I had a problem this week when the electrical company came out because all the heaters were not working. It was promptly fixed but then all the heaters started coming on a 10 p.m. and were hot by 1 a.m. We were used to them coming on about 12.00 and finishing about 7 a.m. As we did not want this extra heat at night, we tried not putting the heaters on until midnight but they did not trigger and so we had no heat the next day at all.We called the electricity company and they came out and the man admitted we had been given a 57 teleswitch whereas we should have had our normal 7teleswitch. The difference is we get a continous economy 7 through the night with a teleswithc no 7 whereas the 57 starts about 10 p.m. and goes on and off at various time during the night. I prefer the 7 because my washing machine and immersion heaters are on timers to take advantage of the low rate.