The GeneralAire 7538 is the correct replacement fill valve assembly for the following humidifier models:
The GeneralAire 35-3 Humidifier Fill Valve Assembly is a replacement fill/tempering valve assembly for the GeneralAire Elite Steam DS35 and RS35 Humidifier models. This 35-3 fill valve assembly attaches near the bottom of the Elite Steam humidifier model on the opposite side of the drain valve assembly and below the steam cylinder. The fill valve opens to allow water to enter the cylinder and then closes when the desire current is reached, which also allows the unit to warm the water and produce steam.
When your humidifier fills with water but does not produce any of the desired steam, check to see if the strainer of your fill valve is clogged because it might need to be cleaned or replaced.
GeneralAire 35-3 Humidifier Fill Valve Assembly specifications: