Positive pressure amplified gas-air valve for a low NOx premix combustion system

A furnace for use in an HVAC system, comprising:

• a premix combustion system, comprising;
• a chamber operable to receive gas and air and deliver a gas-air mix to a combustion chamber, the chamber comprising an air inlet operable to receive an air supply;
• a gas valve, the gas valve comprising a gas line extending from the gas valve to the chamber at a location downstream from the air inlet, the gas valve further comprising a gas supply inlet operable to receive gas from a gas source;
• an amplifier comprising;
• an air interface pneumatically coupled to the air supply;
• a secondary interface proximate the air interface and pneumatically coupled to a secondary location in the HVAC system;
• and a regulator coupled to the amplifier and to the gas valve, wherein the amplifier is configured to detect a pressure differential between the air supply and the secondary location, and to cause the regulator coupled to the gas valve to apply an amplified pressure to gas in the gas line;
• one or more heat exchangers operable to receive combusted gas-air mix from the combustion chamber;
• one or more inducers operable to induce the flow of combusted gas-air mix through the one or more heat exchangers;
• one or more blowers operable to direct air flow across the one or more heat exchangers;
• and an exhaust operable to direct combusted gas-air mix from the one or more heat exchangers to an exhaust vent.

A method of operating a furnace in an HVAC system, comprising:

• providing a premix chamber configured to receive an air supply and a gas supply and to supply a gas-air mix to a combustion chamber;
• providing a gas valve comprising a gas supply inlet configured to receive the gas supply from a gas source and a gas line configured to deliver the gas supply to the premix chamber;
• receiving the air supply in the premix chamber at an air inlet;
• receiving the gas supply in the premix chamber from the gas line connected to the premix chamber downstream of the air inlet;
• providing an amplifier operable to detect a pressure differential between a first interface and a second interface, coupling the amplifier to the regulator and further operable to apply a pressure differential to the gas supply in the gas line;
• coupling the first interface pneumatically to the air supply;
• coupling the second interface pneumatically to a secondary location in the HVAC system;
• receiving the gas-air mix in the combustion chamber;
• igniting the gas-air mix in the combustion chamber;
• and providing the ignited gas-air mix to another component of the furnace.