Method and Controller for Operating a Gas Burner Appliance

Abstract

Method for operating a gas burner appliance ( 10 ). the gas burner appliance ( 10 ) comprising: a combustion chamber ( 11 ) in which a defined gas/air mixture is combusted. a mixing device ( 23 ) to provide said gas/air mixture. a gas safety valve unit ( 19 ) assigned to the gas duct ( 16 ) to open or close the gas duct ( 16 ) having a first gas safety valve ( 19 a ) and a second gas safety valve ( 19 b ) positioned downstream of the first gas safety valve ( 19 a ). a gas flow modulator ( 18 ) assigned to the gas duct ( 16 ), an electrical or electronic absolute pressure sensor ( 21 ) positioned downstream of the first gas safety valve ( 19 a ). wherein the gas burner appliance ( 10 ) goes into lockout state if a defined number of burner-start-ups of the gas burner appliance ( 10 ) failed. namely did not result into a combustion, and wherein the gas burner appliance ( 10 ) is operated by executing the following steps to provide an electrical or electronic pressure-switch functionality: Before each burner-start-up of the gas burner appliance ( 10 ) measuring a first absolute pressure by the absolute pressure sensor ( 21 ) when the first gas safety valve ( 19 a ) is closed. During each burner-start-up of the gas burner appliance ( 10 ) measuring a second absolute pressure by the absolute pressure sensor ( 21 ) when the first gas safety valve ( 19 a ) is opened, determining a pressure difference between the first and second absolute pressure, and comparing the pressure difference with a threshold. A lockout of gas burner appliance ( 10 ) is allowed or prevented on basis of the comparison of the pressure difference with the threshold.

1 . A method for operating a gas burner appliance, the gas burner appliance including:
 a combustion chamber being configured to combust a defined gas/air mixture,   a mixing device being configured to provide said gas/air mixture by mixing an airflow provided by an air duct with a gas flow provided by a gas duct,   a fan being configured provide the air flow or the flow of the gas/air mixture,   a gas safety valve unit assigned to the gas duct being con figured to open or close the gas duct,
 the gas safety valve unit having a first gas safety valve and a second gas safety valve positioned downstream of the first gas safety valve, 
   a gas flow modulator or gas flow regulator assigned to the gas duct being configured to keep the mixing ratio of gas and air at a defined value,   an electrical or electronic absolute pressure sensor assigned to the gas duct positioned downstream of the first gas safety valve,   wherein the gas burner appliance goes into lockout state if a de fined number of burner-start-ups of the gas burner appliance failed, namely did not result into a combustion,   wherein the method comprises the following steps to provide an electrical or electronic pressure-switch functionality:
 before each burner-start-up of the gas burner appliance, measuring a first absolute pressure by the absolute pressure sensor when the first gas safety valve is closed, said first absolute pressure being representative of an ambient pressure, 
 during each burner-start-up of the gas burner appliance:
 measuring a second absolute pressure by the absolute pressure sensor when the first gas safety valve is opened, said second absolute pressure being representative of a gas pressure, 
 determining a pressure difference between the first absolute pressure and the second absolute pressure, 
 comparing the pressure difference with a threshold, 
 
 wherein a lockout of gas burner appliance is allowed or prevented on basis of the comparison of the pressure difference with the threshold. 
   
     
     
         2 . The method of  claim 1 , wherein:
 during each burner-start-up of the gas burner appliance the second pressure is measured continuously or at a defined sampling rate,   the pressure difference between the first absolute pressure and the second absolute pressure is determined continuously or at the defined sampling rate,   the pressure difference is compared with the threshold continuously or at the defined sampling rate,   the burner-start-up is terminated if during the respective burner-start-up the pressure difference is below the threshold,   such a terminated burner-start-up is not considered as a failed burner-start-up.   
     
     
         3 . The method of  claim 1 , wherein:
 during each burner-start-up of the gas burner appliance it is monitored if the burner-start-up results into a combustion of the gas/air mixture within a defined start-up time interval, wherein
 if the burner-start-up did not result into a combustion within the defined start-up time interval and if the pressure difference determined during the start-up time interval is below the threshold, then not considering the burner-start-up is as a failed burner-start-up, 
 if the burner-start-up did not result into a combustion within the defined start-up time interval and if the pressure difference determined during the start-up time interval is above the threshold, then considering the burner-start-up as a failed burner-start-up. 
   
