I have a 12 year old Hayward 2100 pool/spa control that won't give me proper temperature sensors.
It started with the water temperature reading really high. We're having an ice storm and it said the water was 98 degrees. The air temp was reading correctly and as the temperature dropped it went into ICE mode. I power cycled the control and now it just says pool temperature is OH and won't display air temperature even during the day when it got above 35 F. Since the power cycle I have to turn the pump overnight since it won't start ICE mode. The OH code is >112 degrees. There are also SN1 and SN2 codes for individual sensor failures. Those aren't being displayed.
With the power off I looked at the board and I don't see any blown fuses or burnt components, it doesn't look like there are any fuses for the temp sensors anyway. Unplugged/replugged them anyways to make sure there is good connection. The wires look fine and the air temp sensor looks undamaged.
The 2100 line appears to be discontinued and replacement parts are scarce. I'm hoping I can still fix it without having to change out the control system entirely. Has anyone had something break in this manner before? I think it's unlikely that both sensors broke the same weekend and more unlikely that they also both broke in such a way that I don't get the sensor error codes SN1/SN2. Is there something else I can check on the board?