Before the supplier can name a model, someone has to own three answers
Most selection arguments are really arguments about who is deciding. A cleaning contractor cares about cycle time per job and how far the machine has to be pushed between jobs. A plant maintenance team cares about whether the unit can be fed from the supply already at the bay, and about who services it. A facility manager cares about water, run-off and whether the work can happen while the site is running. Put one named person in charge of the selection, and write down what that person is optimising for, because the same forecourt cleaned by a contractor on an hourly rate is specified differently from the same forecourt cleaned by in-house staff on a fixed shift.
State the decision you actually want, too. "A steam cleaner" is not a decision. "A machine that clears grease from the exterior of sixty vehicles a week, at a position that has a water tap but no drainage" is a decision, and it is the sentence a competent supplier works from. If you cannot write that sentence, no model selection is safe yet.
What is on the surface decides the cleaning mode, and the mode decides the machine
Ask the supplier which mode they are proposing, and why. Dry steam delivers heat with very little free water, so it suits work where soaking a surface is a problem: electrical housings, engine bays, anything close to a cable entry, and vertical or overhead surfaces where water will not stay long enough to do anything. Wet steam and hot-water modes carry more water, lift heavier soil faster, and produce run-off that has to go somewhere. A supplier who does not distinguish these modes is not selecting a machine, they are selling one.
Then describe the soil in the plainest possible terms, because a soil description is what makes a mode arguable. What kind of deposit (loose dust, light oil, cooked-on grease, sugar residue, coolant film, limescale). How long it has been there, since the last clean is the practical measure. Whether it is on a horizontal, vertical or overhead surface. Whether the surface itself is a hazard, for example a walking floor, an area next to food, or a painted or coated finish. Whether the soil is allowed to leave the surface as it is, or has to be contained. Give the supplier the deposit, not an adjective such as "dirty", and ask them to name the mode they expect to use on that deposit.
Two cleaning tasks that look identical from a description can need different machines: a deposit that can be lifted by heat alone is a low-water job, a deposit that has to be flushed off is a water-management job. That single distinction drives more of the selection than any specification row.
The cleaning area: how many objects, how far apart, and how often
Give the supplier counts, not impressions. How many vehicles, machines, hoods, beds or metres of floor are cleaned in one session. How many sessions per week, and whether the work happens inside a production window, after closing, or on a contract visit. How far the operator walks between the first object and the last one, and whether the route crosses a threshold, a doorway, a ramp or a drain channel. Distance and frequency are the two facts that separate a fixed installation from a mobile unit, and a mobile unit from a battery-powered one, so they belong in the enquiry even if you expect the supplier to come and look.
Write the session as a timeline, because a supplier selecting a machine needs to know what happens inside it: how long the operator has, whether the machine can be paused to move, whether the water and power positions are fixed or have to travel with the operator. A session that has to finish in a short window with everything within a few metres asks a different question from a session that runs all day across a site.
If more than one area is involved, list them separately and say which one is the reason for the purchase. Mixed areas are where selection goes wrong: a supplier sizes for the heaviest area, and you pay for capability you use once a month; or they size for the everyday area, and the heaviest job stays manual. Name the area you want specified and the areas you want covered by the same machine, and ask the supplier to state which one their proposal is sized for.
What the site allows, before anyone talks about cleaning
Electrical supply is the first gate. State the voltage available at the position where the machine will stand, not somewhere else in the building, and whether an appropriate outlet and protection device already exist there. Whether the position can be reached with a hose of realistic length is part of the same question. If the site cannot give a supply where the work happens, the selection moves toward battery operation, and that changes the questions you ask about a working session and about charging.
Water is the second gate. Say what water source is at the position and what fitting it terminates in. Tap water is what the published pages for these machines describe as the inlet, but the fitting and the run are site facts and worth stating in the enquiry rather than discovering at delivery. Where there is no water at the position, ask the supplier how the machine is fed in practice and how often that has to happen in your session.
Run-off is the third gate, and it is your answer to give, not the supplier's. Where does the water and loosened soil go after the job: a drain, a gully, a bunded area, nowhere. If the run-off carries oil, grease, food waste or coolant, the route matters for reasons beyond tidiness, and collection or interception becomes part of the job. A supplier who has never asked where the waste water goes has not selected a machine for your site; they have selected a machine.
Access and clearance are the fourth gate. Give the doorway, aisle and lift dimensions on the delivery path, the space where the machine will stand, and the room an operator plus hose needs to move around the object being cleaned. A machine that fits the plan but not the corridor gets parked somewhere inconvenient, and every later answer about supply, water and drainage moves with it. Ask for the machine's footprint as published for the exact unit quoted, and check it against your own tape measure rather than a category description.
How the cleaning equipment in this category is actually arranged
It helps to see the structure of the PowerDe cleaning equipment range before comparing two quotations, because the range is split along the same lines the questions above follow. Fixed units sit at one position, take a mains supply there, and suit a repeating task in a known place; the Fixed Steam Cleaning Machine PowerDe HW02 is the fixed model in the cleaning category, and its own page describes vehicle exterior cleaning at gas stations and parking lots, interior work and engine-compartment cleaning. Mobile and driven units move with the work and suit sites where the objects are spread out, or where the position cannot be prepared once and for all. The mobile driven models in this category are described as dry-steam, wet-steam and hot-water machines for indoor garages and narrow outdoor parking spaces, which is a different working pattern from a unit fixed at one wash position.
