Signs & diagnostics
A cleaner-looking canopy is easy to deliver and easy to be fooled by. A proper extraction clean reaches the filters, plenum, duct and fan and proves it with photos and readings. Knowing what real evidence looks like is how you tell a TR19 Grease clean from a quick wipe of the visible steel.
The short answer
A cleaner-looking canopy is easy to deliver and easy to be fooled by. A proper extraction clean reaches the filters, plenum, duct and fan and proves it with photos and readings. Knowing what real evidence looks like is how you tell a TR19 Grease clean from a quick wipe of the visible steel.
The detail
The clearest tell is evidence. A proper TR19 Grease clean produces before and after photographs taken from matching positions, micron readings from set points, a summary of what was done, notes on any areas that could not be reached, and a hygiene certificate naming the technician, date and location. A clean with no paperwork is a clean you cannot rely on.
The second tell is scope. A common corner-cut is cleaning only the visible canopy and filters while leaving the ductwork behind them untouched. Since the duct is where most of the fire load and airflow restriction sits, a clean that stops at the stainless has missed the point - and usually will not have the interior photos to prove otherwise.
The third is access. Cleaning the hidden runs requires access panels roughly every two metres. If a job was done without opening or fitting them, large stretches of duct cannot have been reached, and a good report will say so honestly rather than imply the whole system was cleaned.
The fourth is the numbers. Post-clean, deposits should verify below 50 microns against the TR19 threshold. A report that gives you actual readings against the 200 micron mean and 500 micron point is doing the science; one that offers only a shiny photo of the canopy is selling the appearance of a clean.
What it means for you
If you suspect a poor clean, the symptoms tell on it quickly - grease returning at the lip, smells, weak capture or a labouring fan soon after a supposed clean all suggest the system was not actually restored. A clean that holds should push those signs away, not leave them in place.
An independent inspection settles it. A borescope look into the duct and fresh WFTT or DTT readings show whether the interior was really cleaned or only the visible parts. Recognition schemes like the Vent Hygiene Register exist precisely because the quality of a clean is otherwise hard to see.
Phoenix Duct Clean cleans the full system to TR19 Grease condition and documents it with matching photos and readings - and will inspect and measure a system you are unsure about, so you know whether the last clean did its job.
The service behind the guide
Sibling guides
Sticky floors near the line · Condensation under the canopy · Extraction, duct and filter in one visit
Questions
By the evidence. A proper clean leaves before and after photos from matching positions, micron readings at set points, a works summary, notes on any inaccessible areas and a hygiene certificate. If all you got was a tidier-looking canopy and no paperwork, be sceptical.
Cleaning only the visible canopy and filters and leaving the ductwork behind them. The duct holds most of the fire load and airflow restriction, so a surface-only clean misses what matters most - and usually cannot produce interior photos to prove the runs were reached.
Because the hidden duct runs can only be cleaned through access panels roughly every two metres. If a job was done without opening or fitting them, long stretches of duct cannot have been reached. An honest report notes any areas that were inaccessible.
Deposits verified below 50 microns against the TR19 Grease threshold, with the pre-clean readings recorded against the 200 micron mean and 500 micron point. Actual numbers, not just a photo of clean stainless, are the sign the verification was really done.
Yes. An independent borescope inspection and fresh micron readings show whether the interior was cleaned or only the visible parts. If grease has returned quickly or the symptoms never left, that inspection will usually confirm the original clean fell short.
Phoenix Duct Clean · by the numbers
Book an independent inspection with readings and see exactly where your system stands.