     
     
         4 . The method of  claim 1 , wherein:
 if the electrical or electronic absolute pressure sensor is positioned downstream of the first gas safety valve and upstream of the second gas safety valve, then
 measuring the first absolute pressure when the first gas safety valve is closed, when the second gas safety valve is opened, and when the fan is not running, 
   measuring the second absolute pressure during the burner-start-up when the first gas safety valve and the second gas safety valve are both opened and when the fan is running.   
     
     
         5 . The method of  claim 1 , wherein:
 if the electrical or electronic absolute pressure sensor is positioned downstream of the second gas safety valve, then
 measuring the first absolute pressure when the first gas safety valve is closed, when second gas safety valve is opened or closed, and when the fan is not running, 
 measuring the second absolute pressure during the burner-start-up when the first gas safety valve and the second gas safety valve are both opened and when the fan is running. 
   
     
     
         6 . The method of  claim 1 , wherein:
 if the first gas safety valve and the second gas safety valve can be opened and closed independently from each other, then
 measuring also before the burner-start-up of the gas burner appliance the second absolute pressure by the absolute pressure sensor when the first gas safety valve is opened, when the second gas safety valve is closed and when the fan is not running, 
 determining the pressure difference between the first absolute pressure and the second absolute pressure, 
 comparing the pressure difference with the threshold, wherein the burner-start-up is prevented when the pressure difference is below the threshold, 
 wherein the burner-start-up is allowed when the pressure difference is above the threshold. 
   
     
     
         7 . The method of  claim 1 , wherein:
 if a bummer-start-up has not been considered as a failed burner-start-up, then preventing a new burner-start-up of the gas burner appliance for a defined recheck time interval,   executing again the above steps providing the electrical or electronic pressure-switch functionality after the defined recheck time interval is expired.   
     
     
         8 . The method of  claim 1 , wherein:
 if the burner-start-up results into a combustion, then
 measuring during a regular combustion mode the second pressure continuously or at a defined sampling rate, 
 determining during the regular combustion mode the pressure difference between the first absolute pressure and the second absolute pressure continuously or at the defined sampling rate during combustion, and 
 comparing during the regular combustion mode the pressure difference with the threshold continuously or at the defined sampling rate, 
   if during combustion the pressure difference drops below the threshold, then terminating the combustion.   
     
     
         9 . A controller of a gas burner appliance for operating the gas burner appliance,
 the controller is configured to provide an electrical or electronic pressure-switch functionality by executing the following steps:   before each burner-start-up of the gas burner appliance, measure a first absolute pressure by an absolute pressure sensor assigned to a gas duct when a first gas safety valve assigned to the gas duct is closed, said first absolute pressure being representative of an ambient pressure,   during each burner-start-up of the gas burner appliance:
 measure a second absolute pressure by the absolute pressure sensor when at least the first gas safety valve is opened, said second absolute pressure being representative of a gas pressure, 
 determine a pressure difference between the first absolute pressure and the second absolute pressure, 
 compare the pressure difference with a threshold, 
   allow or prevent a lockout of gas burner appliance on basis of the comparison of the pressure difference with the threshold.   
     
     
         10 . The controller of  claim 9 , wherein:
 the controller is configured to operate the gas burner appliance according to the method of  claim 1 .   
     
     
         11 . The method of  claim 2 , wherein:
 if the first gas safety valve and the second gas safety valve can be opened and closed independently from each other, then
 measuring also before the burner-start-up of the gas burner appliance the second absolute pressure by the absolute pressure sensor when the first gas safety valve is opened, when the second gas safety valve is closed and when the fan is not running, 
 determining the pressure difference between the first absolute pressure and the second absolute pressure, 
 comparing the pressure difference with the threshold, wherein the burner-start-up is prevented when the pressure difference is below the threshold, 
   wherein the burner-start-up is allowed when the pressure difference is above the threshold.   
     
     
         12 . The method of  claim 3 , wherein:
 if the first gas safety valve and the second gas safety valve can be opened and closed independently from each other, then
 measuring also before the burner-start-up of the gas burner appliance the second absolute pressure by the absolute pressure sensor when the first gas safety valve is opened, when the second gas safety valve is closed and when the fan is not running, 
 determining the pressure difference between the first absolute pressure and the second absolute pressure, 
 comparing the pressure difference with the threshold, wherein the burner-start-up is prevented when the pressure difference is below the threshold, 
   wherein the burner-start-up is allowed when the pressure difference is above the threshold.   
     
