My main question was Does the IQ900-RS board replace the 'Front Board'? (is front board the board that the tri sensor plugs into?)
I just replaced this sensor mid July of 2014. I am now getting 172 and 186 errors, and immediately figured it was the board, since I just replaced the sensor. Now after reading multiple posts it looks like it very well could be the sensor since they go out all the time. I did the checks on the board and they are all fine except for salinity check, it was 2.5 instead of 2.8gpl, but I did have to recalibrate the salinity, which is the reason for the difference (it states that in the trouble shooting guide, I can recalibrate and get it to 2.8 but the salinity is off when I do that) I sent an email to check on the warranty for it but I bet it isn't over a year, still waiting to hear back)
My original thought was if it is the board, I would upgrade to the IQ900-RS to ditch the PDA, the PDA buttons don't always work right.
My question was, the board you get with the IQ900-RS, does that replace what I believe is the 'Front Board'? It is the board where the tri-sensor plugs into, and had the chip with the firmware version on it (08020A07). My thought was, at least I would have an upgrade and ability to control the pool from my phone or the internet, and thought it replaced the board the tri sensor plugs into, so that may actually fix the problem.
If I am really looking at another sensor, I will probably put the money into that instead of upgrading the board.