The Gas Shed has forced convection, with a vane switch on the fan. The idea is that if the fan stops the switch will open and give a fault. A strong gust in the right direction will push back on the fan exhaust and the vane switch will open momentarily, not long enough for the gas system to shutdown. Also, sometimes the wind will push back on the gas exhaust and the pressure increase in the exhaust line will trip the gas pressure alarm on the FPP system. We have had such problems in the past. Chuck Long went out to check it out.