Had my annual service done mid December and all was fine for about 3 weeks then problems. The unit will start, go through the purge cycle then it ignites but within seconds shuts down. Have replaced numerous Aqua-Hot recommended parts and the problem persists. The last suggestion from A-H was to separate the exhaust pipe to see if there’s some blockage there. Tried but the joints are tight and am unable to separate them. Am considering cutting but before I do thought I might see if anyone else has...