Warranty and serial-number checks are the buyer’s defence against old stock, refurbished units, demo machines, and unclear service responsibility.
This matters because oxygen concentrators are long-life medical devices. A machine that looks new externally may have an older manufacturing date, unclear hours, expired channel warranty, or weak spare-parts support.
What to collect before payment
Ask the seller for:
| Document or proof | What it proves |
|---|---|
| Serial-number photo | Identifies the exact machine |
| Box label photo | Helps match box and unit |
| GST invoice draft | Links serial number to buyer and warranty |
| Manufacturing/import date | Shows stock age |
| Warranty start date | Clarifies whether warranty begins at sale |
| Dealer authorisation proof | Reduces unauthorised-channel risk |
| Service-centre confirmation | Shows who will handle repairs |
| Hour-meter photo if available | Helps detect used/demo stock |
If the seller refuses serial-number documentation before payment, treat that as a risk signal.
How to check the serial number
Use this sequence:
- Ask for the serial-number label on the machine.
- Ask for the box label.
- Ask for the invoice to include the same serial number.
- Ask the seller to confirm manufacturing or import date.
- Ask when warranty starts and who honours it.
- Ask the nearest service centre to confirm support for that serial.
- At delivery, record unboxing and first startup.
For machines with an hour counter, photograph the hours at delivery.
New, old stock, demo, or refurbished?
These categories are not the same:
| Status | Meaning | Buyer stance |
|---|---|---|
| Fresh new stock | Recent stock with full warranty | Best case |
| Old stock | Unused or lightly handled but aged | Accept only with discount and warranty clarity |
| Demo/open-box | Used for display or demonstrations | Requires hour reading and explicit disclosure |
| Refurbished | Previously used and repaired or restored | Buy only with strong testing and written return terms |
| Unclear | Seller will not specify | Avoid |
The word “new” is not enough. Ask what kind of new.
Imported-brand warning
Imported 5 LPM concentrators may still be good machines, but Indian channel risk is real.
Philips EverFlo has been officially discontinued globally. That does not make every EverFlo bad, but it does mean buyers should verify:
- serial-number age
- whether the unit is old COVID-era stock
- whether the box was opened
- invoice date
- warranty validity
- authorised-service continuity
- compressor and sieve-bed availability
Apply the same verification logic to AirSep, Nidek, DeVilbiss, and other imported units where fresh supply and spares are not obvious.
How this affects the 5 LPM shortlist
HHZ would shortlist by both machine quality and proof quality:
- Oxymed Mini 5 LPM is strong where the local dealer can prove fresh stock, warranty, and support.
- Home Medix HM-KV is strong where authorised service is confirmed; its 3-year / 10,000-hour warranty and hour counter are useful verification signals.
- Philips EverFlo should be treated as a verification-heavy purchase, not a default.
- Nidek Nuvo Lite, AirSep VisionAire 5, and DeVilbiss 525 need fresh-stock and spare-parts proof.
Delivery checklist
At delivery:
- Match serial number on unit, box, and invoice.
- Photograph the serial label.
- Photograph box condition.
- Record unboxing if possible.
- Run the machine and check alarms.
- Ask for purity testing if the dealer can provide it.
- Save warranty registration proof.
- Save dealer and service-centre contacts.
Do not let urgent delivery replace documentation. A delivered machine without traceable warranty is a weak long-term oxygen purchase.
Bottom line
Warranty and serial-number verification should happen before payment, not after a fault appears. For Indian oxygen concentrator buyers, the paperwork is part of the product.
For more condition checks, see how to check if an oxygen concentrator is new or refurbished, old stock oxygen concentrators in India, and Philips EverFlo discontinued: India alternatives.