ANSI CSA AM Z21.17A-2008 CSA 2.7A-2008 Domestic Gas Conversion Burners (Addenda to the First Edition).pdf

1、ANSI Z21.17a-2008CSA 2.7a-2008(reaffirmed 2014)Addenda to the First Edition ofANSI Z21.17-1998 (R 2004) CSA 2.7-M98American National Standard/CSA Standard forDomestic Gas ConversionBurnersStandard DeveloperAPPROVEDCSA AMERICA INC. 8501 East Pleasant Valley RoadCleveland, Ohio 44131CANADIAN STANDARDS

2、 ASSOCIATION5060 Spectrum Way, Suite 100Mississauga, Ontario, Canada L4W 5N6Published - April 2008Copyright 2008Canadian Standards AssociationPermission is granted to republish material herein in laws or ordinances, and in regulations, administrative orders, or similar documents issued by public aut

3、horities. Those desiring permission for other republication should consult Canadian Standards Association, 5060 Specrum Way, Suite 100, Mississauga, Ontario, Canada L4W 5N6.Copyright 2008CSA America, Inc.Permission is granted to republish material herein in laws or ordinances, and in regulations, ad

4、ministrative orders, or similar documents issued by public authorities. Those desiring permission for other republication should consult CSA America, Inc., 8501 East Pleasant Valley Road, Cleveland, Ohio 44131.PrefaceThe standards set forth herein apply to the first edition of the Standard for Domes

5、tic Gas Conversion Burners, ANSI Z21.17-1998 (R 2004) CSA 2.7-1998 and supersede corresponding standards therein. Following their preparation by the supervising Technical Advisory Group, they were accepted by the American National Standards Institute (ANSI) and the Interprovincial Gas Advisory Counc

6、il (IGAC), and subsequently approved.NOTE: Changes, other than editorial, are denoted by a vertical line in the margin.January 14, 2008American National Standards Institute, Inc.April 8, 2008Interprovincial Advisory Council Effective in Canada November 1, 2009IGAC1Addenda to American National Standa

7、rd/CSA Standard for Domestic Gas Conversion Burners Part I: Construction1.9 Automatic Gas Ignition Systems And Pilot Filters1.9.2Each conversion burner shall be equipped with an automatic gas ignition system (see Part IV, Definitions). This system shall be designed to function in one of the followin

8、g manners:a. Provide for ignition of main burner gas by means of a proved pilot.If the presence of the pilot is not proved, provide for automatic shutoff of main burner gas and, on conversion burners for use with fuel gases having a specific gravity greater than 1.0, also provide for automatic shuto

9、ff of pilot burner gas.b. Provide for ignition of main burner gas using a direct ignition system which only supervises the main burner(s) flame.If the presence of the main burner flame is not proved, provide for automatic shutoff of main burner gas.In the event of main burner flame outage during an

10、operating cycle, provide for automatic shutoff of main burner gas without re-energizing the direct ignition device or provide for prompt and safe reignition of main burner gas by re-energizing the direct ignition device.c. Provide for ignition of main burner gas using a direct ignition system incorp

11、orating a proved igniter which proves that the igniter is capable of ignition prior to initiation of main burner gas flow.For systems which supervise main burner flame during an operating cycle and deenergize the igniter, provide for automatic shutoff of main burner gas in the event of main burner f

12、lame outage.2Part II: Construction2.8 Direct Ignition Systems2.8.5If the ignition system incorporates flame failure reignition, it shall be capable of reestablishing ignition and as specified in 2.8.4, in not more than 0.8 seconds following flame outage (except as specified in 2.8.6), and it shall r

13、eignite the main burner without flame flashout or damage to the conversion burner. For purposes of this test, the control manufacturers specified maximum flame failure reignition time or minimum recycle time shall be used.2.9 Proved Igniter SystemsThis section is applicable to a proved igniter syste

14、m which provides for ignition of the main burner gas.2.9.1Proved igniter systems shall comply with the applicable performance provisions of the Standard for Automatic Gas Ignition Systems and Components, ANSI Z21.20.2.9.2The proved igniter system shall effect ignition of the gas at the main burner(s

15、) when tested in accordance with the Method of Test specified in 2.9.3.2.9.3Under the conditions of voltage variation specified in the following Method of Test, the proved igniter system shall ignite main burner gas within 4 seconds after gas reaches the main burner port(s).Method of TestThe followi

