control line not shown and is communicated to controller 350 again increased demand for the operating fluid at outlet 214 will cause the downstream pressure to decrease and decreased demand for the operating fluid at outlet 214 will cause the downstream pressure to increase controller 350 can be set to close slam shut device if the outlet pressure increases above a preset value decreases below a preset value or both if the outlet pressure surpasses a preset value controller 350 will release shaft 340 and allow it to rotate which will move cam 345 out of the way of spring seat 320 with cam 345 out of the way of spring seat 320 spring 325 will move shutter 310 and pad 315 downward until pad 315 seals against second sealing surface 230 of seat insert 220 thereby preventing the flow of the operating fluid through the regulator 10 slam shut device 300 can be reset by placing handle 360 on the end of shaft 340 and rotating shaft 340 until slam shut device 300 is reset as discussed above in the example shown the slam shut device 300 is installed in opening 294 of wall 290 however in some installations having slam shut device 300 installed in this position may cause slam shut device to be inaccessible to a user making reset and maintenance difficult or impossible in these types of installations plate 370 can be removed from wall 292 and slam shut device 300 can be installed in opening 296 of wall 292 opposite wall 290 plate 370 can then be.