[. . . ] This standard update forced the water heater manufacturers to make changes to there water heaters. [. . . ] Changes with the design of water heaters have necessitated a change in the installation requirement of a bleed tube on the gas pressure switch used in our water heater control kits. The change in the ANSI standard has forced the redesign of the air intake to the burners on the water heaters, resulting in the sealing of the access panel of the burner chamber. These orifices are used to restrict the flow of gas through the pressure switch in the event of a rupture of the switch diaphragm. With the removal of the bleed tube, a screened cover has been added to the vent port of the gas pressure switch to eliminate foreign material from getting into the vent port. OLD NEW Form #FRESHMIST FM 90 10/03 [. . . ] These orifices are used to restrict the flow of gas through the pressure switch in the event of a rupture of the switch diaphragm. [. . . ]