16、ng voltages shall be used during conduct of this test:a. UndervoltageThe voltage to the appliance shall be adjusted to 85 percent of the appliance rating plate voltage.b. OvervoltageThe voltage to the appliance shall be adjusted to 110 percent of the appliance rating plate voltage.Under the conditio

17、ns specified in “a” and “b” above, ignition cycles shall be repeated 25 times.In each case the proved igniter system shall ignite main burner gas within 4 seconds after gas reaches the main burner port(s).2.9.4The proved igniter system shall effect ignition of the gas at the main burner(s) under the

18、 following conditions:The test shall be conducted at the normal inlet test pressure and with the appliance both hot and cold.3The proved igniter system shall be placed in operation with the igniter proving characteristics reduced to the minimum value specified by the control manufacturer. Under thes

19、e conditions the proved igniter system shall effect ignition of the gas within 4 seconds after gas reaches the burner port(s) without damage to the appliance or excessive flame flashout. While maintaining these conditions, the ignition cycle shall be repeated a total of 25 times.2.9.5For proved igni

20、ter systems which incorporate an interrupted ignition source together with main burner flame proving, the time required for the system to shut off the main burner gas supply following loss of the supervised main burner flame shall not exceed the flame failure response time and valve closing time spe

21、cified in Table V, Maximum Safety Control Timings. For purposes of this test, the control manufacturers specified maximum flame failure response time for the proved igniter system shall be used.Method of TestThe appliance shall be operated for a period of 30 minutes at normal inlet test pressure. Al

22、l gas shall then be turned off and the gas flow immediately reestablished but not ignited. The time for main burner gas to be shut off shall be recorded and shall not exceed that specified in Table V.2.9.6A proved igniter system which incorporates an interrupted ignition source together with main bu

23、rner flame proving shall not cause excessive flame flashout or damage to the appliance.For purposes of this test, the control manufacturers specified maximum flame failure response time in combination with the control manufacturers specified minimum recycle time for the proved igniter system shall b

24、e used.Method of TestThe appliance shall be instrumented with a sampling tube(s) to measure the gas-air ratio at various points in the appliance. This sampling tube(s) shall be connected to a gas-air analyzer coupled to a chart-type single-point recording potentiometer in order to produce a constant

25、 trace of the gas-air ratio at the sample point for sufficient time to allow a complete evaluation of the system. The gas-air ratio trace shall be developed with the appliance both hot and cold and with all test gases for which the appliance is tested. Supplemental natural gas test with test Gas G n

26、eed not be conducted.Unburned gas shall be allowed to flow into the appliance for the control manufacturers maximum specified flame failure response time plus the valve closing time. Immediately following shut off of the gas supply, an ignition cycle shall be initiated at normal rated voltage and co

27、ntinued until the igniter would be enerzed, as determined by the control manufacturers specified minimum recycle time.If the gas-air ratio at the time at which the igniter would be energized is below the lower combustible limit, the appliance shall be considered as complying with the provision. If t

28、his ratio is above the lower combustible limit, sufficient ignition tests shall be conducted between the time of energization of the proved igniter and when the atmosphere within the appliance returns to below the lower combustible limit, to determine that the igniter does not cause excessive flame

29、flashout or damage to the appliance.An appliance with a control system providing a purge period of 5 minutes or longer shall be considered as complying with this provision.42.9.7 For a proved igniter system which incorporates an intermittent ignition source, the time required for the gas supply to t

30、he main burner to be shut off following a failure of the supervised proved igniter shall not exceed that specified in Table V, Maximum Safety Control Timings. Method of TestThe appliance shall be operated for a period of 30 minutes at normal inlet test pressure. The proved igniter shall then be disa

31、bled. The time required for the proved igniter system to shut off the main burner gas supply shall not exceed the igniter failure response time and valve closing time specified in Table V.For purposes of this test, the control manufacturers specified maximum igniter failure response time shall be us

32、ed.(Former 2.9, Flame Spreader Temperatures through 2.13, Marking Material Adhesion and Legibility become 2.10 through 2.14 respectively.)5Part IV: DefinitionsAUTOMATIC GAS IGNITION SYSTEM. A system(s) designed to ignite and reignite an appliance burner(s). Such systems shall:1. Automatically ignite

