I solved my various ignition problems on my Minimax 400. Wouldn't ignite, shut down etc. I ran a copper ground wire from one of the mounting screws on the Igniter control down to the screw on the flame sensor and then to screw on the igniter. I have not had any ignition problems or error codes since. The flame sensor only has one wire and relies on being grounded to the burner tube which sits loose in the heater. Grounding problems went away with the addition of the ground wire. Hopefully this will help someone. It can't hurt to add the ground wire.

I have not used my heater for about a year. I installed new propane. I only get a power led. When I switch the rocker switch to pool or spa nothing is happening. Had a tech come check it out and he said it needed a new circuit board. He wanted way too much for the board so I bought an OEM on line and installed it. Nothing changed. I can see that the water pressure switch is working. It is 10 years old. Got any ideas?

The fan error code you gave might be better asked on the link below... Here is a link that might be useful: Pentair

The original symptom was that there was no information on the DDTC except for a Pressure SW indicator. Replacement of the DDTC module fixed that. What I have found since I posted is that I have only 13.7vac coming off the transformer, with good line voltage going in. It seems that these transformers are fairly standard, so I will be getting one tomorrow. That might explain why my DDTC fried, right? Seems it would be simple to have incorporated a low volt fault system to keep a 5.00 transformer from killing a 300.00 DDTC.