CSA ANSI Z21.23 pdf free download
CSA ANSI Z21.23 pdf free download.American National Standard For Gas Appliance Thermostats .
1.2.4
For electric type thermostats, the manufacturer shall specify the electrical ratings desired for each model submitted.
1.2.5
For electric type thermostats, the manufacturer may furnish a test fixture which simulates the control characteristics of an appliance and any necessary additional components that, with the thermostat, constitute a complete control system. This equipment shall be used to test for calibration accuracy as specified in 2.4, Accuracy of Temperature Set Point, and for additional performance tests as specified in Part II of this standard.
1.2.6
Any operating mechanism, such as the thermostatic valve mechanism, susceptible to mechanical damage which could result in faulty or unsafe operation, shall be protected by a substantial enclosure so as to prevent interference with the safe operation of the device.
1.2.7
When an integral gas valve type thermostat is constructed so that the use of an adapter is necessary to permit pipe or semirigid gas tubing connection to be made, the adapter(s) furnished by the manufacturer shall be used in these tests.
1.2.8
The construction of thermostats shall be such that they will not show signs of becoming bent, warped, broken or defective so as to prevent their continued compliance with this standard.
1.2.9
The construction of parts and materials used that are not covered by this standard shall be in accordance with reasonable concepts of safety, substantiality and durability.
All specifications as to construction set forth herein may be satisfied by the construction actually prescribed or such other construction as will provide at least equivalent performance.
1.2.10
Thermostat valve bodies shall be constructed of materials having melting points of at least 800°F (427°C).
1.2.11
A thermostat in which a nonmetallic flexible diaphragm constitutes the only gas seal shall have the atmospheric side of the diaphragm enclosed to limit the leakage to atmosphere in the event of diaphragm rupture to not more than 1.0 ft3/hr (7.87 cm3/s) of 1.53 specific gravity gas at 11 .0 in wc (2.74 kPa) pressure, or shall be provided with means for venting the gas in the event of diaphragm rupture.
1.2.12
A thermostat in which a metallic flexible diaphragm constitutes the only gas seal shall have the atmospheric side of the diaphragm protected to prevent accidental damage to the diaphragm.
1.2.13
An electric type thermostat which is provided with an “off” position shall incorporate a positive means to prevent closing of its contacts at a temperature of -35°F (-37°C) when in the “off” position.
1.2.14
A device involving electronic control circuits shall be investigated under conditions of actual service to determine if it complies with all applicable standards and is otherwise suitable for its intended application.
1.4 Connections
1.4.1
When for connection to pipe, the inlet, outlet, pilot or other connections shall be provided with cleanly cut taper threads in accordance with the Standard for Pipe Threads, Genera! Purpose (Inch), ANSI/ASME 81.20.1.
1.4.2
Pipe thread length and length-to-shoulder dimensions shall not be less than as shown in Table I, Minimum
Thread Length and Length to Shoulder.
1.4.3
Inlet and outlet gas connections of an integral gas valve thermostat shall be designed so that when a pipe that is threaded two threads beyond standard size (for the size in question) is run into the threaded portion of a valve body, it will not adversely affect the operation of the valve.
1.4.4
When for connection to semirigid tubing, the connection together with the fittings used thereon shall be in accordance with or be inter-changeable with the fittings described in Part I, SAE Handbook.CSA ANSI Z21.23 pdf download.
