After a blower and several air knives have been installed, commissioning must show that every required knife works in each normal production mode. Record the agreed test condition, measure air delivery at defined points, check the control sequence and confirm the actual drying or blow-off result. A statement that a blower can supply a certain number of knives is not an acceptance result.
This checklist is for post-installation verification and handover. It does not calculate the blower duty, select a model or teach how to balance branches. Use the approved design calculation and project acceptance criteria as the test basis; if either is missing, record the gap rather than inventing a pass limit.
Confirm the As-Installed Test Basis
Before running a test, collect the accepted system drawing, knife identification list, intended operating modes and available design or supplier submittals. Check that each installed knife can be matched to its branch, control command and process area. Record the as-installed slot setting, valve position and measurement point where these are part of the accepted design.
The acceptance basis should state what useful result is required for each mode: the product condition, line speed, coverage and any approved pressure, airflow or outlet-velocity limits. Different knives may serve different purposes; do not impose one identical reading on every outlet without a project requirement.
If the design duty or acceptance criteria have not been agreed, stop short of declaring the system accepted. The team can still collect observations, but a pass/fail decision needs an established basis.
Check Readiness Before Energizing
Follow the site’s approved safety and startup procedure. Confirm that guards, electrical connections, pipe supports, filters, flexible connections and air-knife mounts have been inspected by the responsible personnel. Check for obvious loose hardware, disconnected branches and blocked outlets before using measurement results to judge performance.
Record the instrument and measurement locations so later readings can be repeated. A pressure reading taken beside a turbulent fitting should not silently be compared with a design value specified for another location. Record filter condition and the ambient or product conditions that materially affect the test.
Build a Mode-by-Mode Test Matrix
List every normal production configuration: the active air knives, commanded blower setting, product or process step, expected line speed and the agreed result. Include the highest-demand and lowest-demand normal modes and any transition that the control logic permits. Do not assume that a machine with several installed knives runs all of them at once.
The matrix is a **test coverage record**, not a method for summing knife airflow or choosing blower capacity. If a proposed combination is impossible because of interlocks, note that control evidence. If a transition can briefly open an additional branch, include it in the checks where relevant to the approved operating sequence.
Verify Air Delivery at Each Active Knife
Run each test mode under stable, representative conditions. At defined points, record the blower command and status, main-header pressure and branch pressure where measurement provisions exist. Measure total or branch airflow only with an appropriate method and repeatable location. Record outlet-velocity readings across the useful length of every active knife where that is part of the acceptance basis.
Do not rely on a single reading at the center of one knife. A remote knife or one end of a long slot may be weak while the blower outlet appears satisfactory. Note the active branches, gap and valve positions with every set of readings so a later comparison describes the same configuration.
Measurement confirms delivered air; it does not by itself prove that the product is dry or clean enough. Observe the actual process result across the required coverage area at the agreed production speed.
Check Control, Interlocks and Alarms
For each normal mode, confirm that the intended knives and blower command are active before the product reaches the process zone. Where the approved control design includes speed changes, valve sequencing, run confirmation or alarms, test their expected behavior and record the outcome.
Check relevant transitions as well as steady states. Opening or closing a branch can change pressure and useful air at the remaining knives. If a commanded mode does not reach its expected state or an alarm fails to appear under an approved test condition, document the fault and repeat the affected test after correction. Do not invent alarm thresholds or bypass safety devices to complete a checklist.
Record the Process Acceptance Result
Use representative product and the agreed line speed to judge drying or blow-off performance for each active configuration. Inspect the full width or all relevant surfaces, including areas served by remote branches. Record the observation method, result and any product or process condition that could explain variation.
Where power, temperature, noise or vibration are part of the approved commissioning requirements, record them at stable operation. These observations support handover and future comparison; they should not be turned into an unsupported energy-saving or service-life claim.
Classify Each Mode as Pass, Fail or Not Yet Verified
Compare readings and process results with the project-defined criteria. Mark a mode Pass only when its required checks are completed and the process result is acceptable. Mark Fail when an agreed criterion is not met. Use Not yet verified when a criterion, instrument reading, representative product or test condition is missing.
A useful record includes:
| Record field | Entry to capture for each tested mode |
|---|---|
| Configuration | Active knife IDs, product, line speed and blower/control setting |
| Approved basis | Criterion and its document or responsible owner |
| Measurement | Location, method, instrument, reading and relevant conditions |
| Process result | Observed coverage and drying or blow-off outcome |
| Decision | Pass, Fail or Not yet verified, with reason |
| Follow-up | Corrective owner, retest date/result and sign-off when complete |
Keep raw readings where possible, not only averages. An average can hide a weak end of a slot or a failing branch.
Escalate a Failed Result Without Hiding the Evidence
If one knife is weak, record which knife, mode, measurement location and process area failed. Inspect for an evident obstruction, incorrect gap, disconnected hose or unintended valve position under the approved troubleshooting procedure. If all knives are weak, record the common-path readings and blower status. These observations help identify who should investigate; they are not a branch-balancing procedure.
Do not simply increase blower speed or throttle a stronger branch and mark the mode accepted. If the installed system needs air-distribution correction, use a separately reviewed balancing method. If the required blower duty itself appears wrong, return to the design calculation. Retest every mode affected by a correction, because one adjustment can change other branches.
Prepare the Handover Record
Preserve the final mode matrix, accepted settings, measurement locations, raw readings, process observations, alarm checks, open issues and retest history. Identify the person or team responsible for any remaining action and the agreed sign-off status. These records establish a baseline for maintenance without claiming that every future product or condition has been validated.
Where Towwind Technology or another supplier is asked for technical support, send the relevant as-installed drawing, accepted design basis, failed mode, measurement locations, readings and observed process result. That evidence is more useful than reporting only that “one of the air knives is weak.”
Commissioning Questions
Is a system accepted when every knife blows air?
No. Each required configuration must also meet its agreed air-delivery and process-result criteria at representative operating conditions.
What if the pressure reading is acceptable but one product area remains wet?
Record the location and compare outlet performance and process conditions for the affected knife. Pressure at one point does not prove useful coverage along the whole slot.
Can an untested operating mode be marked as passed?
No. Mark it Not yet verified until the required test conditions and evidence are available, or document an approved exception through the project’s own process.