Graco 235531 Instructions Manual page 13

Maintenance – Pulse Meter
WARNING
ELECTRIC SHOCK HAZARD
To reduce the risk of serious injury, fol-
low the Shutdown Procedure on page
12 before servicing the pulse meter.
CAUTION
To avoid damaging the electronic components of the
pulse meter module (1):
1. Do not lay anything on the pulse module.
2. If you lay the pulse module down, make sure the
open side faces up.
3. Do not twist or force the parts. Align parts prop-
erly as instructed.
To Replace the Complete Pulse Meter
1. Follow the Shutdown Procedure on page 12.
2. Disconnect the cable from the pulse module,
taking note of the wiring polarity.
3. Remove the old pulse meter and install the new
one, observing the original wiring polarity.
To Replace the Electronic Pulse Module
1. Follow the Shutdown Procedure on page 12.
2. Disconnect the cable from the pulse module,
taking note of the wiring polarity.
3. Remove the screws. Lift off the pulse module.
4. Install a new pulse module (1). Align the notches
on the underside of the pulse module with the
cutaways in the top of the metering unit. Use the
new screws and torque them oppositely and
evenly to 10–12 in-lb (1.2–1.4 NSm). See Fig. 5.
5. Connect the pulse module wires to the cable,
observing the original wiring polarity.
To Replace the Metering Unit
1. Follow the Shutdown Procedure on page 12.
2. Remove the screws. Lift off the pulse module.
3. Remove the old metering unit.
4. Install a new metering unit (2). Align the notches
on the underside of the pulse module with the
cutaways in the top of the metering unit. Use the
new screws and torque them oppositely and
evenly to 10–12 in-lb (1.2–1.4 NSm). See Fig. 5.
Replacement screws,
included with items 1 and 2.
Torque oppositely and evenly
to 10–12 in-lb (1.2–1.4 NSm)
Fig. 5
To Verify the Accuracy of a Pulse Meter
Module
1. Use a clean, calibrated container. If using a single
container, be sure to clean it after each dispense.
2. Have pump air pressure at the lowest possible
setting for dispensing fluid.
3. Put the tip of the nozzle at the bottom of the
calibrated container.
4. If the tip of the dispense valve does not reach the
bottom of the calibrated container, use a length of
plastic tubing over the tip of the nozzle to ensure
liquid enters the container from the bottom.
5. Trigger the gun slowly so the fluid immediately
covers the tip of the dispense valve.
6. Dispense 1 quart of fluid according to the metered
display on the dispense valve.
7. Allow product to sit for 20 minutes, then compare
the actual, physical measurement in the calibrated
container to the measurement displayed on the
meter.
NOTE: The procedure above will determine if the
meter is accurately dispensing the product and mini-
mize testing errors. Some variance may occur depend-
ing on the viscosity of the fluid. If this procedure deter-
mines that the meter is not accurate, recalibrate the
meter as described in the service manual or replace
the meter or the electronics as necessary.
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