Dwyer 670 - Manual (Page 13)

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2.1 Quick Start Installation
Follow the instructions below for installing and commissioning the unit:
Before connecting the unit it is important to decide on the type of calibration that is to be used on the
installation. The two methods are described in section 1.2 Alarm Configuration/Calibration.
1. Fit the alarm to the Fume Hood using the cut-out details provided with the unit.
2. Plug in the power adapter to a 120V AC power socket and connect the flying lead to the
alarm unit - see typical connection diagram on page 6.
3. Power up the unit and wait at least 30 secs while the sensor temperature stabilizes.
During this time the Red & Green LEDs will both be on (not flashing).
If the unit has not been previously calibrated the Red & Green LEDs will begin to flash
on/off at the end of the 30 sec start up time delay but the audible alarm will not sound.
If the alarm has been calibrated it will go into normal operation.
4. Calibration:
Single Point Calibration (with CAL jumper on PCB connected).
a. Open the Sash to the normal operating height and adjust the face velocity to the
Low Air alarm value using a calibrated instrument to check the value.
b. Press and hold the Enter button for 5 secs to go into the Calibration mode. This is
indicated by both Red and Green LEDS flashing on/off together will the audible
alarm sounding (‘Beep’ on/off 4 times every 1 sec).
c. To initiate the alarm point calibration press and hold the ENTER and the SET
button at the same time. The unit will then sample the airflow for a 5 sec period
during which time the Green LED goes off and the Red LED flashes on/off. The
audible alarm continues to sound during this period and if the sampling is
successful will give a two tone beep at the end of the period and the unit will then
go automatically into the Run mode.
If the buttons are released during the sampling period or if the airflow is fluctuating
more than the pre-set value the audible alarm will give a lower frequency buzzing
sound for a short period and then go back into the calibration mode. If this occurs
re-press the ENTER and SET buttons to repeat the airflow sampling.
d. When complete re-set the airflow to the normal value and the unit will go to the
Safe running condition with the Green LED on.
The unit will now function and go into the ALARM condition if the Fume Hood
face velocity falls below the alarm value.
Use this method if the alarm is connected directly to the extract duct via the
adaptors and 1/4˝ tube.
AV-670:B-32 10/1/09 2:20 PM Page 13