If your wax warmer gives off very little fragrance even with fresh wax, check the device and the room before blaming the melt. A weak result can come from the wrong replacement bulb, a poorly seated dish, a large space, or a fragrance that is naturally subtle.
With the warmer off and cool, confirm that its dish is correctly positioned and that the bulb, if it uses one, matches the manufacturer's specification. A bulb that fits the socket is not necessarily the right bulb. Follow the instructions for cleaning residue from the dish and using any liner.
Turn it on as directed and allow normal warming time. Observe whether the wax melts as expected; do not touch hot wax to test its temperature. If the warmer does not heat normally or appears damaged, stop using it and consult its maker.
Use a fresh portion of a familiar melt and keep the amount consistent. If the same warmer previously worked well, consider what changed: the scent, bulb, location, liner, room temperature, or amount of wax.
Next, consider the room. An open living area gives fragrance much more space to disperse than a small enclosed office. Strong drafts can also change where you notice it. Try another suitable location after the warmer has cooled, rather than moving it full of hot wax.
If the warmer operates normally but several fresh scents still perform poorly, ask the wax maker or warmer manufacturer about compatibility. Do not alter the appliance, install a more powerful bulb, or add another heat source. A different approved setup is more useful than forcing the current one beyond its design.