Intermittent pilot ignition gas valve having protection against negative pressure for internal diaphragms

A gas valve for an intermittent pilot ignition system, comprising:

• a valve housing comprising a first fluid pathway between an upstream inlet port and a downstream outlet port and a second fluid pathway between the upstream inlet port and a downstream pilot port;
• a first diaphragm disposed in the first fluid pathway between the upstream inlet port and the downstream outlet port, the first diaphragm being biased in a first closed position;
• a second diaphragm disposed in the first fluid pathway between the upstream inlet port and the downstream outlet port, the second diaphragm being biased in a second closed position;
• a first check valve disposed in the second fluid pathway, the first check valve positioned in a first flow passage between a first side of the first diaphragm and a second side of the first diaphragm;
• and
• a second check valve disposed in the second fluid pathway, the second check valve positioned in a second flow passage downstream of the first flow passage and proximal to the pilot port;
• wherein the first check valve and the second check valve are configured to prevent the first diaphragm and the second diaphragm from opening under a negative pressure of at least 26″ W.C.;
• and
• wherein flow of gas through the first fluid pathway from the upstream inlet port to the downstream outlet port requires a positive gas pressure sufficient to open both of the first diaphragm from the first closed position and the second diaphragm from the second closed position.