Abstract: A proportional control gas valve includes a valve body formed with an inlet having a first orifice, a first chamber communication with the inlet through the orifice, a second chamber formed with a balancing orifice and a second orifice, a third chamber in communication with the first chamber through the balancing orifice, a fourth chamber in communication with the first chamber via the second orifice, a fifth chamber in communication with the fourth chamber, and an outlet in communication with the fifth chamber, a solenoid assembly mounted in the first chamber for controlling gas flowing from the first chamber to the fourth chamber via the second orifice, a main diaphragm arranged between the inlet and the third chamber, a valve spring mounted under the main diaphragm and urging the main diaphragm to move upwardly to close a passage from the inlet to the outlet, a regulation diaphragm mounted inside the fifth chamber, a regulation spring mounted on the regulation diaphragm, an adjust stem connected with the r