Jonty wrote:
Hi Jeff PLCs (Ex models) are safe in Victoria as we utilise them in Class 1 Hazardous zones in my workplace (intrinsically safe) - maybe it comes down the level of certification given the PLC module? The big concern from reading the document is the make up of LPG between Australian and New Zealand, different gas mixtures - the dangers are not worth it (explosive & carbon monoxide poisoning). Will be interesting to see if Stonka have tried to achieve compliance with the Australian regulations - if so it may open up a whole lower end marketing opportunity considering the exchange rate (off set the costs of production\certification)? Jonty
Yes John PLC's are allowed to be used in Victoria for control of equipment, however, Energy Safe Victoria will not allow the gas safety controls to be managed by a PLC, regardless of the brand (I have Allen Bradley, Siemens, Moeller, Eaton, etc. - all Globally recognized and locally certified equipment). Additional mechanical controls (extra relays and proving switches) are required. It's ridiculous as the additional components are basic and low value but they need to be designed and installed, tested and documented by the authorized and licensed contractors as part of a submission for commissioning compliance. I would put my trust in a PLC before a relay, but it's still just the way it is right now as I'm in the middle of certification - the regulations simply have not moved with the times (I worked on complex PLC's in 1984 - 1993 and back then they were very safe and reliable - as they are still today). It's likely the Stonka already contains superior or vastly improved gas controls compared to the majority of installed gas hot water systems and space heaters embedded in many homes over the last 30 years. Some of those are frightfully dangerous in their design and safety - particularly the treatment of the toxic emissions from the actual burning of the fuel in confined spaces.
