My pentair minimax NT LN 250 is giving me a E04 code. I have changed the thermistor, the ignighter, cleaned out the burners as well as the Gas manifold. The fan comes on, the temp is displayed but it will not light up. I hear ithe clicks but can't smell any gas.

I bled the line at the union but success. The unit will stay on for about 10-15 min. And then it gives the E04 code again. Fan stays on as well, just no flame.