Battery variants exist in this category, which is the point at which the supplier's question list should change. Instead of asking about supply at a position, they should be asking how long a working session runs, where charging happens, and whether a shift can be covered without the machine standing idle. Note that the published rows are not identical across the category: one mobile model's page carries a vacuum-suction row, other pages in the same category do not. Do not let a capability from one page be read onto the unit you are buying.
Read the specification rows as that unit's numbers only. Voltage, heating power, tank volume, temperature and pressure figures, and footprint belong to the machine those rows were published for; they do not transfer between a fixed unit and a mobile one, or between a variant with a battery and one without. If a figure you need is missing from the page of the unit being quoted, ask for it in writing for that configuration rather than carrying a number across from a neighbouring model.
Ask about the surface before accepting the cleaning method
Ask the supplier, in writing, which of the published rows apply to the object you described, and which they consider out of scope. Where a surface carries a coating, a seal, a label, a badge, insulation, or an electrical entry, ask what the method does to it and how you would see the damage before it becomes a claim. Write your own protected list: the parts of the object that must not be exposed, and what the operator does instead. A supplier willing to name limits reads as someone who has done this before; a supplier who says the method suits everything should be tested, not believed.
Where the job sits in a controlled environment, food handling, a hospital area, a production hall, separate the cleaning duty from the standard you have to meet. Ask the supplier what their machine contributes, and separately take your own hygiene or process standard to whoever signs that standard off. The machine selection should not be used as the evidence that a standard is met.
Prove it on one of your own objects, with the pass line agreed first
A bounded trial is how a selection stops being a debate. Pick one object, one soiling level that is typical rather than the worst you own, and one operator who will actually do this work. Decide before the trial starts what counts as a pass: the deposit is gone from a named area, the area is dry enough to return to service, no item on your protected list is affected, and the job fits inside the time you have. Agree the pass line in writing with the supplier before the trial, so that the trial settles the question instead of producing a new one.
Run the trial with the machine you would buy, in your position, with your water and your supply. Record what happened while it is in front of you: time per object, how much preparation the object needed, how much run-off was created, what the operator had to do by hand afterwards, and what the operator complained about. That record becomes your acceptance test when the purchased machine arrives, and it is the document that turns a supplier's answer into a commitment you can hold them to. If the trial cannot be run on site, send your object description and photographs and ask for the same fields answered in the proposal.
Independent checks on the machine itself, before handover and on a repeat or fleet order, are worth naming in the enquiry as a deliverable: what is checked, against which published rows, and what document records the result.
The cost a model selection commits you to
Ask every supplier for the same line items, so the quotations sit side by side. Purchase price and what is included in it (the wand, nozzles, hoses, brushes, and the lengths they are supplied in, all stated rather than assumed). Site preparation before delivery: supply work, water connection, drainage or collection, and who pays for each. Consumables and wear items with the interval each is replaced at, its price, and how long it takes to reach your site. Service: the interval the warranty depends on, who is allowed to perform it, and the cost of that visit. Training, and whether the next intake of operators can be trained the same way. If a supplier answers "standard" for any line, that cost appears later, in your budget rather than theirs.
Then compare the quotations against your session facts, not against each other. A cheaper machine that needs a second pass on your deposit, or that cannot reach your furthest object without being re-fed, is not cheaper. A capable machine that sits idle between two monthly jobs is not capable. Write the two numbers that matter for your case, time per session and cost per session, and let the trial record fill them in rather than the brochure.
If your duty is not an obvious catalogue fit, say so early
Some duties sit between catalogue entries: a site with no drainage at the position, a session that has to move between floors, an object too large or too delicate for the standard accessories, a task repeated across many locations that has to be performed identically. In those cases the useful question is not "which model do you recommend" but whether the duty can be configured, and what changes in the proposal if it is. Describe the duty the way you described the deposit, and put it through customized steam cleaning equipment rather than forcing a catalogue model to carry it. Ask what a configuration changes about price, delivery, spares and warranty, because a non-standard unit can cost more to keep running than the difference it saves on the order.
What a good supplier should ask you before recommending a model
Judge the supplier by their questions. A selection worth accepting arrives after someone has asked: what the deposit is and how old it is; which cleaning modes they propose for it and why; how many objects, how often, and how far apart; what supply, water and drainage exist at the position and where the run-off goes; the delivery path, the standing position and the clearance an operator needs; what on your object must be protected; whether a trial is possible and on what; the consumables, service interval and training that follow the purchase. Send the same written list to every bidder and score each answer as stated, qualified, or missing. An unanswered heading is not a saving; it is a cost with a later date.
Close the selection with a short written record: the model proposed and the page its figures came from, the mode chosen and the deposit it is for, the session facts it was sized against, the site answers (supply, water, run-off, access), the trial result and the pass line, the cost lines with their intervals, and the protected list. A model selection that cannot be written down on one page is not decided yet, and the supplier who cannot give you that page has not finished the job.
