Compensating for Gas Applicance De-Rate at High Altitudes

Abstract

Apparatus and methods are provided for compensating for high altitude reduction in the heating capacity of a gas heating appliance, illustratively a gas-fired heating furnace. In a representative embodiment of such apparatus and methods the regulated pressure of the furnace gas valve, and the speeds of its combustion and indoor blowers, are coordinatingly increased to provide the furnace with a substantially unchanged maximum heating output despite its new higher altitude location.

1 . A method of compensating for heating output de-rating in a gas-fired heating appliance due to high altitude use thereof, the heating appliance having a regulated gas supply pressure, said method comprising the step of:
 upwardly adjusting said regulated gas supply pressure to a magnitude sufficient to provide said heating appliance with a heating capacity equal to that of the unadjusted heating appliance when disposed at a lower altitude.   
     
     
         2 . The method of  claim 1  wherein:
 said upwardly adjusting step is performed in a manner raising said regulated gas supply pressure to a magnitude greater than 3.5″ W.C. 
 
     
     
         3 . The method of  claim 1  wherein:
 said heating appliance is a gas-fired furnace. 
 
     
     
         4 . The method of  claim 1  wherein:
 said heating appliance further has a gas valve operative to provide said regulated gas supply pressure at a fixed magnitude of 3.5″ W.C., and 
 said upwardly adjusting step is performed by replacing said gas valve with a gas valve having a regulated gas supply pressure greater than 3.5″ W.C. 
 
     
     
         5 . The method of  claim 1  wherein:
 said heating appliance further has a gas valve with an adjustable regulated gas supply pressure, and 
 said upwardly adjusting step is performed by upwardly adjusting said regulated gas supply pressure of said gas valve to a magnitude greater than 3.5″ W.C. 
 
     
     
         6 . The method of  claim 5  wherein:
 said upwardly adjusting step is performed by manually adjusting said gas valve. 
 
     
     
         7 . The method of  claim 5  wherein:
 said heating appliance further has an automatic control portion, and 
 said upwardly adjusting step is performed in response to user input to said control portion of at least an altitude value. 
 
     
     
         8 . The method of  claim 7  wherein:
 said upwardly adjusting step is performed in response to user input to said automatic control portion of altitude and gas heating value magnitudes. 
 
     
     
         9 . The method of  claim 1  wherein:
 said heating appliance further has an air blower and a combustion blower. 
 
     
     
         10 . The method of  claim 9  further comprising the step of:
 upwardly adjusting the speed of said air blower to a magnitude coordinated in a predetermined manner with the upwardly adjusted regulated gas supply pressure. 
 
     
     
         11 . The method of  claim 10  wherein:
 said heating appliance further has an automatic control portion, and 
 said step of upwardly adjusting the speed of said air blower is performed in response to user input to said automatic control portion of at least an altitude value. 
 
     
     
         12 . The method of  claim 11  wherein:
 said step of upwardly adjusting the speed of said air blower is performed in response to user input to said automatic control portion of altitude and gas heating value magnitudes. 
 
     
     
         13 . The method of  claim 9  further comprising the step of:
 upwardly adjusting the speed of said combustion blower to a magnitude coordinated in a predetermined manner with the upwardly adjusted regulated gas supply pressure. 
 
     
     
         14 . The method of  claim 13  wherein:
 said heating appliance has an automatic control portion, and 
 said step of upwardly adjusting the speed of said combustion blower is performed in response to user input to said automatic control portion of at least an altitude value. 
 
     
     
         15 . The method of  claim 14  wherein:
 said step of upwardly adjusting the speed of said combustion blower is performed in response to user input to said automatic control portion of an altitude value and a gas heating value. 
 
     
     
         16 . The method of  claim 13  wherein:
 said heating appliance has an automatic control portion including pressure/electric switch apparatus, and 
 said step of upwardly adjusting the speed of said combustion blower includes the step of linking said pressure/electric switch apparatus and said combustion blower. 
 
