I've recently acquired a Radius 46 and stripped it down last night. When I dis-assembled the filler cap, I found that the brass cup was on the wrong end of the spring: As found: Correct assembly: As far as I can see, the only function of the cup is to concentrate the pressure from the spring onto the centre of the brass disc. Would the SRV element of the filler still have functioned if assembled as in photo 1? I may give it a try once I've fettled the stove (but outside and standing up-wind). Terry
Thank you George. Another 5 minutes spent learning something I didn't know that "I didn't know". And a fine job by Presscall in the post linked to. Ken in NC
Terry, I believe you're on the right lines regarding the purpose of that brass cup, to distribute the pressure of the spring over the thin brass disc diaphragm, which would degrade if the spring (which is quite powerful) were in direct contact with it. John