I have done lots of tests with different transformers over the years. I\'ve tried toroidal and conventional and found 15v was the most optimum. Anything over 16v causes the heat sink on the regulator to get quiet warm and below 14.2 is not enough to regulate the output voltage to 13.8vdc.
Interestingly, if you cant find an original Comfort transformer, try A Fermax 4800 1.5 amp rated at 12vac, but actually give out 15.5Vac
Interestingly, if you cant find an original Comfort transformer, try A Fermax 4800 1.5 amp rated at 12vac, but actually give out 15.5Vac