Setting your personal hostility aside, I am always happy to acknowledge a valid technical point, and I appreciate you bringing the latest revision of the Thetford Triplex manual to my attention. Spinflo and Thetford cookers were historically the default choice across the boating industry for decades. However, as your link highlights, Thetford’s current installation manual limits its stated scope to caravans, campers, and holiday homes under EN 1949, omitting explicit instructions for small craft under BS EN ISO 10239. This actually proves the exact point I have been making throughout this thread: a Gas Safe engineer cannot rely on historical practice or installer assumption. We are legally bound to the written scope of the current Manufacturer's Instructions. This is precisely why it is always prudent to review the MIs prior to or during an installation—manufacturers update these documents over time, and suppliers rarely notify installers when a product scope or specification has changed. Consequently, this older guide is now out of date, and I will be amending it and removing any non-compliant units from my recommended appliance list.
