CSA /ANSI Z21.23:22 CSA 6.6:22

Preface 

This is the first edition of CSA/ANSI Z21.23/CSA 6.6, Gas appliance thermostats . It supersedes both ANSI Z21.23-2010, Gas appliance thermostats, and CAN1-6.6-M78, Gas appliance thermostats. This Standard has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group. This Standard has been approved by the American National Standards Institute (ANSI) as an American National Standard. This Standard is considered suitable for use for conformity assessment within the stated scope of the Standard. 

Scope 

1.1 This Standard applies to newly produced gas appliance thermostats of the integral gas valve type having a maximum operating gas pressure of 1/2 psi (3.5 kPa) or electric type (see Clause 3), constructed entirely of new, unused parts and materials. This Standard does not apply to an electric type comfort heating thermostat (wallmounted) for installation remote from an appliance. When the operating performance characteristics of the thermostat can be affected by the separate components, such as power supply, transformer, and valve(s), the thermostat is to be tested as part of a complete system. Compliance of a device with this Standard does not imply that such device is acceptable for use on gas appliances without supplemental tests with the device applied to the particular appliance design. 

1.2 An accessory incorporated as an integral part of a thermostat is to comply with all provisions of the applicable standard for such a device. 

1.3 All references to psi throughout this Standard are considered gauge pressures, unless otherwise specified. 

1.4 In this Standard, "shall" is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the Standard; "should" is used to express a recommendation or that which is advised but not required; and "may" is used to express an option or that which is permissible within the limits of the Standard. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application. 

1.5 The values given in imperial units are the units of record for the purposes of this Standard. The values given in parentheses are for information and comparison only. Note: See Annex B.