Adjusting the "Stainless Steel" - Control Valve
Your instrument is fitted with either a Brass or Stainless Steel
Control Valve. The procedure to make this adjustment is similar
but requires a different tool. Look at the Control Valve on your
instrument. If it is made of Stainless Steel - use this tutorial
if it is made of Brass - click here for
another tutorial.
Click here to
watch a "Youtube" video of this tutorial
The Control Valve is the valve that directs the flow of nitrogen from
CHAMBER / OFF / EXHAUST.
This valve will require periodic adjustment. If a leak is in the
control
valve, the symptoms are generally a continual flow of gas into the
chamber
even while the instrument is in the "OFF" position. To correct
this, follow the instructions below:
With the Stainless Steel valve you will need two tools to make the
adjustment. These tools were provided originally with your
instrument. If you have misplaced it you can purchase
a replacement from PMS Instrument. The top is a 11/32 inch
Combination Wrench and the bottom is a 3/32 inch Allen Key.
1. Connect instrument to a supply tank. Remove lid of
chamber
and turn valve to the "OFF" or "EXHAUST" position.
Listen
for gas leak. (Make sure that you are in a quiet environment
that allows you to detect when the gas hiss stops).
2. Use the allen key to loosen the set
screw
in black handle of the control valve. Lift the handle straight up
to remove.
3. Using the box end of the combination wrench, slowly tighten the
packing gland nut.
Caution: Do not over tighten the valve
packing, as permanent damage will result. Over tightening can
additionally make
the valve too tight to function normally.
4. Rotate wrench clockwise until the gas leak can no longer be
heard. Remove wrench and reinstall
the black handle.
Note: If the instrument is used over a wide range of temperatures,
some
adjustment may be needed due to thermal expansion within the valve;
this
is normal.
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