4230 Flow Meter
Section 3 Installation
3-7
3.3.4 Adjusting the Bubble
Rate
Make the initial setting of the bubble rate at the shop, rather
than at the job site. At the shop you can put the bubble line in a
container beside the flow meter and watch the rate while you
adjust it. You can, of course, set the bubble rate at the job site if
you wish, but it is easier with clean water in a clear container
beside the flow meter.
To set the bubble rate:
• Connect the flow meter to a power source and turn it on.
• Turn the valve knob all the way clockwise so no air is
escaping.
Allow some time for the system to pressurize. (The pump motor
will stop running when the system reaches the correct operating
pressure.)
• Attach a bubble line to the barbed Bubble Line fitting on
the side of the case.
• For best results, use the same size bubble line you
expect to use for the installation.
Setting the bubble rate with a large ID line and then connecting
the flow meter to a small ID line will produce a much faster
bubble rate than you want. Attach the 50-foot vinyl line directly
to the barbed fitting by pressing it over the barbs. To attach the
Teflon tube, press it into a short length of silicone tubing. Then
press the other end of the silicone tube over the barbed fitting.
• Put the free end of the bubble line in a small container
of water. Set it near the flow meter so you can watch the
escaping bubbles as you turn the valve knob.
• Turn the valve slowly counterclockwise until bubbles
start coming out of the end of the tube.
• Adjust the knob to achieve a rate of one bubble per
second.
• Lock the adjustment knob by tightening the hex screw
in the handle; do not over-tighten it. You will strip the
hex screw.
Note
Always recheck the bubble rate after you have installed the
flow meter. This is particularly important if you install the bub-
ble line under several feet of water. Since you set the rate with
the bubble line under only a few inches of water, it may change
if you install the line in a deep channel.
3.3.5 Locking the Bubble
Rate
If you want to prevent accidental readjustment of the valve after
you have set it, you can lock the valve knob in place. Do this by
tightening the smaller of the two hex set screws on the valve's
handle with the 0.035" hex socket key included in the flow
meter's accessory package.
Be sure to loosen this screw before attempting to readjust the
position of the valve. Failure to do so may score the valve core or
strip the screw head.
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