Certain embodiments of a nozzle are configured to dispense a first gas, liquid, or combination thereof at a first pressure in a first mode of operation and dispense a second gas, liquid, or combination thereof at a second pressure in a second mode of operation. In some embodiments, the nozzle is integrated in a heat-producing device, such as, for example, a heater, a fireplace, or a stove. In some embodiments, the heat-producing device including the nozzle can operate with a first combustible fuel at a first pressure, or alternatively, can operate with a second combustible fuel at a second pressure. In some embodiments, the nozzle is used in applications other than heat-producing devices.