Shutdown epi2 SNF 2009-02-04 18:15:16: Heater Contactor off+ water flow low

The machine showed the above messge when i tried to bring it to hot idle. I tried it twice and it showed the same message. i found the same problem happened this afternoon also. In the process page, the power of the upper and lower lamps are both 0 at the beginning of the Hot idle mode.