Fireplace was not maintaining set temp on thermostat. Customer had been noticing burners dropping out at times during a call for heat. Performed full cleaning of fireplace, cleaned glass. Found small stress fractures in corners of glass. Not quite a crack but definitely something to keep an eye on. After performing maintenance on fireplace it is working well , running consistently and burners are not dropping out. Advised customers to keep an eye on the operation of the fireplace and call us if the problem reoccurs. Office will put together a quote for red tag