Zoeller 7020 Operating instructions

SECTION: Z4.10.345
ZM3208
1119
Supersedes
New
NOTICE TO INSTALLER: Instructions must remain with installation.
Since 1939 the name Zoeller®has represented the standard for
submersible dewatering and sewage pumps. The same high quality
workmanship and easy maintenance design has been incorporated
into this line of heavy-duty submersible grinder pumps.
This manual incorporates the parts list and repair instructions into
one document to aid in the ownership of a Zoeller®submersible grinder
wastewaterproduct.Pleasereadandreviewthismanualbeforerepairing
REPAIR MANUAL
7020 & 7021 PROGRESSING CAVITY GRINDER PUMPS
Table of Contents
Safety Instructions .................................................................................... 1
Replacement Parts Breakdown ..........................................................2-3
Disassembly Procedures.......................................................................... 4
Assembly Procedures............................................................................5-6
Pump Wiring Diagrams............................................................................. 7
Service Checklist....................................................................................... 8
Safety Instructions
TO AVOID SERIOUS OR FATAL PERSONAL INJURY OR MAJOR
PROPERTY DAMAGE, READ AND FOLLOW ALL SAFETY
INSTRUCTIONS IN THIS MANUAL AND ON THE PUMP.
THIS MANUAL IS INTENDED TO ASSIST IN THE INSTALLATION AND
OPERATION OF THIS UNIT AND MUST BE KEPT WITH THE PUMP.
This is a SAFETY ALERT SYMBOL.
When you see this symbol on the pump or in the
manual, look for one of the following signal words
and be alert to the potential for personal injury or
property damage.
Warns of hazards that WILL cause serious personal
injury, death or major property damage.
Warns of hazards that CAN cause serious personal
injury, death or major property damage.
Warns of hazards that CAN cause personal injury or
property damage.
INDICATES SPECIAL INSTRUCTIONS WHICH ARE
VERY IMPORTANT AND MUST BE FOLLOWED.
THOROUGHLYREVIEW ALLINSTRUCTIONS ANDWARNINGS PRIOR
TO PERFORMING ANY WORK ON THIS PUMP.
MAINTAIN ALL SAFETY DECALS.
CAUTION
Short Term Storage
PLEASE FURNISH THE FOLLOWING INFORMATION:
• Model Number
• Part Number of Pump
• System Voltage
• ReplacementReferencePart Number andDescription. (refer topages
2 - 3)
To Order Replacement Parts
the product. Follow the steps and procedures listed on ZM1074 for a
proper start-up upon installation. Many items contained within, when
followed correctly, will not only ensure a long and problem-free life for
the pump, but also save time and money during installation. Reference
ZM2607 for owner’s manual on 7020 and 7021 Series Pumps. Should
further assistance be necessary please call our Product Support
Department at 1-800-928-PUMP (7867).
Storage of six months or less will not damage the submersible pump.
However, to ensure the best possible protection, the following is
advised:
• Store pump inside whenever possible or cover with some type of
protective covering.
• Tape or seal in plastic bag the terminal ends of wire leads.
• Spray coat unpainted surfaces with rust-inhibiting oil.
• See ZM2607 - Owner’s Manual before start-up.
MAIL TO: P.O. BOX 16347 • Louisville, KY 40256-0347
SHIP TO: 3649 Cane Run Road • Louisville, KY 40211-1961
[phone] • 1 (800) 928-PUMP • FAX [phone]
Visit our website:
zoellerengineered.com
Product information presented
here reects conditions at time
of publication. Consult factory
regarding discrepancies or
inconsistencies.
© Copyright 2019 Zoeller®Co. All rights reserved.

2
© Copyright 2019 Zoeller®Co. All rights reserved.
8
11
10
9
35
14
12
13
16
15
7
6
33
5
18
19
20
21
36
22
23
24
34
34
32
43
34
32
43
2
APPLICABLE CORD, SWITCH,
SEALS AND GROUND SCREW
1
"E" MODEL "E" MODEL MAN. RUN
17
42
40 39
31 30
29
28 27
43
44
37
38
41
26
25
34
32
43
"RE" MODEL
46
45
34
34
32
43
"Z" MODEL
"RWD" MODEL
32
43
47
48
49
34
SK2653

3
© Copyright 2019 Zoeller®Co. All rights reserved.
