I was using my Pinnacle Pro the other day and tipped it a bit too far and the water tool poured water into the unit (what a shit design). Immediately I turned it off, but the unit started flashing every light with a morse code like signal with every color of the light spectrum followed by a single light flashing a few times. I let the unit dry out completely in a bag with a bucket of desiccant. I then plugged the unit in and received the same flashing light pattern. I still tried turning it on while it was plugged in and it worked just fine. Later I tried using it without plugging it in and it wouldn't work at all. Figuring what the hell I took it apart.

(sorry for the lack of pictures) To take it apart you need a very small and thin flat blade screw driver. The display on the front is easily removed by prying at the edges. The button cap will come out with it. You'll be able to see the PCB now and the actual leds. Now if you look at either side of the unit near the heating element end you'll see 3 slits on each side. The middle one looks covered up, but it's actually a locking tab. Press it in with your screwdriver and encourage it to move upward gently. Do this with both sides until you see the heating element start to slide out. Now know that everything inside is connected and the ribbon cable between the heating element and the PCB is VERY VERY FRAGILE. Keep using the screwdriver through the slots at the top and bottom of the sides of the unit to encourage the whole thing to slide out. You might get hung up a bit on the power connector trying to free itself, but with a bit of work it'll come out.

Now you have the whole thing removed. Likely you'll see some corrosion or residue on the pcb components. This is easily cleaned up using a bit of rubbing alcohol (90%). Now look at the battery on the back. The negative and positive terminals will likely show water damage. If you look at the cell itself, it's a CR18650. Many of these are protected with an internal pcb, but I don't know if this one is. My guess is if the water damages the protection circuit in the CR18650 causing the unit to only work when plugged in and act as if a battery isn't installed. To test this I desoldered the battery from the PCB and then plugged it in. I received the same error code (flashing light pattern), but it worked without the battery. I'm not to keen on trying to take apart the battery cell to look at the protection board (especially if there isn't one), but I did heat it up each end of the battery a little bit with my soldering iron. I initially thought I'd just make sure the battery connections were soldered well, then I realized the possibility of there being a protection circuit (not sure if there is one) and figured maybe it had some water in there still or perhaps a connection on there had come loose. So a bit of heat might just soften the solder enough that it would reconnect. I then resoldered the battery back to the main PCB and turned tried to turn the unit on. This time only the bottom blue led flashed as if there was no charge. I plugged it in and it started flashing the bottom blue led as if it was charging. I turned it on with it plugged in and I received no error lights and it worked as normal.

My guess is the battery is toast either because the protection board in the battery (at one end) had failed, or just water damage. I don't think this would solve the issue people have with the flashing red lights, but if you've gotten water in the unit and it's failed with lights flashing like a festival / concert then replacing the battery cell might fix it.

I'm going to order a new battery this weekend and see if replacing it will allow it to hold a charge again.

tl;dr This is not for the red flashing light problem, only for if you got water in the unit and get crazy flashing lights. Battery's built in protection circuit (if there is one) is likely toast or the battery is just damaged from water. Replacing the battery might fix it. New battery on the way to test.