A heating element on a data sheet says 6 kW. That number tells a buyer nothing about whether the machine will still be making steam late on a Friday, after the tank has been emptied twice and the mains water has gone cold. An acceptance check for heating power is the part of a steam equipment purchase that is most often skipped and most often argued about afterwards, because heat is the specification that quietly decides cycle time, chemical use and labour hours. The check below turns published figures into measurements, and turns missing figures into written questions the supplier must answer before the machine is switched on.
What the acceptance check has to prove
Heating power in a steam cleaner is a promise with four parts, and an acceptance check that tests only one of them is not a check. The first part is whether the heater draws the current its published rating implies, on the supply the site actually has. The second is whether the machine reaches a usable state from a genuine cold start, not from a warm tank that was left running overnight. The third is whether it holds temperature and pressure at the nozzle while an operator works, which is where a machine that looked fine on a bench starts to disappoint. The fourth is what the machine does when it runs out of water, when the supply trips, or when it gets too hot - the protection behaviour described on the product page, which must be witnessed, not assumed.
Write these four as line items on the acceptance sheet before the machine arrives. A punch list produced after a failed trial is a negotiation; the same list agreed in the purchase order is a condition of payment.
Fix the reference conditions before anyone touches the switch
Two identical machines can produce two different results if the conditions are not recorded. Before the trial, write down the water temperature in the mains, the ambient temperature in the working area, the supply voltage at the socket under load, the tank fill level, and the mode selector position. For the Fixed Steam Cleaning Machine PowerDe HW02, the published figures that anchor this record are a 6 kW heating element, a steam temperature of 160 C, a vapour pressure of 0.8 MPa, an 80 L SUS304 tank, a 220 V working voltage, and a tap-water inlet with a 4-point internal-tooth joint in 1/2 inch. Those are the numbers to measure against.
Anything the supplier has not published - the cold-start time, the recovery time after the tank is emptied, the tolerance band around the steam temperature - should be requested in writing before the trial and entered on the same sheet as blank fields for the supplier to fill in, not left for the installer to improvise on site. Mode definition belongs in the same record. A high-pressure steam cleaning machine that switches between dry steam and wet steam will read differently in each mode: wet steam carries more water and therefore absorbs more heat, dry steam leaves the nozzle hotter and dries the surface faster. State which mode each measurement was taken in. A comparison made across modes is not a comparison.
The instrument and paperwork that must be present
An acceptance check needs four instruments and one form. Everything else is opinion.
- A clamp meter capable of measuring the heater current at the machine, with the reading taken while the heater is actively running and not during a standby period.
- A contact or infrared thermometer for the nozzle and the steam path, plus a reference reading of the incoming water temperature.
- A pressure gauge reading taken from the machine's own gauge, noted with the time and the mode.
- Two timers: one for cold-start to first usable steam, one for recovery after each rest period or refill.
- A log sheet with the model and serial number, the operator, the observer, the time of every reading, and a signature line for each party.
Ask the supplier, in the purchase order, to bring the calibration evidence for any gauge they intend to rely on. A machine accepted on an uncalibrated gauge is a machine accepted on the installer's word.
Check one: the heater circuit under load
Measure the current at the machine while the heater is on. A published 6 kW at 220 V gives a straightforward expectation for the current, and the measured value should sit in the same region. Record the actual voltage at the same moment, because a supply sitting low will make a healthy heater look weak.
Then walk the supply side of the installation: the protective device rating, the cable size and length between the distribution board and the machine, the socket or isolator rating, and the earthing arrangement. A heating element that trips the board on the second rest of the day is not a machine fault; it is an installation the acceptance check should have caught while the punch list still had value.
For battery-fed equipment the equivalent check is different. The hand-pushed hand-pushed steam cleaning machine in the PowerDe range is published with a 4.5 kW PTC semiconductor heater, a 50 L clean-water tank, and a 48 V working supply, with dimensions of L1150 x W520 x H1030 mm. On battery equipment, acceptance must also record the charger output, the runtime measured under a realistic work pattern, and what the machine does as the battery falls. Battery capacity and runtime are not published on that product page, so the buyer should request those figures in writing and treat a runtime measured during acceptance as the number the site will plan around.
Check two: cold start, not warm start
Most demonstration units arrive warm. Insist on a genuine cold start: the machine filled from the site mains, switched off, left long enough for the tank and the water inside it to reach the temperature of the room, then started in front of the observer. Record the time from switch-on to the moment the first steam that is actually usable at the work surface reaches the surface, and define "usable" before the trial - for example, steam that is visibly continuous at the nozzle and consistent enough to lift grease from a test panel without a second pass.