• Items included in Rebuild Kit.
** Quantity dependent on model of pump.
PARTS LIST FOR MODELS “7020, 7021”
REF
NO. DESCRIPTION QTY PART NUMBER NOTES
1 • HANDLE 1 217069
2 COVER & CORD 1 For replacement parts refer to ZM2637 for Model 7020 and ZM2638 for Model 7021
3 CORD, TERM & SEAL ASM 1 For replacement parts refer to ZM2637 for Model 7020 and ZM2638 for Model 7021
4 • SEAL, CORD-ASM & STR RLF 1 For replacement parts refer to ZM2637 for Model 7020 and ZM2638 for Model 7021
5 COVER-MACH. 1 For replacement parts refer to ZM2637 for Model 7020 and ZM2638 for Model 7021
6 • GASKET, CASE/COVER, VITON 1 012649
7 • WIRE PKG. 1 For replacement parts refer to ZM2637 for Model 7020 and ZM2638 for Model 7021
8 CAPACITOR & CLAMP ASM 1 For replacement parts refer to ZM2637 for Model 7020 and ZM2638 for Model 7021
9 • PLUG, TEST 2 015023
10 • SEAL, THRU WALL TERM 3 003402
11 HOUSING, MTR-& STR 1 For replacement parts refer to ZM2637 for Model 7020 and ZM2638 for Model 7021
12 • SPRING, BEARING PRELOAD 1 017192
13 • BEARING, UPPER 6201 1 006703
14 ROTOR & BRG ASM 1 For replacement parts refer to ZM2637 for Model 7020 and ZM2638 for Model 7021
15 • KEY 1 017893
16 • BEARING, LOWER 6204 1 012544
17 • SEAL, MTR HSG, VITON 1 012648
18 • OIL, DIELECTRIC-(57 OZ CAN) 1 009051
19 ADAPTER-MACH. 1 017891
20 • SEAL, SHAFT, SILICON CARBIDE/CARBON 1 155723
21 • WASHER, SEAL LOCATING & SNAP RING 1 018913
22 ROTOR, PUMP-HYDRAULIC & PIN 1 018915
23 • PIN 1 018892
24 • SEAL, PUMP HOUSING, VITON 1 151078
25 HOUSING, PUMP-MACH. & PRESS. RLF VALVE 1 Model 7020 PN 019550 / Model 7021 PN 019551
26 LEG, WIREFORM 1 151920
27 VALVE, PRESSURE RELIEF 1 Model 7020 PN 018432 / Model 7021 PN 018433
28 STATOR, HYDRAULIC 1 151617
29 • INSERT, STATOR SS 6 018369
30 CUTTER & DISC ASM 1 For replacement parts refer to ZM2637 for Model 7020 and ZM2638 for Model 7021
31 SHIM SET 1 012632
32 CLAMP, STRAIN RELIEF 1 For replacement parts refer to ZM2637 for Model 7020 and ZM2638 for Model 7021
33 • SCREW, .25-20 X .75 HHM-SS 4 001916
34 • SCREW, #6-32 X .25 RHM SL TC STLGR ** 001877
35 • SCREW, .25-20 X 1 HHM-SS 4 007790
36 • SCREW, .313-18 X 2 HH CAP FULL THREAD/SS 4 018186
37 • WASHER, FLAT-SS .313 4 015914
38 • NUT, .313-18 H–SS 4 001813
39 • WASHER, RETAINING SS 1 008533
40 • SCREW, .25-20 X .75 HH SS (NYLOCK) 1 009545
41 • WASHER, FLAT-SS .25 ** For replacement parts refer to ZM2637 for Model 7020 and ZM2638 for Model 7021
42 • SCREW, .25-20 X .875 (1.125 LENGTH FOR PLATE W/O
RECESS) 6For replacement parts refer to ZM2637 for Model 7020 and ZM2638 for Model 7021
43 DISC, CUTTER 1 For replacement parts refer to ZM2637 for Model 7020 and ZM2638 for Model 7021
44 CUTTER/SHIM/ASM 1 For replacement parts refer to ZM2637 for Model 7020 and ZM2638 for Model 7021
45 RELAY 1RE & RWD models only, for replacement parts refer to ZM2637 for Model 7020 and
ZM2638 for Model 7021
46 INSULATION - INSULATOR ** RE & RWD models only, for replacement parts refer to ZM2637 for Model 7020 and
ZM2638 for Model 7021
47 SWITCH, FLTS - TERM & SEAL ** RWD models only, PN 153383
48 • SEAL, CORD - FLT SWITCH ** RWD models only, PN 094043
49 • CONNECTOR WIRENUT ** RWD models only, PN 003753
¤REBUILD KIT For replacement parts refer to ZM2637 for Model 7020 and ZM2638 for Model 7021

4
© Copyright 2019 Zoeller®Co. All rights reserved.
