General Precautions; Standard Parts - Johnson Pump MDR Series Instruction Manual

1.6 General precautions

• Do not run dry. If the pump is run without liquid, friction heat will be generated inside
the pump which will melt the impeller onto the ceramic shaft and also possibly cause
damage to other parts.
• Do not use the pump for other liquids than quoted for without consulting your
SPX Process Equipment distributor.
• Do not run against closed valve. The pump will be damaged if it is run more than 3
minutes against closed valve.
• Do not run reverse. The impeller must rotate in clockwise direction when viewed from
the motor end (see rotation arrrow on the pump body).
• Do not run with cavitation or air entrainment.
• Do not run with fluid containing solid or abrasive particles without consulting your
local distributor.
• Do not expose the pump to thermal chocks.
• Check the impeller bearing, shaft and wear plates regularly for wear (see section 4.4).
• Do not cause chock pressure.

1.7 Standard parts

6
11
1. Pump body
2. Wear plate
3. Bearing
8
2 5 3
10
4. Impeller 7. Magnet housing
5. Ceramic 8. Reinforcement
shaft (not available for MDR45)
6. O-ring 9. Drive magnet
4 3 2
9 8 7
10. Flange
11. Motor
MDR/EN (0909) 1.0
1