Humboldt H-2786C Air Meter - Manual (Page 3)

nnmm
Operation Instructions
1. Place a representative sample of concrete in 3 equal layers,
consolidating each layer by rodding and tapping the bowl, vibration
may be substituted.
2. Using a sawing motion, strike off the excess concrete across the top
flange with the screeding tool. Wipe the flanges clean.
3. Clamp the cover on with the petcocks open.
4. Using the plastic wash bottle (supplied), inject water through one
petcock until all the air is expelled through the opposite petcock.
5. Roll the air meter on the perimeter of the base while lightly tapping
the sides to release entrapped air and to ensure complete filling.
Gently close the “hands-free” valve.
6. Pump up air to the initial pressure point, as shown for your meter,
using the super pump.
7. Wait a few seconds and stabilize the gauge needle on the “initial
pressure” line by pumping up or by loosening the bleeder cap,
whichever is necessary.
8. Close both petcocks and open the “hands-free” valve. Lightly tap
the gauge with fingertips to stabilize the gauge needle.
9. Read and record the percent of air shown on the dial.
10. Gently close the “hands-free” valve. Open the petcocks to release
the pressure. Remove the cover.
11. Clean the petcock openings, air meter and accessories with water.
12. Open the “hands-free” valve to release the pressure on the gauge.
To Check Calibration of Meter Gauge
The calibration of the meter may be checked as follows:
1. Fill the base with water.
2. Screw the short piece of straight tubing into the threaded petcock
hole on the underside of the cover. Clamp cover on the base with
the tube extending down into the water.
3. Open both petcocks, introduce water via the wash bottle through
the threaded petcock until all the air is forced out the opposite
petcock. Leave both petcocks open.
2