Disassembly Procedures
DISASSEMBLY PROCEDURES
A. Before you begin...
1. Shut off pump.
2. Disconnect power source.
3. Remove pump from system.
B. When removing cutter (44)...
1. Complete Section A.
2. Immobilize the cutter (44) by placing a brass or aluminum rod in one
of the holes in the cutter plate (43). Turn the cutter until it is against
the rod in the correct direction to remove the cutter screw (40).
NOTE: It may be necessary to heat the hex head screw with a propane
torch to soften the thread compound.
CAUTION
Do not chip or nick the cutter while using the rod to
immobilize the cutter.
3. Using a socket remove the cutter screw (40) and washer (39)
4. Remove the cutter (44).
5. Remove the cutter shims (31).
NOTE: Count the number of shims removed so the same number and
sizes can be installed upon reassembly.
C. When removing cutter plate (43)
1. Complete section A and B.
2. Remove the six screws (42) and washers (41).
3. Remove the cutter plate (43).
D. When removing hydraulic rotor & stator
1. Complete Sections A and B.
2. Remove four nuts (38) and washers (37) from pump stand (26)
3. Remove pump stand (26)
4. Remove four screws (36) from pump housing
5. Rock pump housing back and forth to work stator (28) from rotor
(22)
6. Push pin (23) out of rotor with pin removal tool
7. Remove hydraulic rotor (22) from electric rotor (14)
8. Complete C. to remove cutter plate (43) and hydraulic stator (28)
E. When removing shaft seal (20)...
1. Complete Sections A, B and D.
Pump should be at room temperature. Seal and motor
housing may be pressurized. Care should be used in removing oil
plugs (9) so that oil is not sprayed.
CAUTION
Do not touch sealing face of the rotating section or the
stationary section of the rotary seal (20) when removing or installing
seal. Seal replacement should be done in shop atmosphere if
possible.
2. Slowly remove the oil plug (9) from the side of the motor housing
(11) (see warning above).
3. Turn the pump on it’s side to drain the motor chamber oil.
4. Remove the seal snap ring (21) from the shaft and washer.
5. Usingabearingpulleror othersuitabletools,pull therotatingsection
of the rotary seal (20) from the rotor shaft. If needed, carefully pry
rotating section loose and pull off by hand.
6. The stationary seal can be pried with a screw driver. Be careful
not to chip as chips may fall into motor.
F. When removing the cover and power cord assembly (2)...
1. Complete section A.
2. Remove the four screws (33) that secure the cover (2) to the motor
housing (11).
3. Remove the cover and cord (2) assembly from motor housing.
NOTE: If cover does not immediately come loose, a gentle tap with dead
blow hammer or rubber mallet may be necessary.
4. Removethepower lead connectionsfrom the throughwallterminals
(10) in motor housing (11). Set cover and cord assembly aside.
5. Remove seal gasket (6) from the cover and inspect for damage.
6. To remove cord assembly, loosen and remove gland nut (4).
7. Remove the ground screw and disconnect the ground wire from
the inside of the cover.
8. Cut away strain relief (32).
9. Pulling on the power cord, remove from the cover. The entire length
of the power cord will be pulled through the cover.
NOTE: It may take some wiggling and prying to loosen this assembly,
because the rubber seal (3) will have taken a set.
10. Inspect the cord seal (4) for damage.
G. When removing motor rotor (14)...
1. Complete sections A, B, D and E. Section C and F may or may not
be completed rst.
