Has anyone had any success reprogramming a Sontex 531 heat meter calculator using the Prog531 software? The calculator on my Sontex 449 heat meter has died but I have a spare Sontex 531 calculator which should be compatible with the existing Sontex 449 flow meter (the 531 is already set up for Qp 2.5 in return with PT500 sensors like my existing system), but the 531 would need to be reprogrammed with the correct pulse rate for the flow meter. I have borrowed an optical head and cut-down version of the Prog531 software - and I can connect OK to the 531 but the software doesn’t seem to allow me to change the pulse rate, just view It. I’m guessing either I need a “premium” version of the software to be able to change these key parameters or it might be the flow pulse rate is locked out permanently. Sontex distributors will no longer service these old models.
Tagging @glyn.hudson for eyeballs.
Jez has my optical head and the prog531 software that I had access to; but I think I have the noddy version of prog531.