Hello, i have a Takagi T-K3 i am getting a code error 991. It had been operating flawlessly for about 4 months now when i turn it on nothing happens at all i have checked and cleaned my sensors. checked air intake and exhaust i did make some minor changes to the exhaust (added a condensate trap). I still try to start it but nothing happens i still get the 991 error code. Is there a way to reset this code or does it go away once the problem is fixed. Thank you Mike.