Graco 965481, 965477, 965478 Maintenance, Checking the Ratio, Pump Lubrication Wet Cups, Bearings

Checking the Ratio

Note: The mix ratio must be checked at the normal operating fluid pressure of the pump. Most mixer manifolds provide a means for checking mix ratio that includes needle valves for adjusting the fluid pressure during the test. The following procedure is an example of how to properly check the mix ratio.

1.Open the mixer manifold and trigger your spray gun.

2.Set your operating pressure. After determining the operating pressure, release the spray gun trigger and engage the safety latch.

3.Close the mixer manifold inlet valves.

4.Slightly open the sampling valve on the secondary pump side. Slightly open the sampling valve on the primary pump side. This will prevent pressure from building up on the secondary pump, causing the relief valve to open.

5.Place a grounded waste container under the sampling valve.

6.Open the mixer manifold. Use the sampling valves to adjust the pressures to your normal operating pressures.

7.Close the mixer manifold. Put the sampling containers under the sampling valves.

8.Open the mixer manifold. Check the ratio; make sure the pressure is within 20% of your normal operating pressure. Close the mixer manifold when enough fluid has been dispensed into the sampling containers.

NOTE: If the pressure readings are not within 20% of your normal operating pressure, follow the flushing procedure on page 11, then take a sample again. If your sample ratio is incorrect, there is a problem with the sampling valves, ratio setting, or pump operation. Check the ratio setting or service the sampling valves or pump.

Maintenance

Pump Lubrication

Wet Cups

Each of the fluid cylinders has a wet cup (18) at the top that must be kept lubricated. See figure 6. The wet cups should be inspected and filled on a weekly basis, or more frequently if found to be dry. To inspect the wet cups, follow the pressure relief procedure on page 11.

WARNING

To reduce the risk of serious injury whenever you are instructed to relieve pressure, always follow the Pressure Relief Procedure on page 11.

With the bleeder type main air valve (1) turned off, remove the thumb screws (14) and the two guards (15) from the sides of the proportioner. The wet cups (18) should be filled to 1/3 full with Graco Throat Seal Liquid (TSL) or compatible solvent.

The packing nuts (19) are torqued at the factory and are ready for operation. If one becomes loose and there is leaking from the throat packings, relieve the pressure, then torque the nut to 136–149 N.m (100–110 ft-lb) using the supplied wrench (20). Do this whenever necessary. Do not over tighten the packing nut.

Bearings

Many of the bearing surfaces on the proportioner are permanently lubricated or are self lubricating. There are four main bearings (21) on the lever arm that must be lubricated on a regular interval. The lubrication interval is every six months in single shift operation. To lubricate the bearings, follow the pressure relief procedure on page 11.

WARNING

To reduce the risk of serious injury whenever you are instructed to relieve pressure, always follow the Pressure Relief Procedure on page 11.

With the bleeder type main air valve turned off, remove the twenty hex bolts (16) with a 13mm wrench or socket and then remove the four sheet metal covers (17) from the front and back of the proportioner.

The left rear cover may contain a sensor attached to a cable. Do not remove the sensor, but carefully set the cover to the side without straining or damaging the sensor or cable. The four main bearings (21) are now exposed. Use the adapter (205532) provided to grease all four bearings. One or two squirts (2-3 cc) will be sufficient.

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