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17.4.1 Stall High Threshold Setting
– Static Method
In Diagnostic Mode, press the [MODE] key repeatedly until the “Pump” screen is displayed.
Shown are the Stall High and Stall Low values. “High” should be highlighted. Press [Y/+] to
select the Stall High (high-speed) value.
The Idle value (shown as a value for “I”) should be 150 to 250. Record the value.
Block the inlet, and record the value after it goes up.
The blocked value minus the Idle (Unblocked) value should be greater than 100 counts:
(Blocked value – Unblocked value) > 100.
If it is greater than 100, then the pump is working correctly and tubing leading from the inlet
is not leaking.
To set the Stall High value, first add the Blocked and Unblocked values and divide by 2:
(Blocked value + Unblocked value) / 2 = correct Stall High value.
Then, using the [Y/+] and [N/-] keys, set the Stall High value to this number.
17.4.2 Verifying the Stall High Setting
Exit Diagnostic Mode. In Normal Mode, with the pump at high speed, block the inlet. The pump
should stall after a few seconds, sending the instrument into alarm. This tells you that the pump’s
Stall Low setting is correct.
If the gas inlet is blocked but the pump does not shut down, or the pump shuts down too
easily with a slight blockage, the pump stall threshold value may be set too high or too low.
If the pump does not stall or send the instrument into alarm, then there may be a leak in the
gas inlet or the pump is weak or defective and should be replaced.
17.4.3 Stall Low Threshold Setting - Static
In Diagnostic Mode, press the [MODE] key until the “Pump” screen is displayed. Shown are the
Stall High and Stall Low values. “Low” should be highlighted. Press [Y/+] to select the Stall
Low (low-speed) value.
The Idle (shown as a value for “I”) value should be 100 to 200. Record the value.
Block the inlet, and record the value after it goes up.
The blocked value minus the idle (unblocked) value should be greater than 100 counts:
(Blocked value – Unblocked value) > 100
If it is greater than 100, then the pump is working correctly and tubing leading from the inlet
is not leaking.
To set the Stall Low value, first add the blocked and unblocked values and divide by 2:
(Blocked value + Unblocked value) / 2 = correct Stall Low value
Then, using the [Y/+] and [N/-] keys, set the Stall Low value to this number.