Run the cold start twice. A first run that warms the housing changes the second run's answer, and the difference between the two numbers tells the buyer what the machine will do on a shift where it is started cold every morning rather than left idle in a warm garage.
Check three: what arrives at the nozzle, not what leaves the boiler
The published 160 C and 0.8 MPa belong to the machine, and the work happens at the nozzle. Measure with a test panel rather than against empty air: a greased steel plate, a section of floor grout, or a small panel of the surface the site actually cleans. Run one pass in dry steam and one in wet steam, and judge both against the same panel so the difference is visible.
Three observations settle this part of the check. The spray pattern should be even and should not spit water between bursts. The machine should switch between dry and wet steam without a long dead period and without a pressure drop that the gauge makes obvious. The steam should still be lifting the test soil after several minutes of continuous work, which is the point where an undersized heater or an undersized tank starts to show.
Check four: recovery, emptying and refilling under load
Heat is consumed, and the question a facility cares about is how quickly it comes back. Time the machine after each of these events: a rest period of ordinary working length, a full tank empty, and a refill. Note the mode, the time, and what the operator had to do in the meantime.
Then test the water-shortage response deliberately and under supervision. The product literature for these machines lists leakage, short-circuit, high-temperature, high-voltage and water-shortage protection; the acceptance sheet should carry each of those names and a column for what was observed, rather than a tick for "protections OK". If the machine can be refilled while running, confirm that it may be, and confirm what the operator should do if it cannot - a machine that must cool before refilling has a working rhythm that changes the labour plan for a large area.
Check five: duty continuity and the protection response
A short trial cannot show fatigue, and fatigue is where heating power becomes a procurement problem. Plan a continuous run that matches one realistic working block for the site, not a five-minute demonstration, and record the nozzle condition at the start, middle and end of that block. If the supplier has published a duty cycle or a recommended working period, test against it. If they have not, ask for it in writing and make the answer part of the document pack, because the alternative is that the site guesses, and a site's guess is usually optimistic.
Witness the safety response, don't read about it. Trigger a high-temperature condition and record how the machine stops and how it is restarted. Trigger a low-water condition and record the same. Confirm that the machine stops behaving as intended rather than merely showing a lamp, and record the reset procedure in the operator instructions that come with the handover.
Check six: the site conditions the machine cannot compensate for
Heating power is also a site question. The published footprint for the fixed machine, handles included, is 1,200 x 800 x 1,200 mm; the buyer should confirm that the route from delivery to the working position is wider than that, that doors and lifts accommodate it, and that the working position has a water supply with the matching 4-point internal-tooth 1/2 inch connection. Confirm that the supply at that position can carry the heater under load, and that there is somewhere to drain the tank without flooding a walkway or sending hot water into a trap that was not designed for it.
These items are usually where a heating-power dispute starts. A machine that is correctly built for a 220 V supply will still underperform behind a long extension lead, and an installer's report that blames the operator is far easier to accept after the site has already signed for delivery.
The document pack that closes acceptance
Acceptance should end with a small bundle rather than a handshake. It should contain the log sheet with all measured readings and signatures, the supplier's written answers for every figure that is not published, the calibration evidence for any instrument relied upon, the operator instructions including the reset procedure for each protection, the spare-parts list with the heater element identified, the warranty terms with what voids them, and the punch list with a date against every open item.
Two practical terms protect the buyer in that moment. Keep a defined retention against the purchase order until the acceptance sheet is complete, and state in the order that payment follows a signed acceptance sheet rather than delivery. If the trial produces a figure that misses the published expectation, the record made during the trial - time, mode, voltage, water temperature, tank level - is what allows the buyer to ask for a fix instead of an apology.
The figures quoted above are those published on the manufacturer's product pages: HW02 with 220 V supply, 6 kW heating power, 160 C steam temperature, 0.8 MPa vapour pressure, 80 L SUS304 tank and 1,200 x 800 x 1,200 mm including handles; the hand-pushed HMW3 with a 4.5 kW PTC semiconductor heater, 50 L clean-water tank, 48 V working supply and L1150 x W520 x H1030 mm dimensions. Cold-start time, recovery time, duty cycle, tolerance bands, battery capacity and runtime are not published and must be obtained from the supplier in writing. The published product page for HW02 describes vehicle exterior cleaning, interior vacuuming and disinfection, and engine-compartment cleaning; use this acceptance method for any machine being handed over, and confirm the intended cleaning scenario with the supplier before it is written into a site procedure.
