Vaisala Oyj Humidity and Temperature Transmitter HMT338

Press the ADJ button on the motherboard to open the ADJUSTMENT MENU

Wait for the probe to reach ambient temperature if using a warmed probe

Select ►Adjust T measurement, press ►key

Remove the filter from the probe and insert the probe into the reference temperature

Wait at least 30 minutes for the sensor to stabilize

Follow the stabilization from the GRAPH display

Relay Activation Using Module Push Buttons

Activate relays using module push buttons

Is the LED lit for the activated relay?

Relay Testing Using Display/Keypad

Open the MAIN MENU by pressing any of the arrow buttons

Select System and press the ►arrow button

Select Diagnostics and press the ►arrow button

Select Relay tests and press the ►arrow button

Select Invert relay 1 and press TEST

Carry out the chemical purge (if available). LiCl reference.

Press the ADJ button on the motherboard to open the adjustment mode.

Remove the filter from the probe and insert the probe into a measurement hole of the 11 % RH (LiCl) in the humidity calibrator HMK15.

Wait at least 30 minutes for the sensor to stabilize.

Is the indicator LED lit continuously?

Press the button LiCl~11% to adjust the 11 % RH condition.

Press the ADJ button to open the adjustment mode for NaCl reference.

Insert the probe into a measurement hole of the 75 % RH (NaCl) reference chamber of the humidity calibrator HMK15.

Verify sensor type compatibility

Does the transmitter have the chemical purge and/or warmed probe option?

Remove the filter from the probe

Remove the damaged sensor and insert a new one

Handle the new sensor by the plastic socket

Ensure the sensor plate is not touched

Attach a new filter on the probe

Loosen the filter by turning it counter-clockwise

Remove the filter from the probe

Install a new filter on the probe

Order new filters from Vaisala if needed