2. Remove four screws (35) between motor housing (11) and adapter
(19).
SHIM TO
.007 TO .012
RUN CLEARANCE
SK3237

5
© Copyright 2019 Zoeller®Co. All rights reserved.
Assembly Procedures
assembly(3). Theassembly consists ofthepower cord, thewireterminals,
and the cord seal assembly.
1. Unroll the cord of the cord terminal and seal assembly (3)
2. Install gasket (6) on top of motor housing (11).
3. Suspend the cord and cover assembly over the motor housing and
make wiring connections per the proper wiring diagram (page 7).
4. Tuck the wires in the cover assembly as installing the cover into place.
5. Secure the cover (5) to the motor housing (11) with four screws (33).
6. Torque screws to 63-67 in-lbs.
NOTE: Align the straight (non circular) surface of cover with the straight
surface of motor housing.
D. Installation of rotary seals and seal retainer...
CAUTION
Make sure all seal faces remain free of dirt particles.
Apply a light coat of oil to seal faces before installing.
1. Refer to rotary seal component placement diagram for relative
positioning of seal parts.
2. Apply Loctite # 609 to OD of SS seal cup, and using a nonmetallic
sleeve, press the seat into position in the adapter.
3. Apply oil (18) to the shaft and to the inside diameter of the rotating
section of rotary seal (20). Push the rotating section onto the shaft in
a continuous motion until the seal faces meet.
4. Install washer and retaining ring (21) in the groove of the rotor shaft.
ROTARY SEAL COMPONENT PLACEMENT
DIAGRAM
E. Installing the hydraulic rotor...
1. Slide hydraulic rotor (22) onto electric rotor shaft (14)
2. Align holes in rotor to press in pin (23)
3. Use pin tool (156797) with installation driver to start pin. Drive the pin
(23) ush with hydraulic rotor.
SNAP RING
WASHER
ROTATING SECTION
STATIONARY SECTION
SPRING
SK3269
3. Lift the motor housing (11) off the adapter (19). Be careful to lift the
motor housing straight up, so as not to damage the stator windings
or bearings.
4. Remove bearing pre-load washer (12) from motor housing (11) and
inspect.
5. Remove rotor assembly (14) from adapter (19).
6. Using a bearing puller, against the inner race, remove the lower
bearing (16) and upper bearing (13) from the shaft. Replace the
bearings if needed.
NOTE: Bearings should be cleaned with volatile mineral spirits and
relubricated with proper lubricants immediately after cleaning. Never
drybearingswithcompressedair,andneverspinun-lubricatedbearings.
H. Motor Stator...
NOTE: The motor housing and stator assembly removed in Section G
number 3, is a factory assembled unit and must be replaced as such:
it consists of the motor housing, the glued in stator, and the through
wall electrical terminals for the power wires.
ASSEMBLY PROCEDURES
Pumps are reassembled in reverse order of disassembly. The following
suggestions are offered.
NOTE:Whilethepump is dismantled,allgaskets,seal rings andretaining
rings should be checked for wear and deterioration. Replace all worn
items. Ensure that all parts are thoroughly cleaned before assembly.
A. Assembly of rotor (14)...
1. Inspect rotor to see that the snap ring is in place and snapped in
thegroove. Thissnap ring servesas alocator forthe lowerbearings.
NOTE: Before installing the bearings, wipe the bearing seats on the
shaft clean and coat the seats with oil to prevent galling of the shaft
as the bearings are pressed onto the shaft. A properly sized pressing
sleeve should be used to install bearings, with pressure being applied
to only the inner bearing race.
2. Install the lower ball bearing (16) and the upper ball bearing (13)
on the rotor shaft (14).
3. Set the adapter (19) on blocks to allow the rotor shaft to clear the
work surface when installed.
4. Install the rotor/bearings assembly into the adapter housing (19).
Make sure the lower bearing is seated in the bearing pocket.
B. Installing the motor housing/stator (11)...
NOTE: The motor housing/stator assembly is furnished from the factory
as a glued-in unit. The assembly will include the motor housing, the
stator prewired to installed through wall terminals (10).
1. Lightly oil and position the seal ring (17) around the pilot shoulder
of the adapter (19).
