, or reliance on visual inspection only. | High |
| Leak and Pressure Testing | Determine how the refrigerant circuit and water circuit are tested for leakage and whether test pressure, duration, and acceptance limits are recorded. | Leak-test procedure, pressure-test record, calibrated equipment list, and certificate of conformity. | Each unit or defined production batch should undergo documented testing using calibrated equipment. | Testing is described as optional, records cannot be provided, or acceptance limits are not defined. | High |
| Certifications and Compliance | Check which safety, electrical, pressure, environmental, and material regulations apply to the complete assembly and its intended market. | Applicable conformity declarations, test reports, safety documentation, and regulatory compliance statements. | Documentation should clearly identify the covered product, model range, applicable standards, and issuing organization. | A certificate is shown without product identification, scope, validity information, or supporting test documentation. | High |
| Warranty Coverage | Review warranty duration, covered parts, exclusions, remedy options, start date, labor responsibility, shipping responsibility, and claim requirements. | Written warranty terms, sales contract, warranty claim form, and replacement or repair procedure. | Warranty terms should be specific, written, and consistent with the quotation and purchase contract. | Warranty is offered verbally, exclusions are unusually broad, or the supplier can change terms after shipment. | High |
| Warranty Claim Process | Confirm how a failure is reported, what evidence is required, who performs diagnosis, and how quickly a decision is issued. | Step-by-step claim procedure, response-time commitment, troubleshooting guide, and technical escalation contacts. | The process should define contact channels, required evidence, investigation stages, and expected response times. | No defined claim channel, no response-time commitment, or customer must return defective parts before any technical review. | High |
| Technical Support | Assess support availability for selection, installation, refrigerant charging, troubleshooting, maintenance, and replacement-part identification. | Support policy, technical contact details, installation manual, troubleshooting chart, and service training materials. | Support should be available through documented channels during stated business hours, with escalation for urgent failures. | Sales staff cannot answer technical questions, manuals are incomplete, or all support depends on a single individual. | High |
| Replacement Parts Availability | Check availability of compatible seals, fittings, sensors, insulation, valves, and other serviceable components. | Spare-parts list, part-number system, recommended stock list, lead-time information, and replacement instructions. | Critical replacement parts should have identifiable part numbers and a stated supply period. | Components are not separately identifiable, replacement parts are unavailable, or the supplier requires a complete assembly purchase. | Medium |
| Production Capacity and Lead Time | Verify standard production lead time, peak-season capacity, minimum order quantity, sample availability, and ability to handle repeat orders. | Capacity statement, production schedule, lead-time commitment, sample order terms, and purchase-order confirmation. | Lead times should be stated in writing and include assumptions for approval, materials, testing, and shipping. | Delivery dates are guaranteed before technical approval, or lead times change substantially without notice. | Medium |
| Traceability | Determine whether each product can be linked to a production date, batch, material record, inspection result, and shipping document. | Serial-number policy, batch labels, inspection records, packing list, and certificate of conformity. | The supplier should be able to identify production and inspection information for shipped units. | Products have no batch identification, labels are inconsistent, or records cannot be retrieved after shipment. | High |
| Packaging and Transport Protection | Review protection against impact, moisture, contamination, vibration, tube deformation, and connection damage during transportation. | Packaging specification, packing photographs, handling instructions, and damage-claim procedure. | Fragile connections and heat-transfer surfaces should be protected, sealed, labelled, and secured against movement. | Exposed tubes, weak packaging, no moisture protection, or no documented procedure for transport damage. | Medium |
| Communication and Documentation | Evaluate response accuracy, revision control, quotation clarity, drawing approval, change notification, and language quality. | Quotation, approved drawing, technical specification, revision history, meeting records, and change-control procedure. | Commercial and technical documents should use consistent model numbers, specifications, quantities, and revision dates. | Conflicting specifications, undocumented changes, missing revisions, or reluctance to confirm details in writing. | High |
| Supplier Financial and Operational Stability | Assess business continuity, production location, workforce capability, equipment maintenance, subcontracting controls, and ability to support long-term supply. | Business registration information, facility audit, production capability statement, continuity plan, and customer-reference checks without relying on brand claims. | The supplier should demonstrate stable operations and a practical plan for maintaining quality and supply. | Unclear operating address, frequent changes in contact details, unexplained subcontracting, or inability to provide basic operational information. | High |
| Reference and Sample Verification | Request representative samples and verify fit, dimensions, surface condition, leak tightness, cooling performance, and installation effort. | Sample inspection report, independent test results where needed, approved sample, and documented corrective-action record. | A production-representative sample should pass agreed acceptance tests before volume production begins. | The supplier refuses sampling, provides a non-production sample, or changes materials and design without approval. | High |
| Total Cost of Ownership | Compare purchase price with tooling, testing, packaging, freight, installation, energy impact, spare parts, warranty handling, and expected service life. | Total-cost worksheet, quotation with itemized charges, energy-performance data, maintenance schedule, and warranty-cost assumptions. | Selection should be based on documented lifecycle cost rather than unit price alone. | Very low price is offered with unclear material specifications, omitted testing, limited warranty, or high replacement risk. | Medium |
| Final Supplier Scorecard | Use a consistent scoring system covering technical fit, quality, service, warranty, delivery, compliance, and total cost. | Completed supplier questionnaire, evidence register, audit report, approved sample record, and corrective-action log. | Approve suppliers only when critical requirements are supported by verifiable evidence and unresolved high-risk issues have corrective actions. | Supplier selection is based solely on price, personal relationships, attractive brochures, or unverified claims. | High |