Deciphering the WT-2000 Humidity Switch

Published: Sun Apr 11 2021

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I recently bought a couple of cheap ($25-$35CAD) RH sensor switches from China on ebay: It looks just like this but with a different model number. WT-2000

• The Upper (left) limit denotes the lower boundary RH
• The Lower (Right) limit denotes the upper boundary RH.

If you plug in a humidifier - to maintain between 20-30% RH

• set the Upper (left) boundary to 20
• set the Lower (Right) boundary to 30

The humidifier will turn on when the RH is below 20% and torn off when it hits 30%

if you plug in a fan drawing dry air to maintain between 20-30%RH

• set the Upper (left) boundary to 30
• set the Lower (Right) boundary to 20

The fan will turn on when the RH is hits 30% and turn off when it hits 20%

Programming

To set the Upper (left) boundary

1. Press the UP (left) button it will display the current setting
2. Press and hold the UP (left) button (3 sec) until it blinks.
3. while blinking press up and down to set the value.
4. wait until the blinking stops and the setting is stored.

To set the Lower (right) boundary

1. Press the DOWN (right) button it will display the current setting
2. Press and hold the DOWN (right) button (3 sec) until it blinks.
3. while blinking press up and down to set the value.
4. wait until the blinking stops and the setting is stored.

To calibrate the senor

1. Press the DOWN (right) and UP (left) simultaneously once
2. the current adjustment displays
3. while blinking press up and down to set the value. between -99% and +99%
4. wait until the blinking stops and the setting is stored.

To reset the sensor

1. Press the DOWN (right) and UP (left) simultaneously for 3 seconds
2. the sensor resets and the current RH is read and displayed

Grow tent reccomended Temp/Humidity

15 degrees is too low and dangerous. 30 is too hot and dangerous

Phase	Temp Day	Temp Night	RH
germination/propagation	20-30	20-30	70%
vegetative	20-30	17-20	40-60%
flowering	18-26	17-20	40-50%