Based on the information you provided, it sounds like you have already done a thorough job troubleshooting and attempting to resolve the issue with your DCS Fisher Paykel gas oven.
If the oven is not reaching high temperatures even after you have replaced the igniter and dual gas valve, and swapped the circuit board from the working side, there are a few other things you can check:
- Check the oven thermostat: The thermostat is responsible for regulating the temperature in the oven. If it is not functioning properly, it may be preventing the oven from reaching high temperatures. You can test the thermostat with a multimeter to see if it is functioning correctly.
- Check the oven temperature sensor: The temperature sensor is located inside the oven and sends temperature readings to the control board. If it is not working properly, it can cause the oven to not heat up to the desired temperature. You can test the sensor with a multimeter to see if it is functioning correctly.
- Check for obstructions in the gas line: If there is a blockage or obstruction in the gas line, it can prevent the oven from getting enough gas to heat up to high temperatures. Check the gas line for any debris or blockages and clean them out if necessary.
- Check the regulator: The regulator is responsible for regulating the pressure of the gas going into the oven. If it is not functioning properly, it can prevent the oven from heating up to high temperatures. You can test the regulator with a gas pressure gauge to see if it is functioning correctly.
If none of these solutions solve the problem, it may be best to contact a qualified technician to further diagnose and repair the issue with your oven. They will have access to a service manual and specialized tools needed to diagnose and repair the oven.