Hayward Error Code

I have a Hayward H Series heater for my in ground pool (natural gas and self ignition). I had power to the unit but it wasn't turning on. I replaced the fuses and now the unit is turning on but it is staying in "standby" mode with a "bo" error code. I tried holding the mode and down buttons for 3 seconds but to no avail. I did shut off the gas before when I was trying to figure out what was wrong with the unit. I thought I may have to light the pilots but when I opened the unit, it stated on the inside panel not to try to manually light the pilots. If anyone has any insight I would be very grateful!



TFP Guide
Jun 4, 2012
western NY
The FC4 is your transformer secondary protection. In other words it is the fuse that is on the output side of the transformer (low voltage side). If it keeps blowing there is most likely a short somewhere in the wiring. If you are handy with an OHM meter this should be fairly easy to track down.