2. Install the pre-load washer (12) in the upper bearing pocket of the
housing/stator unit (11). The pre-load washer should be stretched
a little to allow it to remain in the pocket when turned upside down.
3. With the rotor/adapter assembly in the vertical position suspend
the motor housing/stator unit over it. Slowly lower the unit aligning
the rotor and stator opening.
4. Secure the motor housing/stator (11) to the adapter (19) with four
screws (35)
5. Torque screws to 63-67 in/lbs.
C. Installing cord and cover assembly...
NOTE: The cord will come from the factory as a cord terminal and seal

6
© Copyright 2019 Zoeller®Co. All rights reserved.
Leak Test
(Before oiling pump) Perform a leak test on the pump seals
by installing a regulated air supply into the holes (1/8" NPT
access). The motor chamber, and cover chamber must be
checked. The pressure of the air supply should be set at
approximately 9 PSI. Submerge the pump in clear water
watching for small air bubbles around square ring seals, rotary
seal, cord connection, and oil fill plugs.
NOTE: Make certain that the pump is placed in the water so that no
areas are present that would trap air (such as the cavity around the
lower rotary seal), not allowing the bubbles to rise to the water surface.
If it is not possible to leak test the pump using the submersion method, a
regulated air supply with a (0-15 PSI) air gage can be installed in the ll holes.
The pump to be pressurized and held at 9 PSI. After removing the air supply,
the pressure should not drop more than ½ PSI in a 24 hour period.
H. Oiling and final assembly.
Refiner Product Name
Arco Duro 22 or 32
Exxon Teresstic 22 or 32 or acceptable equal
Chevron Clarity Hydraulic Aw ISO22 or ISO32
1. While pump is on its side pour (18) in motor housing.
Do not over ll.
2. Clean pipe plugs and reapply pipe dope or teon tape. Install pipe
plugs (9) in motor housing (11)
3.
CAUTION
Do not operate an unsubmerged progressing
cavity pump. Dry pump operation may damage the hydraulic stator
due to lack of lubrication. Do not run dry.
F.Installing hydraulic stator and pump housing...
1. Place hydraulic stator (28) in pump housing (25)
2. Make sure all 6 stator inserts (29) are in place
3. Place cutter plate (43) on stator
4. Install 6 screws (42) and washers (41)
5. Torque screws to 63-67 in-lbs
6. Cover rotor (22) in red all pupose grease
7. Place square ring (24) in groove, use all purpose grease to hold
in place if necessary.
8. Slide assembled pump housing (25) stator (28) unit over rotor,
rocking back and forth until seated against adapter (19)
9. Install four screws (36). Torque to 125-130 in-lbs
G. Installing the cutter (30)...
1. Install the proper amount of shims (31) on the shaft to obtain the
proper running clearance between the cutter plate (43) and cutter
(44).
2. Install the cutter (44) onto the shaft.
3. Install the screw (40), and at washer (39) using thread-locking
compound and torquing to 71-75 in/lbs.
Note: Immobilize the cutter by placing a aluminum or brass rod in
one of the holes in the cutter plate.
CAUTION
Do not chip or nick the cutter while using the
rod to immobilize the cutter.
4. Withthe pump in the vertical position to remove end play, measure
the running clearance between cutter (44) and cutter plate (43)
using a feeler gauge. Repeat 1 thru 3 until .007" to .012" clearance
is obtained. (See cutter clearance diagram on page 4).
Assembly Procedures (continued)

7
© Copyright 2019 Zoeller®Co. All rights reserved.
Wiring Diagrams
"RWD 7020 & RWD 7021"
WITH MANUAL RUN
002397
"E 7020 & E 7021"
RUN
O.L.
MOTOR
(3)
BLUE RED
WHITE
BLACK
GREEN
L1 L2
START
(1) (2)
YELLOW
BLUE RED
CAPACITOR
(WHITE) (BLACK)
(BROWN)
RUN
O.L.
