MEMORANDUM 

To: Carl Ad- and Kathi Epping, DOE 

Prom: Greg Rosenquist, LBNL 

Subject: Gas Range Ignition Control Systems 

Date: April 30,1998 

This memo discusses operational and safety issues pertaining to gas range ignition control systems. 

The information presented in this memo came from phone convexsations with two different stafF 

members (Joe Erdelsky and Morgan Reynolds) at Siebe Appliance Controls during the first week 

of April. Siebe Appliance Controls was recently purchased by Robershaw. The residential controls 

division of Robertshaw was moved under Siebe Appliance Controls. Robertshaw dso recently 

purchased Baton's appliance controls divisions. These former Eaton divisions were also rnoved 

under Siebe Applihce Controls, With these recent acquisitions, Robertshaw now supplies gas 

ignition control systems to approximately 70 to 80% of the gas range market. 

Ignition Safety hue for Gas Ovens 

The safety concerns for standing pilot and electronic ignition gas oven control system are virtually 

identical. nus, replacing a standing pilot ignition system with m electronically-based system does 

not create any additional safety concerns. The following provides a detailed description of both 

standing pilot and electronic ignition gas oven control system. 

Sranding Pilot Ignition 

Standing pilot control systems for gas ovens utilize what are termed dualpilot control valves. '1n the 

standby mode, the pilot's rate of consumption is approximately 150 BW, In the heuter mode, the 

pilot's rate of consumption is between 150 to 800 BNhr. When, the user selects a high oven 

temperature setting (>200°F), the pilot's rate is suddently boosted fiom its standby mode of 150 

Btulht to its highat heater mode rate of 800 BWhr. At pilot rates exceeding 300 to 600 Btu/hr, a 

safety valve opens within the main gas valve allowing gas flow to the muin burner. Once gas flows 

to the main burner, the pilot (in its heater mode) ignites the main burner. A sensing bulb, equivalent 

to a thermopile, senses whether the pilot's consumption is at a high rate (300 to 600 Btu/ht). If the 

pilot is for some masoli extinguished, the sensing bulb and its accompanying control mechanism will 

not allow gas to flow to the main bmr j&houizh gas will continue to flow to the pilot. 

If the oven themostant is set ro a low oven ~mperalwe setting (<200"F), the pilot will modulate 

(from 150 to 800 BW) along with the main burner to meet the desired oven temperatme, As just 

mentioned, the oven safety valve begins to open at rates between 300 to to Btumt, The actual rate 

which the safety valve opens depends on the control strategy that the oven manufacturer wants to 

employ. 

EE-RM-S-97-700_EERE-1997-STD-0070 COMMENT 47

900~ 

MEMORANDUM 

To: Carl Adams and Ka.thi Epping. DOE 

From: Greg Rosenquist. LBNL 

Subject: Gas Range Ignition Control Systems 

Date: April 30, 1998 

This memo discusses operational and safety issues pertaining to gas range ignition control systems. 

The infonnation presented in this memo came from phone conversations with two different staff 

members (Joe Erdelsky and Morgan Reynolds) at Siebe Appliance Controls during the first week 

of April. Siebe Appliance Controls was recently purchased by Robershaw. The residential controls 

division of Robertshaw was moved under Siebe Appliance Controls. Robertshaw also recently 

purchased Eaton's appliance controls divisions. These former Eaton divisions were also moved 

under Siebe Appliance Controls. With these recent acquisitions. Robertshaw now supplies gas 

ignition control systems to approximately 70 to 80% of the gas range market. 

Ignition Safety Issues for Gas Ovens 

The safety concerns for standing pilot and electronic ignition gas oven control systems are 'Virtually 

identical. Thus, replacing a standing pilot ignition system with an electronically-based system does 

not create any additional safety concerns. The following provides a detailed description of bOth 

standing pilot and electronic ignition gas oven control systems. 