     
         13 . The method of  claim 4 , wherein:
 if the first gas safety valve and the second gas safety valve can be opened and closed independently from each other, then
 measuring also before the burner-start-up of the gas burner appliance the second absolute pressure by the absolute pressure sensor when the first gas safety valve is opened, when the second gas safety valve is closed and when the fan is not running, 
 determining the pressure difference between the first absolute pressure and the second absolute pressure, 
 comparing the pressure difference with the threshold, wherein the burner-start-up is prevented when the pressure difference is below the threshold, wherein the burner-start-up is allowed when the pressure difference is above the threshold. 
   
     
     
         14 . The method of  claim 5 , wherein:
 if the first gas safety valve and the second gas safety valve can be opened and closed independently from each other, then
 measuring also before the burner-start-up of the gas burner appliance the second absolute pressure by the absolute pressure sensor when the first gas safety valve is opened, when the second gas safety valve is closed and when the fan is not running, 
 determining the pressure difference between the first absolute pressure and the second absolute pressure, 
 comparing the pressure difference with the threshold, wherein the burner-start-up is prevented when the pressure difference is below the threshold, 
   wherein the burner-start-up is allowed when the pressure difference is above the threshold.   
     
     
         15 . The method of  claim 2 , wherein:
 if the burner-start-up results into a combustion, then
 measuring during a regular combustion mode the second pressure continuously or at a defined sampling rate, 
 determining during the regular combustion mode the pressure difference between the first absolute pressure and the second absolute pressure continuously or at the defined sampling rate during combustion, and 
 comparing during the regular combustion mode the pressure difference with the threshold continuously or at the defined sampling rate, 
   if during combustion the pressure difference drops below the threshold, then terminating the combustion.   
     
     
         16 . The method of  claim 3 , wherein:
 if the burner-start-up results into a combustion, then
 measuring during a regular combustion mode the second pressure continuously or at a defined sampling rate, 
 determining during the regular combustion mode the pressure difference between the first absolute pressure and the second absolute pressure continuously or at the defined sampling rate during combustion, and 
 comparing during the regular combustion mode the pressure difference with the threshold continuously or at the defined sampling rate, 
   if during combustion the pressure difference drops below the threshold, then terminating the combustion.   
     
     
         17 . The method of  claim 4 , wherein:
 if the burner-start-up results into a combustion, then
 measuring during a regular combustion mode the second pressure continuously or at a defined sampling rate, 
 determining during the regular combustion mode the pressure difference between the first absolute pressure and the second absolute pressure continuously or at the defined sampling rate during combustion, and 
 comparing during the regular combustion mode the pressure difference with the threshold continuously or at the defined sampling rate, 
   if during combustion the pressure difference drops below the threshold, then terminating the combustion.   
     
     
         18 . The method of  claim 5 , wherein:
 if the burner-start-up results into a combustion, then
 measuring during a regular combustion mode the second pressure continuously or at a defined sampling rate, 
 determining during the regular combustion mode the pressure difference between the first absolute pressure and the second absolute pressure continuously or at the defined sampling rate during combustion, and 
 comparing during the regular combustion mode the pressure difference with the threshold continuously or at the defined sampling rate, 
   if during combustion the pressure difference drops below the threshold, then terminating the combustion.   
     
     
         19 . The method of  claim 6 , wherein:
 if the burner-start-up results into a combustion, then
 measuring during a regular combustion mode the second pressure continuously or at a defined sampling rate, 
 determining during the regular combustion mode the pressure difference between the first absolute pressure and the second absolute pressure continuously or at the defined sampling rate during combustion, and 
 comparing during the regular combustion mode the pressure difference with the threshold continuously or at the defined sampling rate, 
   if during combustion the pressure difference drops below the threshold, then terminating the combustion.   
     
     
         20 . The method of  claim 7 , wherein:
 if the burner-start-up results into a combustion, then
 measuring during a regular combustion mode the second pressure continuously or at a defined sampling rate, 
 determining during the regular combustion mode the pressure difference between the first absolute pressure and the second absolute pressure continuously or at the defined sampling rate during combustion, and 
 comparing during the regular combustion mode the pressure difference with the threshold continuously or at the defined sampling rate, 
   if during combustion the pressure difference drops below the threshold, then terminating the combustion.