TOMOON General 990-53 Solenoid Valve Assembly Water Inlet Valve Humidifier Filters
This is a 24 volt, AC electrically-operated valve that turns the water on and off to your humidifier. Preinstalled inside of the valve is a strainer screen, which filters the water before it passes through the valve, catching things like sand and dirt which could otherwise cause blockage. This valve needs to be replaced about every ten years, or more often if it fails and is stuck open or closed. 
(Note: This valve operates on 24 volts, however some units are equipped with a 115 volt solenoid valve. Look closely at your old one to see what voltage it is rated at before ordering this valve. This item can be mounted on the left OR right side of the humidifier.
Don't pay attention to the version, orifice size, part number or wattage printed on your old valve. The production of this item has been changed regularly so what is important is the voltage and your unit model number.
Specification:

Material: brass

Function: regulate the flow of water into humidifier

Voltage: 24 volt

Water flowing speed: 3.5 gallons per hour

Quantity: 1 piece

COMPATIBLE MODOLS:
1040 Bypass Style Humidifier 
1040L Bypass Style Humidifier 
1040LH Bypass Style Humidifier 
1040R Bypass Style Humidifier 
1042 Bypass Style Humidifier 
1042DM Bypass Style Humidifier 
1042DME Bypass Style Humidifier 
1042L Bypass Style Humidifier
1042LH Bypass Style Humidifier 
1042WSC Bypass Style Humidifier 
1137 Fan Powered Humidifier 
709 Bypass Style Humidifier 
709L Bypass Style Humidifier
709LH Bypass Style Humidifier