Vornado heaters use proprietary parts, so parts made by other brands are unlikely to work. However, small electrical components inside the unit might be replaceable with standard electrical components.
Central heating and cooling systems often use parts shared between brands, and some manufacturers own multiple brands that might share parts. This compatibility lowers the cost of ownership and allows third-party manufacturers to sell parts for units intended to last for decades. Vornado heaters, on the other hand, are designed to be compact and simple to operate, so most parts are designed to work only with Vornado models. However, small electrical parts inside the unit, such as resistors and capacitors, can often be soldered into place should they break.