Standing Pilot Ign;rion 

Standing pilot: control systems for gas ovens utilize what are termed du.al pilot control valves. 'In the 

strJ.n.dby mode, the pilot's rate of consumption is approximately 150 BtuIhr. In the heater mode, the 

pilot's rate of consumption is between 150 to 800 BtuJhr. When the user selects a high oven 

temperature setting (>200"F). the pilot's rate is suddently boosted from its stan4by mode of 150 

Btulhr to its highest heate,. mode rate of 800 BtuIhr. At pilot rates exceeding 300 to 600 BtuIhr, a 

safety valve opens within the main gas valve allowing gas flow to the "uz:in. bu.me,.. Once gas flows 

to the main burner, the pilot (in its heater mode) ignites the main burner. A sensing bulb, equivalent 

to a thermopile, senses whether the pilot's consumption is at a high rate (300 to 600 BtuIhr). If the 

pilot is for SOIlle reason extinguished, the sensing bulb and its accompanying control mechanism will 

not allow gas to flow to the main burner although gas will continue to flow to the pilot. 

H the oven thermostant is set to a low oven temperature setting (<200 oF). the pilot will modulate 

(from 150 to 800 BtuIbt) along with the main burner to meet the desired oven temperature. As just 

mentioned, the oven safety valve begins to open at rates between 300 to 600 Btu/hr. The actual rate 

which the safety valve opens depends on the control strategy that the oven manufacturer wants to 

employ. 

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Iffor some mason the pilot light gets extinguished, gas will continue to flow to the pilot. Depending 

on the thermostat setting, the rate of release will be any where: from 150 to 800 Btulhr. If the user 

sets the thermostat to a high temperature setring resulting in gas flow to the piloc equiv dent to its 

higbest heater mode setting (800 Btulhr), there is nothing in the control system to stop the flow of 

unburned gas to the pilot. Presumably the user will check the oven's operation once they realize the 

oven is not getting hot. But in case they do not check the oven, an 800 Btu/hr flow of unignited gas 

does not violate existing safety standards. According to ANSI Standard Z21.1, an 800 BNht 

unignited gas flow uri&in an oven does not pose a safety hazard. 

Electronic Spark-to-Pilot Ignition 

Spark-to-pilot ignition syst~ms operate very similar to standing pilot systems, Rather than utilizing 

a standing pilot, a spark ignitor is used to light the pilor (and in turn light the main burner) when the 

oven themostat is activated. Once the pilot is lit, the spark-to-pilot ignition system follows the sme 

operational procedure as described above for standing pilot systems. 

If the spatk ignition system was not able to light the pilot, like the standing pilot system, the 

maximum release of unignited gas would be at a rate of 800 BtiJhr. As stated above, this continual 

release of gas would not violate ANSI Z2 1.1 safety standards. But the continual release of gas would 

be unlikely as the audible "clicking" sound of the spark ignitor trying to light the pilot would alert 

the user that something was wrong with the ignition system. The control system utilizes a reignition 

chuit which sends a signal to the spark ignitor to try and ignite the pilot as long as the pilot is not 

lit. Presumably the user would set the thermostat in the off position to stop the "ckcbg" sound and 

prevent the flow of gas to the pilot. 

Spark Electronic Ignition Control Systems for Gas Rangtxi 

Spark electronic ignition control systems for gas rmges utilize a control module to light the 

burners at the coolnap and the ovcri, The control module for this systern utilizes what is temd a 

2+I control module. The first value, 2, represents the number of manual spark i@tors at the 

cooktop. The ignitow are kmed manual because the user must manually reset the themostat knob 

in order to refight the cooktop burners if they become extinguished. The second value in the 2+1 

control module, 2, reprasenu the number of reignition circuits in the gas range. In this case, the 

reignition circuit is for the oven and it follows the same operational procedure as just described 

above. The cooktap does not require a reignition system as tbe user has visual recognition of when 

the burners are ignited. 

Typical Non-Standfng Pilot Ignition Systems for Gas Ranges 

Spark electronic ignition control systems (for both the cooktop and oven) are typically not used in 

gas ranges. Rather, the typical non-standing pilot ignition system consists of an electric glo-bar 

ignition device for the oven and a separate electronic spark-tocbmer ignition system for the cooktop. 

