We ship worldwide — Singapore, Australia, Malaysia, Indonesia, Philippines, India, Middle East & more

JOHNSON CONTROLS Humidistat: Surface Mount - Humidifier & Dehumidifier Controls
JOHNSON CONTROLSHumidifier & Dehumidifier Controls

JOHNSON CONTROLS Humidistat: Surface Mount

The JOHNSON CONTROLS Humidistat (MPN W42AA-1C) is a surface-mount humidifier and dehumidifier control. It operates on an input voltage of 120/240V AC and does not include an outdoor temperature sensor.

SKU 3G-OTH-67470

Also listed as: W42AA1C · W42AA 1C

Brand
JOHNSON CONTROLS
Item
Humidistat: Surface Mount
Category
Humidifier & Dehumidifier Controls
Available to Order
Trade pricing by quote — replies within 24h
Qty
WhatsApp an engineerMessage via Telegram
No account needed — your quote request goes straight to our engineers. A free account lets you track quotes and re-order faster.
Worldwide Shipping
Air & sea freight
Datasheet on Request
Technical specs
1-Day Quote
Replies within 24h

Local availability & support

Delivery
Worldwide DHL shipping from Singapore; 7–14 business days door-to-door for most destinations.
Payment
Invoicing in USD. Bank transfer (SWIFT) and corporate PO accepted.

Technical Specifications

JOHNSON CONTROLS
Manufacturer Part Number
W42AA-1C
Type
Dehumidifier Control Compatible / Humidifier Control Compatible
Product Type
Humidistat
Input Voltage
120/240V AC
Mounting Location
Surface Mount
Outdoor Temperature Sensor
No

Technical Documents

No technical documents available for this product.
Request documentation
Not sure this is the right part? Get a recommendation.

Need installation or engineering help?

Installation, commissioning, maintenance plans, system design, and bundled product + service quotes — one team handles the full scope.
Talk to an engineer

Ask a question

JOHNSON CONTROLS Products
3G Electric (S) Pte. Ltd. — Singapore

Product Description

The JOHNSON CONTROLS Humidistat (MPN W42AA-1C) is a surface-mount humidifier and dehumidifier control. It operates on an input voltage of 120/240V AC and does not include an outdoor temperature sensor.

Frequently Asked Questions

What is the JOHNSON CONTROLS W42AA-1C humidistat used for?

The JOHNSON CONTROLS W42AA-1C is a surface-mount humidistat used to control humidifiers and dehumidifiers in commercial or industrial HVAC systems. It helps maintain desired humidity levels by switching equipment on or off based on the sensed relative humidity.

What are the specifications of the JOHNSON CONTROLS W42AA-1C humidistat?

The JOHNSON CONTROLS W42AA-1C is a surface-mount humidistat with an input voltage of 120/240V AC. It is compatible with both humidifier and dehumidifier controls and does not include an outdoor temperature sensor. The manufacturer part number is W42AA-1C.

Where to buy the JOHNSON CONTROLS W42AA-1C humidistat worldwide?

You can source the JOHNSON CONTROLS W42AA-1C humidistat through 3G Electric, a global industrial equipment distributor. We handle full logistics, customs clearance, and delivery to worldwide destinations. Contact us for availability and lead time.

How to install a JOHNSON CONTROLS W42AA-1C surface-mount humidistat?

Mount the JOHNSON CONTROLS W42AA-1C on a wall or vertical surface in the controlled space, away from drafts and heat sources. Connect the 120/240V AC supply per the wiring diagram. Set the humidity setpoint as needed. Always follow local electrical codes and the manufacturer's instructions.

Used in

Common applications for JOHNSON CONTROLS
Industrial refrigeration — Johnson Controls P170SA-1C dual pressure control for compressor protection in ammonia or halocarbon systems
Chiller plant automation — Johnson Controls VA7810-HGA-2 electric globe valve actuator for modulating chilled water flow in VG7000 series valves
Pneumatic HVAC retrofit — Johnson Controls T-4002-302 conversion kit for upgrading existing Robertshaw thermostats in commercial buildings
Cooling tower water management — Johnson Controls V-4332-1007 pneumatically actuated diaphragm valve for 3-way diverting of water flow
Boiler fuel oil pressure monitoring — Johnson Controls P545NCB-25C electronic lube oil pressure control with alarm for burner management systems
Process pressure sensing — Johnson Controls P599AAPS105C pressure transmitter with IP67 rating for washdown zones in food and beverage plants

JOHNSON CONTROLS Products

3G Electric supplies JOHNSON CONTROLS humidifier & dehumidifier controls. We supply genuine products with in-stock availability on common SKUs, technical documentation, commissioning support, and warranty service — worldwide.

You might also need

Burners & Combustion Pumps & Compressors Spare Parts All Products

Compatible alternatives & equivalents

Cross-referenced by specification & description
Humidity Controller: DIN Rail/Wall Mount, 120/240V AC, Dehumidifier Control Compatible, 120/240V AC (MPN S351AA-1C)
JOHNSON CONTROLS
Humidity Controller: DIN Rail/Wall Mount, 120/240V AC, Dehumidifier Control Compatible, 120/240V AC (MPN S351AA-1C)
Humidistat: Duct Mount/Wall Mount, Dehumidifier Control Compatible / Humidifier Control Compatible (MPN J10-808)
RANCO
Humidistat: Duct Mount/Wall Mount, Dehumidifier Control Compatible / Humidifier Control Compatible (MPN J10-808)
Humidity Controller: Duct Mount/Wall Mount, 24V AC, Dehumidifier Control Compatible, 24V AC (MPN H6062A1000)
HONEYWELL HOME
Humidity Controller: Duct Mount/Wall Mount, 24V AC, Dehumidifier Control Compatible, 24V AC (MPN H6062A1000)
Humidity Controller: Wall Mount, Dehumidifier Control Compatible / Humidifier Control Compatible (MPN J10-809W)
RANCO
Humidity Controller: Wall Mount, Dehumidifier Control Compatible / Humidifier Control Compatible (MPN J10-809W)
Dehumidistat: Wall Mount, Dehumidifier Control Compatible / Humidifier Control Compatible, 115V AC (MPN DH10)
TJERNLUND
Dehumidistat: Wall Mount, Dehumidifier Control Compatible / Humidifier Control Compatible, 115V AC (MPN DH10)
Humidity Controller: Wall Mount, Dehumidifier Control Compatible / Humidifier Control Compatible (MPN J10-821)
RANCO
Humidity Controller: Wall Mount, Dehumidifier Control Compatible / Humidifier Control Compatible (MPN J10-821)

More from JOHNSON CONTROLS

View all JOHNSON CONTROLS parts
Humidity Controller: DIN Rail/Surface Mount, 120/240V AC, Dehumidifier Control Compatible (MPN W351AB-2C)
JOHNSON CONTROLS
Humidity Controller: DIN Rail/Surface Mount, 120/240V AC, Dehumidifier Control Compatible (MPN W351AB-2C)
Humidistat: Wall Mount, Dehumidifier Control Compatible / Humidifier Control Compatible (MPN W43A-14C)
JOHNSON CONTROLS
Humidistat: Wall Mount, Dehumidifier Control Compatible / Humidifier Control Compatible (MPN W43A-14C)