Commissioning is the step that turns an installed vapor recovery unit into a working one. It is not only a matter of switching on and confirming that the unit runs; the value lies in establishing a documented baseline, so that a change in behaviour six months later can be compared against something measured rather than remembered. A structured sequence also catches installation mistakes while the installers are still on site.
Before the first start
Walk the installation against the drawing. Confirm mechanical completion, that pipework is supported and connected as designed, that electrical terminations are tight and correctly labelled, and that all isolation valves are in the position the start-up procedure requires. Check that the vapor line is clear and that nothing has been left inside the pipework during construction.
Functional checks in sequence
- Verify instrument readings against local indication before starting any rotating equipment;
- Confirm alarm and trip settings against the design values, and record each one;
- Start auxiliary systems, such as cooling where fitted, and confirm they reach their normal operating condition;
- Start the main unit and observe it through a full cycle, watching pressures, temperatures and cycle timing;
- Introduce a realistic vapor load and observe the response, noting how long stabilisation takes;
- Test the safety functions one at a time, including the shutdown path, and confirm the correct response.
Baseline readings worth recording
| Reading | When to take it | Why it is worth keeping |
|---|---|---|
| Suction pressure and discharge pressure | Under steady load | The reference for spotting gradual change |
| Cycle time or running pattern | Over a defined period | Shows whether the unit is cycling more often than expected |
| Condensate volume | Over a known operating period | A practical indicator of how the unit is performing |
| Supply and ambient temperature | At the same time as the other readings | Explains much of the seasonal variation seen later |
| Alarm and trip settings | At handover | Confirms what the unit is actually set to, not what was assumed |
Handover records
Provide the settings actually applied, the baseline readings, the test results for the safety functions and a note of any outstanding item. Outstanding items listed openly at handover are far easier to close out than the same items discovered later without a record.
Frequently asked questions
How long should commissioning take?
It depends on the unit and on how much of the site is already available for testing. The sequence is more important than the duration: each check should be completed and recorded before the next one begins, so that a problem can be attributed to a specific step.
Can commissioning be done without a realistic vapor load?
Partly. Mechanical and electrical checks can be completed, but the response of the unit to load and its cycle behaviour are best confirmed with a realistic load. Where that is not possible at first, record what was tested and plan a follow-up under normal operating conditions.
What should be done if a reading differs from the design value?
Record the difference, investigate whether it is an instrument issue or a genuine process condition, and resolve it before handover where possible. A reading explained as normal without investigation often turns into an early service call.
Luoyang Wohong Petrochemical Equipment Co., Ltd. supplies double-wall composite fuel piping, fittings and electrofusion accessories for gas station and fuel depot projects. Contact us for pipeline layout review and product selection support.