Just noticed an odd thing when doing a brew today. I have a REX-C100 PID controller, and it is the first time I have used my new setup. I noticed that when the PV comes up to sp it stays there exactly. At first I thought, that's great it's keeping the temp perfectly. However once I put my element into manual, (overriding the PID controller), and gave it a bit of heat the PV stayed rock steady on the sp. after a while I thought its taking a long time... At some point I raised the sp by 10 deg out of boredom, and the PV jumped 4 deg C. Very annoying when trying to get mash temps within a deg or so. Has anyone else noticed this, or if you have the same controller, try it out and see what happens.