For the cooktop, the spark ignition control system wit1 typically be one that uses a 2+0 control 

9669 98P OTO XVd 99:OT a3114 66/ZT/OO 

EE-RM-S-97-700_EERE-1997-STD-0070 COMMENT 47

LoOIEJ 

If for some reason the pilot light gets extinguished, gas will continue to flow to the pilot. Depending 

on the thennostal setting, the rate of release will be any where from 150 to 800 Btulhr. If the user 

sets the thermostat to a high temperature setting resulting in gas flow to the pilot equivalent to its 

highest heater mode setting (800 Btulhr), there is nothing in the control system to stop the flow of 

unburned gas to the pilot. Presumably the user will cheek the oven's operation once they realize the 

oven is not getting hot. But in case they do not check the oven, an 800 BtuIhr flow of unignited gas 

does not violate existing safety standards. According to ANSI Standard Z21.1, an 800 BtuIhr 

unignited gas flow within an oven does not pose a safety hazard. 

Electronic Spark-to-Pilot Ignition 

Spark-to-pilot ignition systems operate very similar to standing pilot systems. Rather than utilizing 

a standing pilot. a spark ignitor is used to light the pilot (and in tum light the main burner) when the 

oven thennostat is activated. Once the pilot is lit, the spark-to-pilot ignition system follows the same 

operational procedure as described above for standing pilot systems. 

If the spark ignition system was not able to light the pilot, like the standing pilot system. the 

maximum release of unignited gas would be at a rate of 800 BtuIhr. As stated above. this continual 

release of gas would not violate ANSI Z21.1 safety standards. But the continual release of gas would 

be unlikely as the audible "clicking" sound of the spark ignitor trying to light the pilot would alert 

the user that something was wrong with the ignition system. The control system utilizes a reignitioll 

circuit which sends a signal to the spark ignitor to try and ignite the pilot as long as the pilot is not 

lit. Presumably the user would set the thennostat in the off position to stop the "clicking" sound and 

prevent the flow of gas to the pilot. 

Spark Electronic Ignition Control Systems for Gas Ranges 

Spark electronic ignition control systems for gas ranges utilize a ~ control module to light the 

burners at the cooktop and the oven. The control module for this system utilizes, what is termed a 

2+1 control module. The first value. 2, represents the number of manual spark ignitors at the 

cooktop. The ignitors are termed manual because the user must manually reset the thermostat knob 

in order to relight the cooktop burners if they become extinguished. The second value in the 2+1 

control mod1l1e.l. represents the number of reignition circuits in the gas range. In this case, the 

reignition circuit is for the oven and it follows the same operational procedure as just described 

above. The cooktop does not require a reignition system as the user has visual recognition of when 

the bUrners are ignited. 

Typical Non-Standing Pilot Ignition Systems for Gas Ranges 

Spark electronic ignition control systems (for both the cooktop and oven) are typically not used in 

gas ranges. Rather. the typical non-standing pilot ignition system consists of an electric glo-bar 

ignition device for the oven and a separate electronic spark-to--bwner ignition system for the cooktop. 

For the cooktop, the spark ignition control system wUl typically be one that uses a 2+0 control 

2 

1Na1 ([V3 9669 9st 0IS XVd 9S:0I ([3M 661ZI/S0 
module. The first value, 2, represents the number of manual spark ignitors ~hile the second value, 

0, represents the number of reignition circuits. Reigntion circuits are not ded as the user bas 

visual recopition of when the burners are ignited. High-end (i.e,, more expensive) gas range 

cwktops will use ignition systems utilizing a 01-4 control moduk. As just described, the first value, 

0, represents the number of manual spark ignitors while the second value, 4, represents the number 

of spark ignitors with leigaition ckuits. Thus, if any of the gas cooktop burners become 

extinguished, the control module will send a reigntion signal to the ignitor to relight the cooktop 

burner. 

EE-RM-S-97-700_EERE-1997-STD-0070 COMMENT 47

800~ 

module. The first value, 2, represents the number of manual spark ignitors :while the second value, 

0, represents the number of reignition circuits. Reigntion circuits are not needed as the user has 

visual recognition of when the burners are ignited. High-end (i.e •• more expensive) gas range 

cooktops will use ignition systems utilizing a 0+4 control modu.le. As just described, the first value. 

0, represents the number of manual spark ignitors while the second value. 4, represents the number 

of spark ignitors with reignition circuits. Thus. if any of the gas cooktop burners become 

extinguished, the control module will send a reigntion signal to the ignitor to relight the cooktop 

burner. 

3 

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