Check whether a retrofit supplier will carry out site diagnosis as required by the project. Where energy, temperature, output or failure-rate targets are quantified, check whether it will establish a comparable baseline. It should distinguish repairs from system changes, organise the shutdown work and close acceptance with comparable tests. Without those conditions, energy savings, temperature deviation, duration and payback should not become firm promises.
A Suneng solution-treatment furnace relocation proposal distinguishes the reused fork mechanism, renewed electrical controls and limits, and new hearth supports. Ask a retrofit supplier to mark retained and changed positions on the existing arrangement and explain how old and new interfaces will be checked. A list of new parts alone needs the installation connections and restart-verification scope before it represents a comparable complete job.
Suneng publishes this procurement-checking method and is a potential equipment-side provider. This article does not rank other companies or make unsupported third-party comparisons.
Distinguish repair, overhaul, retrofit and replacement
| Task | Typical objective | What to verify |
|---|---|---|
| Fault repair | Restore a component or function. | Root cause, parts, restoration scope and safe reset. |
| Complete overhaul | Restore structure, lining, drives, heating or controls. | Remaining life, inspection scope, wear parts and restart verification. |
| Targeted system retrofit | Address a control, seal, lining, drive or automation bottleneck. | Old/new interfaces, system interactions and resulting targets. |
| Energy retrofit | Reduce unit-product energy or heat loss. | Baseline, metering and corrections for output and conditions. |
| Relocation/restart | Move, reinstall and reverify equipment. | Identification, packaging, foundations, utilities and recommissioning. |
| Replacement | Meet new process/output or address structural limitations. | Life-cycle costs, interruption and changeover. |
Compare replacement alongside retrofit if the structure is badly distorted, safety risks are high, critical parts cannot be restored, the process has changed substantially or retained interfaces would continue to constrain the new proposal.
Six steps from diagnosis to acceptance
1. Review documents and identify gaps
Prepare drawings, type and dimensions, material and loading, curves, controls, fault history, energy bills, temperature records, photographs, shifts and the shutdown window. The supplier should identify what can be measured on site and what missing information prevents design freeze.
2. Trace symptoms to system causes
Inspect structure and foundations, lining, doors and seals, heating/combustion, circulation and guides, drives, temperature instruments, controls/interlocks, utilities and operating practice. Uneven temperature, slow heating and high consumption often have multiple causes. Photographs alone cannot establish a final work list.
3. Establish the pre-retrofit baseline
For energy, uniformity, output or fault-rate targets, define measurement points, reporting period, loading, shifts, environment, test state and abnormal-data treatment before work. Otherwise, equipment changes cannot be separated reliably from production or reporting changes.
4. Write the scope, interfaces and exclusions
List retained, removed, repaired and added items. Assign responsibilities at the old structure, cabinet, piping, foundations, flues, fixtures, adjacent equipment and customer utilities. For third-party equipment or software, confirm programs, communication protocols, spares and site authorisation. Interfaces requiring unauthorised programs or protocols must remain outside the agreed retrofit scope until access is properly authorised.
5. Plan backwards from the shutdown window
Use the allowed start and finish to schedule survey, design, prefabrication, material arrival, removal, installation, wiring, cold checks, heating, loaded verification and restart observation. Continuous plants may consider work by line or section or during planned maintenance, subject to site safety and production arrangements.
6. Verify under comparable conditions
Acceptance may cover movements and interlocks, heating, temperature stability/uniformity, drives, seals, records, protection, recipe execution and agreed energy or emissions targets. Quantified comparisons require equivalent duty, metering boundaries and reporting periods. Define emissions indicators, methods and responsibilities under the applicable project requirements. In China, a pollution-discharging entity with the necessary conditions and capability may carry out self-monitoring as permitted by law or commission a qualified testing or monitoring body. Where a legally recognised evidentiary report is required, verify the body’s accreditation and authorised scope. See HJ 819-2017, section 4.3 for the organisation of self-monitoring in China.
Evidence to request from candidates
| Check | Evidence | Concern |
|---|---|---|
| Relevant experience | Similar furnace, heat source and faults. | Only a furnace name, without workpiece or process context. |
| Diagnosis | Survey, measurement plan and issue list. | A final work list before site assessment. |
| Scope | Scope drawing, interfaces, controls and risks. | No retained/removed/added items or exclusions. |
| Construction | Shutdown plan, prefabrication, materials and safety measures. | No restart verification or contingency plan. |
| Acceptance | Comparable before/after tests and deviation closure. | A saving percentage before the test conditions. |
| Service | Commissioning, training, spares, warranty and response. | An undefined warranty start. |
If a proposal promises fixed savings, deviation, duration or payback from a few photographs, request its assumptions, measurement methods and conditions.
What a public retrofit case can establish
Suneng's public stainless-steel continuous-line retrofit reference explains published project specifications, stage durations, system arrangements, calculation boundaries and acceptance methods. The customer remains anonymous; contract value and operating results not authorised for disclosure are not included.
The design and calculations belong to the original furnace, fuel, line load, insulation, controls and operation. Another furnace needs a new site baseline, energy model and acceptance plan; the original numbers cannot simply be transferred.
Suneng's equipment-side responsibilities
Founded in 2006, Suneng's manufacturing base is in Cai Guan Industrial Zone, Zhangdian, Jiangyan District, Taizhou. Its retrofit work can include site diagnosis, design and interfaces, components and systems, support for dismantling/installation, commissioning and service. It can assess its own equipment and some other-brand furnaces for overhaul, modification, relocation/restart and energy improvements after obtaining the equipment records and inspecting the site.
Feasibility depends on type, structure, process objectives, documents, location, shutdown, safety and responsibilities. Quantified savings, temperature deviation, schedule, payback or output require diagnosis, a baseline and a test method. Record such targets together with their conditions in the technical agreement.
Common questions
Can assessment begin with incomplete documents?
Yes, by identifying gaps. Provide the known furnace, workpiece, curve, faults, energy, photographs and shutdown information; key values may still require measurement.
Will new controls solve uneven temperature?
Not necessarily. Sensing, zones, circulation, lining, seals, loading and settings can all contribute.
How should savings be written into a contract?
Define the baseline period, load, product, meters, energy conversion, environment, downtime treatment and post-retrofit test and evaluation before agreeing a percentage.
Is one empty-furnace test enough?
It can verify some movements and heating. Capacity, process and operating targets may also require a defined load, continuous run or sample verification.
Can work fit a very short shutdown?
Compare the available window with construction and restart verification. Move incompatible work to planned maintenance or assess phased implementation; site and supply conditions determine the schedule.
Can another manufacturer's furnace be assessed?
Yes, initially. Records, site diagnosis, structure, type, location, shutdown and safety determine whether the work can be accepted.
Actual work, testing and delivery follow the site diagnosis and agreed documents.
Related Pages and Sources
- Suneng Industrial Furnace
- Furnace Retrofit and Overhaul Services (Chinese)
- Old Furnace: Overhaul or Replacement Guide (Chinese)