IQ110 Error Mode
The IQ110 has a bicolor LED to indicate status. If you see solid green, you're golden. But what if it flashes an alternating RED/GREEN? There a supposed to be three reasons for this, but in reality there are four. Presented in order of likelihood:
1) The "LID OFF" algorithm is in effect. The cooker's lid was removed, or the door opened. The IQ detected a rapid drop in temperature, and is assuming that tons of fresh combustion air just reached the fire. So, it is going to hold off from blowing for a while (a few minutes, depending on a few things).
2) For older IQs with the ABS enclosure: The IQ's internal temperature has exceeded 140˚F. This can happen when the enclosure is too close to the cooker, the IQ is in a rainbox in the sun (remember the Greenhouse Effect?), or the IQ is in the desert in the sun. Newer IQs have a temperature resistant polycarbonate case, and this threshold have been increased to 160˚F. Basically, the IQ assumes it is resting on a hot cooker and enters a "self-preservation" mode and stops blowing until the enclosure temp drops below the threshold.
3) The temperature probe is problematic. It could have an intermittent open or short. Competition pitmasters should always have spare probes on hand.
4) Older versions of software could sometimes be exactly 10˚F above the setpoint, bouncing back and forth one ADC bit. The hysteresis designed-in had a bug, which has since been corrected. It did not affect operation in any way, but could be misinterpreted as a fault condition, causing the operator to try to correct the condition, thereby causing an actual problem. If this condition is observed, watch the blower vanes for 30s. If the blower turns on and off within 30s, all is good. The temperature will come back into range shortly and the LED will again become solid green.