MOTOR
(3)
BLUE RED
STA RT
(1) (2)
YELLOW
(WHITE) (BLACK)
(BROWN)
SWITCH
PUMP
SWITCH
ALARM
R
4
60
1
R
2
64
5
GE RELAY
BLUE RED
CAPACITOR
WHITE
BLACK
RED
RELAY
YELLOW
BLUE
GREEN
ORANGE
BLUE
WHITE
BLACK
BLACK
WHITE
BLUE
RED
BLACK
WHITE
1)
NOTES:
INSULATORS REQUIRED ON GE RELAY TERMINALS 2 & 5;
OMRON RELAYTERMINALS 1 & 4.
153875
"RE 7020 & RE 7021" WITH
MANUAL RUN
RUN
O.L.
MOTOR
(3)
BLUE RED
GREEN
START
(1) (2)
YELLOW
BLUE RED
CAPACITOR
(WHITE) (BLACK)
WHITE
BLACK
RED
YELLOW
BLUE
ORANGE
R
RELAY
4
60
1
R
2
64
5
GE RELAY
(BROWN)
1)
NOTES:
INSULATORS REQUIRED ON GE RELAY TERMINALS 2 & 5;
OMRON RELAY TERMINALS 1 & 4.
152554
RUN
O.L.
MOTOR
(3)
BLUE RED
START
(1) (2)
YELLOW
(WHITE) (BLACK)
(BROWN)
SWITCH
PUMP
SWITCH
ALARM
R
4
60
1
R
2
64
5
GE RELAY
BLUE RED
CAPACITOR
WHITE
BLACK
RELAY
YELLOW
BLUE
GREEN
RED
ORANGE
WHITE
BLACK
BLACK
WHITE
BLUE
RED
BLACK
WHITE
1)
NOTES:
INSULATORS REQUIRED ON GE RELAYTERMINALS 2 & 5;
OMRON RELAY TERMINALS 1 & 4.
"RWD 7020 & RWD 7021"
WITHOUT MANUAL RUN
153381

8
© Copyright 2019 Zoeller®Co. All rights reserved.
Do not operate an unsubmerged progressing cavity pump. Dry pump operation may damage the hydraulic stator due to lack
of lubrication. Do not run dry.
ELECTRICAL PRECAUTIONS Before servicing a pump, always shut off the main power breaker to the panel and then disconnect the pump
- making sure you are wearing insulated protective sole shoes and are not standing in water. Under ooded conditions, contact your
local electric company or a qualied licensed electrician for disconnecting electrical service prior to pump removal.
Submersible pumps contain oils which become pressurized and hot under operating conditions - allow 2-1/2 hours after disconnecting before at-
tempting service.
CONDITION
A. Pump will not start or run.
COMMON CAUSES
B. Motor overheats and trips overload or blows fuse.
- Incorrect voltage
- Unbalanced power source
- Negative or low head
- Excessive water temperature
- Hydraulic stator and rotor or seal mechanically bound
- Defective capacitor or relay
- Motor shorted
C. Pumps starts and stops too often.
- Check valve stuck open
- Level controls out of adjustment
- Temperature sensor tripping
- Thermal overload switch out of adjustment or defective
- Pit too small
D. Pump will not shut off.
- Debris under oat switch
- Float travel obstructed
- Defective or damaged oat switch
- Magnetic starter contacts shorted
E. Pump operates but delivers little or no water.
- Closed valve or curb stop
- Check for plugged pump housing, discharge
pipe or sticking check valve
- Vent hole clogged or not drilled
- Discharge head exceeds pumps capacity
- Low or incorrect voltage
- Damaged hydraulic stator or rotor
- Defective capacitor
F. Drop in head and/or capacity after a period or use.
- Increased pipe friction
- Clogged line or check valve
- Abrasive material & chemical,
deteriorated hydraulic rotor or stator
If the above check list does not uncover the problem, consult the factory - Do not attempt to service or otherwise disassemble pump.
Steps Check Voltage At If No Voltage If Voltage
No. 1 Line terminals in pump Check disconnect switch, line Proceed to No. 2
control panel fuse, and/or circuit breakers
L1- L2in power supply circuit.
No. 2 Pump motor terminals in Check for control circuit Check starting relay
pump control panel voltage. Check out magnetic and capacitor (1 phase units).
T1- T2starter contacts, thermal Check pump for ground
overloads, and oat switches and bound cutter
Service Checklist & Trouble Shooting
CAUTION