Hi - We are on our second Hayward heater. It is getting electricity as the standby light is lit. However, when I try to switch it to the pool, nothing happens. The light only stays on standby. The heater shows no error code. I unscrewed the four screws around the display panel but all connections looked okay. The other day the pool was low on water (the autofill is turned off) and the skimmer wasn't receiving a full amount of water causing the error code LO to display along with the service light coming on. That was resolved by putting more water in the pool. I actually had turned off the autofill a couple of years ago after it broke. We have never had problems with this heater for the three or so years we have had it.
thank you for your help and advice!