Moen sent me 2 cartridges # 1224 as they said it is what fits from the info I gave them. Got handle and trim part off easy enough top nut holding it in. For the life of me can't get it to come out so ready for ideas. It can't thread in as it is keyed with a tab to locate and replacement has no threads just 2 o-rings. I am a bit worried about heat as there is plastic trim still there but could try a wet cloth on top of that and don't want to melt the plastic cartridge either. I was tempted to turn the water on but suspect if it worked I would have a missile and a flood. I am up for any and all ideas.