Heatilator direct vent gas fireplace (standing pilot ign) was installed with new home in '02. Has seen very little use. Pilot/gas have been turned off for the last year. Started pilot recently on first attempt. It stays lit-no problems there. Turn on wall switch and the burner won't ignite. Nothing happens, no noise or gas smell. Breaker for on/off switch is good. Unit worked fine last time it was used. Any suggestions?