     
     
         17 . The method of  claim 5  wherein:
 said heating appliance has an automatic control portion including pressure/electric switch apparatus, and 
 said step of adjusting said regulated gas supply pressure includes the step of pneumatically linking said pressure/electric switch apparatus and said gas valve. 
 
     
     
         18 . The method of  claim 17  wherein:
 said heating appliance further has a combustion blower, and 
 said method further comprises the step of pneumatically linking said pressure/electric switch apparatus and said combustion blower. 
 
     
     
         19 . The method of  claim 5  wherein:
 said heating appliance further has an automatic control portion including a preprogrammed microprocessor, and 
 said step of upwardly adjusting said regulated gas supply pressure includes the step of transmitting an electrical control signal from said automatic control portion to said gas valve. 
 
     
     
         20 . The method of  claim 1  wherein:
 said heating appliance has a variable speed air blower, a gas valve with an adjustable regulated gas supply pressure, and an automatic control portion having a lookup table portion, and 
 said method further comprises the steps, performed in response to user input to said automatic control portion of a signal comprising a selected appliance elevation value, of:
 outputting from said lookup table portion to said air blower an adjusted RPM value control signal, and 
 outputting from said lookup table portion to said gas valve an adjusted regulated gas supply pressure value control signal. 
 
 
     
     
         21 . An altitude adjustable gas-fired heating appliance comprising:
 an air blower for flowing air to be heated; and   a fuel gas combustion system for creating hot combustion gases and utilizing said hot combustion gases to heat said air, said fuel gas combustion system including:
 a combustion blower operative to discharge said hot combustion gases from said heating appliance, and 
 a gas supply valve with a regulated gas supply pressure which is upwardly adjustable to a magnitude sufficient to provide said heating appliance with a heating capacity equal to that of the unadjusted heating appliance when disposed at a lower altitude. 
   
     
     
         22 . The altitude adjustable gas-fired heating appliance of  claim 21  wherein:
 said regulated gas supply pressure of said gas supply valve is upwardly adjustable to a magnitude greater than 3.5″W.C. 
 
     
     
         23 . The altitude adjustable gas-fired heating appliance of  claim 21  wherein:
 said gas-fired heating appliance is a furnace. 
 
     
     
         24 . The altitude adjustable gas-fired heating appliance of  claim 21  further comprising:
 automatic control apparatus adapted to receive user input comprising an appliance altitude value and, in response to said user input, upwardly adjust said regulated gas supply pressure. 
 
     
     
         25 . The altitude adjustable gas-fired heating appliance of  claim 24  wherein:
 said automatic control apparatus is further operable, in response to said user input, to upwardly adjust the speed of said air blower. 
 
     
     
         26 . The altitude adjustable gas-fired heating appliance of  claim 24  wherein:
 said automatic control apparatus is automatically operable to upwardly adjust the speed of said combustion blower. 
 
     
     
         27 . The altitude adjustable gas-fired heating appliance of  claim 26  wherein:
 said automatic control apparatus includes pressure/electric switch apparatus pneumatically linked to said combustion blower. 
 
     
     
         28 . The altitude adjustable gas-fired heating appliance of  claim 24  wherein:
 said automatic control apparatus includes pressure/electric switch apparatus pneumatically linked to said gas supply valve. 
 
     
     
         29 . The altitude adjustable gas-fired heating appliance of  claim 28  wherein:
 said pressure/electric switch apparatus is further pneumatically linked to said combustion blower. 
 
     
     
         30 . The altitude adjustable gas-fired heating appliance of  claim 24  wherein:
 said automatic control apparatus includes a preprogrammed microprocessor and is operable to transmit an electrical control signal to said gas valve to upwardly adjust said regulated gas supply pressure. 
 
     
     
         31 . The altitude adjustable gas-fired heating appliance of  claim 21  further comprising:
 automatic control apparatus including a lookup table portion which, in response to user input to said control apparatus of at least a selected appliance elevation value, outputs to said air blower an adjusted RPM value control signal, and outputs to said gas supply valve an adjusted regulated gas supply pressure value control signal.