Grundfos LF User Manual

13
English (US)
8.3.2 Disassembling the pump
1. Remove the pump housing screws (8B).
2. Remove the back pull-out bearing frame (20Y) from the pump
housing (1A).
3. Remove the impeller screw (8A).
If necessary, use a strap wrench around the impeller or shaft
to prevent rotation.
4. Use an appropriately sized puller aligned behind the impeller
vanes to remove the impeller (3A) from the shaft (6A).
5. Remove the impeller key (12A).
6. Remove the back plate screws (8D). Remove the back plate
(2K) and the seal housing (26P).
7. Place the seal housing on a flat surface and press out the
shaft seal (14A).
8. If the shaft sleeve (5A) requires replacement, heat it evenly to
approximately 350 °F (176 °C) to loosen the thread-locking
fluid. Twist the sleeve off the shaft (6A).
8.3.3 Disassembling the bearing frame (LF)
1. Remove the slinger (13G).
2. Remove the lip seal(s) (14S), if any.
3. Remove the bearing housing locking ring (61K).
4. Press or tap on the pump end of the bearing-shaft assembly
until one bearing is out.
5. When one bearing is out, remove the second locking ring
(61F), then remove the complete bearing-shaft assembly from
bearing housing.
6. Remove the shaft locking ring (61C) and press off the
bearings.
7. Press new bearings on to the shaft; remember to press only
on the inner race of the bearings while pressing them on.
8. Assemble the bearing frame in the reverse procedure used for
disassembling.
9. Observe the following when reassembling the bearing frame:
– Replace the lip seals (14S) if they are worn or damaged.
– Replace the bearings (18A) and (18B) if they are loose,
rough or noisy when rotated.
– Check the shaft (6A) for shaft runout at the shaft sleeve (5A)
area. Maximum permissible runout is 0.002 in. (0.05 mm)
total indicator runout.
8.4 Replacing the shaft seal (LCS pumps)
1. Complete the preparations listed in section 8.3 Disassembling
the pump.
2. Remove the coupling guard screws (8E).
3. Remove the coupling guard (34F).
4. Remove the nut (35E) and the bolt (8E) that hold the coupling
halves together.
5. Pry apart the coupling halves (23D), remove the coupling key
(12B).
6. Unscrew the tubing connector from the pipe tee of the air vent
assembly. Thread sealing compound was applied to the
threads during factory assembly, and the resulting bond may
retard but will not prevent manual disassembling.
7. Remove the seal housing cap screws and slide the seal
housing (2N) up the shaft to remove it.
8. Remove the shaft seal manually from the shaft (6A). Apply
water-soluble lubricant to the shaft, if necessary, to ease the
removal of the shaft seal (14A). Pull the shaft seal manually
from the shaft, using a slight twisting motion (as necessary) to
loosen the bellows from the shaft.
9. Remove and discard the shaft seal spring and the shaft seal
retainer.
10. Remove and discard the shaft seal seat from the seal housing
(2N) and thoroughly clean the inside cavity of the seal
housing.
11. The interior surface of the bellows on a new shaft seal is
coated with a bonding agent that adheres to the motor shaft.
When the old shaft seal is removed, the bonding agent no
longer exists and the bellows may crack or split during
removal. We always recommend that you install a new
mechanical shaft seal if it becomes necessary to remove the
existing shaft seal from the shaft.
12. Clean and lubricate the shaft (6A) with a water-soluble
lubricant and make sure no sharp edges can cut or scratch
the bellows of the new shaft seal.
13. Press the new shaft seal seat firmly into the seal housing.
Avoid direct contact between the seal face and metallic or
abrasive objects, and wipe the seal face clean after
installation to ensure an abrasive-free sealing surface.
14. Slide the new shaft seal onto the shaft by applying even
pressure to the shaft seal.
15. Install the shaft seal housing (2N) on the shaft.
16. See the reassembly instructions in section 8.6 Reassembling
the pump.
WARNING
Moving machine parts
Death or serious personal injury.
- Do not insert a screwdriver between the impeller
vanes to prevent rotation.
Mark or measure the original position of the pump
coupling on the motor side.
LC_LCV_LF_LCS_1 language_US Eng.book Page 13 Thursday, August 24, 2017 4:08 PM

Grundfos LF Specifications

General

Brand	Grundfos
Model	LF
Category	Water Pump
Language	English