Field Controls 46457600 Operation and maintenance manual

NOTICE: The method of venting the gas pressure switch has been changed
The American National Standard Institute updated their standard (ANSI Z21.10.1) to address
the issue of accidental or unintended ignition of flammable vapors. 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. This sealing
of the access panel into the burner chamber area eliminates the ability to route a bleed tube
from the vent side of the gas pressure switch into the burner chamber.
To eliminate the need of installing the bleed tube, orifices are installed into the gas pressure
switch inlet and vent ports. These orifices are used to restrict the flow of gas through the
pressure switch in the event of a rupture of the switch diaphragm. This method is regularly used
on most gas pressure regulators. 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.
NEW
OLD
Form #46457600 10/03