33、 gas at the main burner, or gas at the pilot burner so that the pilot can ignite the main burner;2. Prove the presence of either the ignition source, the main burner flame, or both; and3. Automatically act to shutoff the gas supply to the main burner or to the pilot burner and the main burner, when

34、the supervised flame or ignition source is not proved.AUTOMATIC GAS IGNITION SYSTEM TIMINGS.1. Flame Failure Reignition Time. The period of time between loss of the supervised ignition source or the supervised main burner flame and attainment of the capability of the ignition means to ignite gas. Du

35、ring this time period the main burner gas supply is not shut off.2. Flame Failure Response Time. The period of time between loss of the supervised ignition source or the supervised main burner flame and the action to shut off the gas supply.3. Ignition Activation Period. The period of time between e

36、nergizing the main gas valve and deactivation of ignition means during a trial for ignition period.4. Lockout Time. The period of time between energizing the system and lockout if proof of the supervised ignition source or the supervised main burner flame is not established.5. Pilot Flame Establishi

37、ng Period. The period of time between initiation of pilot gas flow and proof of the supervised pilot flame. 6. Recycle Time. The period of time between shutoff of the gas supply following loss of the supervised ignition source or the supervised main burner flame and reactivation of the ignition sour

38、ce.7. Trial For Ignition Period. The period of time between energizing and deenergizing the gas valve if proof of the supervised flame is not established.8. Valve Sequence Period. The sum of all trial for ignition periods prior to lockout, if proof of the supervised main burner flame is not establis

39、hed.CONVERSION BURNER, GAS. A unit consisting of a burner and its controls utilizing gaseous fuels for installation in a new appliance and/or for field replacement of a burner utilizing the same fuel or another fuel.1. Atmospheric (Natural Draft) Burners. These burners rely on the natural draft thro

40、ugh the appliance to draw in the air required for combustion and therefore are not equipped with mechanical combustion air moving devices. Various burner configurations are designed to provide the required flame geometry.a. Inshot Burner. This burner fires horizontally into the combustion zone. It m

41、ay have a spreader or target plate downstream of the burner head to direct the flame.6b. Upshot Burner. This burner fires vertically with the flame being diverted by a spreader. The flame is generally circular in shape and has a uniform cross section.c. Ported Upshot Burner. This burner fires vertic

42、ally from a series drilled ports, slots or ribbons. The flame is generally uniform in height.2. Power Burners. These burners are equipped with a mechanical device, such as a fan or blower, to provide combustion air to the burner under pressure. The pressure at which air is delivered and burner desig

43、n provide the required flame geometry.a. Low-Pressure Inshot. This burner fires horizontally into the combustion zone. Combustion air is supplied at a pressure at least sufficient to overcome the resistance of the burner.b. High-Pressure Inshot. This burner fires horizontally into the combustion zon

44、e. Combustion air is supplied at a pressure sufficient to overcome the resistance of the burner and the appliance.c. Low-Pressure Upshot. This burner fires vertically into the combustion zone. The flame is generally round and symmetrical. Combustion air is supplied at a pressure at least sufficient

45、to overcome the resistance of the burner.IGNITER, PROVED. An igniter which is proven to be capable of ignition prior to initiating gas flow.Igniter Failure Response Time. The period of time between loss of the supervised proved igniter and the action to shut off the gas supply.Igniter Proving Time.

46、The period of time between energizing the igniter and achieving the proved igniter characteristic which allows gas flow.IGNITION SOURCE.1. Continuous. An ignition source which, once placed in operation, is intended to remain ignited or energized continuously until manually interrupted.2. Intermitten

47、t-Continuous. An ignition source which is ignited or energized upon appliance user initiation of the operational cycle and which remains continuously ignited or energized during the appliance use cycle. The ignition source is extinguished or deenergized when the appliance use cycle is complete.3. In

48、termittent. An ignition source which is automatically ignited or energized when an appliance is called on to operate and which remains continuously ignited or energized during each period of main burner operation. The ignition source is automatically extinguished or deenergized when each main burner

49、 operating cycle is completed.4. Intermittent-Interrupted. An ignition source which is ignited or energized upon appliance user initiation of the operational cycle and which is extinguished or deengergized after the appliance use cycle has been initiated.5. Interrupted. An ignition source which is automatically ignited or energized when an appliance is called on to operate and is automatically extinguished or deenergized during the Trial For Ignition Period. PURGE TIME. The period of time intended to allow for the dissipation of any unburned gas or residual products of combustio