With the continued efforts of the industry, these illegal geysers are being exposed.

These refurbished, reconditioned and recycled geysers have had their day! Image supplied by Plumbing Africa
They are illegal in terms of the fact they do not meet the stringent tests required to qualify for SANS 151.
Refurbished, reconditioned and recycled geysers are meaningless – even if they end up looking brand new. The work done to get the geysers to this point of looking new include methods such as sandblasting, acid washing and so on, which reduce the tank’s material quality. What other ‘tests’ these people do are irrelevant as none come near what is required by the compulsory standard SANS 151’s requirements. When you come across any store flogging these, report it to IOPSA. IOPSA will in turn take it up with the NRCS, who will take action.
So, a cheap geyser is placing customers and their families at risk, and as a plumber responsible for installing such a geyser, you are part of the problem under The Consumer Protection Act and can be held as responsible as the supplier and manufacturer.
If there is no Letter of Authority (LOA) from the NRCS, walk away. It is not worth losing your livelihood for a few bucks saved.