I have a Hayward H25FDN Universal Low Nox heater that works but now when I push the Up or Down Temp buttons OR Mode button, nothing happens. I can se the temperature readout fine and there are no error codes. A few years ago I replaced the Bezel & Keypad #FDXLBKP1930 and the Thermistore FDXLTER1930 FD. I should also say that earlier this year if I pushed the buttons many many times, sometime they would blink and I could adjust the temperature but now nothing. I looked at the circuit board attached to the Keypad and can see nothing that looks burnt and the lights are on for POOL and temperature is showing fine. Any suggestions as to what is causing the buttons to not respond?