Two hoods in the same kitchen can behave very differently under the same cleaning crew and the same machine. One comes back clean in a short visit; the other needs a second pass, a different approach, or a method that has nothing to do with steam. The difference is rarely the machine itself. It is the set of site conditions around the hood: how it is built, how access works, what is stacked on and behind it, what the building permits, and how the kitchen is scheduled around it. A buyer who walks those conditions before committing will spend far less on a trial that was never going to succeed.
For a restaurant or central kitchen, commercial range hood grease removal and the exhaust path above it are the surfaces that most often get postponed, because the work looks disruptive and the outcome looks uncertain. The condition list below is the one to work through with the equipment supplier in writing, so that the answer for your hood is measured rather than assumed.
Hood construction and access openings
Start with what the hood is made of and how far the crew can reach inside it. Filter type and frame design decide what can be removed and washed separately, and what has to be treated in place. Some hoods lift out a full filter bank; others use fixed baffles or a plenum that only shows a narrow opening. Stainless gauge, weld seams, gaskets, and the condition of any coating on the interior all change what a crew should attempt, so ask the kitchen or the installer what the interior surface actually is rather than judging it from below.
Access geometry is usually the deciding site condition. A hood with a clean access panel and a flat working face around it is a different job from one where the crew can only reach through a small opening, or where the fan section sits behind ductwork that no one has opened in years. Record, per hood: opening size and location, whether the fan housing can be opened at all, the distance from the nearest floor or platform to the working face, and whether the crew can stand somewhere that is not directly over the cooking line.
Power, water, and drainage at the hood
A fixed machine that runs on a single-phase supply is only usable if the kitchen has a supply that suits it, in a position the crew can actually reach, with cable runs that cross no cooking line and no guest area. Ask the supplier to state the working voltage and heating power for the exact unit quoted, and check those numbers against the kitchen's distribution before the visit. Any voltage and heating-power figure you are given belongs to the unit it was measured on, not to the machine that arrives at your building.
Then confirm the water story. Where the machine connects to the supply, and with what fitting; how far the hose has to travel; whether a tap of the right size and thread is anywhere near the hood; and where the run-off goes. Greasy run-off coming off a hood cannot simply fall on the floor and wash into a floor drain that also serves a food preparation area. Ask the building what the permitted route is, and whether it needs a screen, a collection tray, or a temporary capture. In many kitchens this single drainage condition, not cleaning power, is what decides whether the work can be done on a normal operating day at all.
Deposit type and how long it has been there
Fresh grease film and a cured, dark, hardened layer are two different problems, and site conditions decide which one your hood has. A hood cleaned on a short cycle keeps deposits soft and reachable. A hood with a long gap between cleans, or one downstream of a grill or char oven, tends to build a thick layer that has been baked by radiant heat. Where the build-up has been heated repeatedly, treat dwell time and access to the surface as the real constraints, not raw force, and be cautious about anything that pushes on a coating or a seal.
Ask for a small test patch on a hidden or sacrificial area and photograph it before and after. That one step converts an argument about capability into a comparison you can judge, and it is where the difference between a degreasing routine carried out on a short cycle and an emergency clean attempted after a long gap becomes obvious.
Electrical and control components near the work
Lights inside the hood, fan motors, variable-speed drives, thermostats, and the wiring that feeds them sit exactly where a cleaning crew has to work. Whether those items are shielded, sealed, or merely open to the kitchen air changes what the crew should do with any wet process, and it should be written into the exclusion list before the shift. The same applies to bearings, belts, and any opening that should not be wetted. Isolation of the fan and lighting circuits, with the isolation logged rather than remembered, is part of the site condition and not an optional extra.
Kitchen operating schedule and service windows
The kitchen itself is a site condition. Which hours are free, whether extraction has to run during service, whether the hood has to be back in service the same night, and how many pieces of equipment go out of action at once all constrain the method. A condition that makes work impossible during the day is often harmless overnight. Write down the window, then design around it: filter bank out of service for how long, one bay or the whole line, and what has to be reassembled and checked before the first cooking shift.
Airflow through the room is another schedule item. Steam and hot water inside a kitchen with extraction running hard behave differently from the same work in a still room, and the crew needs to know what the extraction will be doing during their shift.
Clearance, floor, and safety conditions around the hood
Measuring the path matters as much as measuring the hood. A mobile unit has to travel from its parking point to the hood through aisles, past service doors and under low services, and a wet floor next to a hot line is a hazard the site has to control. Note floor material and falls, whether the area can be cordoned, whether a platform or ladder is permitted, and whether other trades or a gas line share the space.
Machine-side safety features belong on the same site sheet, because the building will ask about them. The product records on this site name leakage, short-circuit, high-temperature, high-voltage and water-shortage items; list the items you were actually given in writing for the unit arriving on site, and do not assume a count or a feature transfers between models or between a with-battery and without-battery variant.
Site records, permits, and who signs off
Before any work starts, settle what the site requires on paper: the last cleaning record for this hood and duct, the fan and electrical isolation procedure, hot-work or permit rules that apply to the area, and the name of the person who signs the hood back into service. Where a building maintains its own extraction hygiene records, the cleaning method you choose has to fit inside them. This is also the moment to decide what the crew will hand back: which surfaces were treated, which were excluded and why, and what still needs attention.
Machine fit against those conditions
Only after the condition sheet exists does a machine choice become a rational one. A fixed installation suits a kitchen with a permanent, compliant supply and water connection near the work, and where the same method repeats. A fixed steam cleaning machine suits that case, while a mobile steam cleaning machine suits a site with no suitable fixed supply, several hoods across separate buildings, or a schedule that moves around service. Two questions settle the fit: does the machine get its power and water at your hood without a temporary installation, and can it physically get there. If either answer is no, no amount of cleaning power fixes the plan.
Whatever the answer, insist on figures for the exact unit quoted rather than figures from a brochure: steam temperature and pressure as published by that page, tank volume, and the mode selection between dry and wet steam. Read tank volume as capacity, not as working time, and read any temperature figure as a generator or boiler value, not as the temperature arriving at the surface. Where your hood's conditions need something the catalogue does not describe, that is a customisation conversation, not a workaround.
A short condition sheet to take on the walk-through
Take one page per hood and fill it in with the kitchen and the supplier together: hood construction and interior surface, filter type and removal route, access openings and reach, distance and route from the parking point, power supply available and cable path, water connection point and fitting type, permitted run-off route, electrical and rotating items to exclude with their fallback method, deposit age and character from the last record, the free service window, cordoning and platform rules, and the name of the person who signs off.
Then run one bounded trial on one hood with an acceptance standard agreed before the first pass and a stop condition written down. If the trial holds against those site conditions, extend the same method to the rest of the kitchen. If it does not, you have spent one shift finding out which condition was the blocker, and that answer is worth more than any specification you could have read first.
