i have a baxi solo 3 pfl 30. it starts up ok from cold but after a short time and before the heating or water has reached an adequate temp, say 10 minutes, the flame goes out-the fan still runs, and it keeps clicking, trying to re-ignite.it does re-ignite after a while but again, only for a few minutes. i have just replaced the pressure valve but it's still the same. i have been told that if i leave it "clicking" it may burn my PCB out. any ideas what this could be or the part which is faulty? any help would be greatly appreciated before i call a engineer out.