I have a Vulcan 903 ducted heating system and the fan seems to be running when it is not turned on could this be because the house is to hot?

Yes, it's possible that the fan in your Vulcan 903 ducted heating system is running due to the temperature in your house being too hot. Many ducted heating systems have a fan that operates to circulate air even when the heating is not actively engaged, especially if the thermostat detects a higher ambient temperature. Additionally, it might be a feature of the system to help with air circulation or to prevent overheating. If the fan runs excessively or you have concerns, consider checking the thermostat settings or consulting a technician for a thorough inspection.