Xylem Bell & Gossett Domestic CU Series User manual

INSTRUCTION MANUAL
DN0129
REVISION F

2
PRELIMINARY INSPECTION
Assure that there is no shipping damage.
Assure that nameplate ratings agree with job specifications and
actual conditions.
HANDLING
Use care in installing unit.
LOCATION
Place unit for easy access to all parts. Allow adequate space
for servicing. Check ambient conditions.
NOTICE / TEMPERATURE LIMITS
Motors are designed to operate in 104ºF (40°C) max. ambient.
Insulate or ventilate as required.
PIPING (General)
Pipe the unit per the Elementary Piping Diagram. Locate and
support piping so as not to load the pump discharge.
PIPING (Returns)
Gravity return lines from the system must be properly pitched
down to unit inlet. Returns must also be trapped to pre-
vent steam entry into the unit. An inlet basket strainer is
recommended.
PIPING (Vent)
Install a vent pipe to atmosphere. Pipe to be size of vent port
on unit. Do not restrict or reduce vent opening or exceed 20
inch vertical height unless an overflow connection is provided.
FLOAT SWITCHES AND MECHANICAL ALTERNATORS
The floats which operate these swithces are factory set but can
be field readjusted as required.
Adjustment is made by removing the float switch as an assem-
bly and readjusting the stop collars on the float rod.
Setting should utilize as much of the tank volume as practical.
Settings should avoid “short cycling”of the pump. See page 3
for detailed instructions.
ELECTRICAL WIRING & CONTROLS
Connect power wiring per NEC. Rechceck nameplate vs. spec-
ifications and conditions. All single phase motors have internal
thermal protection.
Three phase motors must use starters with properly sized over-
load relays. Overload relays furnished are designed for manual
reset.
AIR VENT
TO DRAIN UNION
CHECK VALVE GATE VALVE
STEAM COCK
DISCHARGE
CONDENSATE
RETURN LINE
UNDERGROUND
CONDENSATE
RETURN LINE
BASKET
STRAINER
(OPTIONAL)
UNION
TO DRAIN
IDPD33
AIR VENT
TO DRAIN
WATER LINE
OF BOILER
UNION
CHECK VALVE GATE VALVE
STEAM COCK WATER MAKE-UP
WITH 3 VALVE BYPASS
OPTIONAL
DISCHARGE TO BOILER
DETAIL AA
WATER
MAKE-UP
SUPPLY
(SEE DETAIL AA)
CONDENSATE
RETURN LINE
UNDERGROUND
CONDENSATE
RETURN LINE
BASKET
STRAINER
UNION
TO DRAIN
IDPD44
SERIES CU – CONDENSATE UNIT
DESCRIPTION
Series CU condensate units have one (simplex) or two (duplex)
pumps which are controlled by a float(s) switch or mechanical
alternator switch in the receiver.
These pumps return accumulated condensate to the boiler
feed system.
Series CMU boiler feed units have one (simplex) or two (duplex)
pumps which are controlled by boiler system controllers. Series
CMU receivers are sized to provide for accumulating system
surges of condensate. Water makeup valves are also included
to insure that water is always available to meet boiler demands.
Standard receivers are non-code epoxy coated steel.
SERIES CMU BOILER FEED UNIT
REPRESENTATIVE PIPING DIAGRAMS
WARNING: EXPLOSIBLE
Do not pressurize receiver. Isolate receiver during leak
test. Do not plug overflow. Do not restrict vent opening to
atmosphere. Open valves slowly. Failure to follow these
instructions could result in serious injury or death.
CAUTION: NOT A CHEMICAL PUMP
Inject boiler feed compounds from chemical feed tank
into boiler feed piping –never into condensate tank. Failure
to follow these instructions could result in injury or property
damage.
WARNING: HIGH VOLTAGE ELECTRICITY
Disconnect and lock out power before connecting or
servicing unit. Failure to follow these instructions could
result in serious injury or death.

3
FLOAT SWITCH ADJUSTMENT
The float positions are factory set. These positions should be
reset as necessary. Minor deviation is permissible to meet local
requirements. The settings must avoid “short cycling”of the
pumps.
The float switch and mechanical alternator each have an inter-
nal compensating spring to balance the weight of the float
guide rod. These springs are to have just enough tension or
compression on the float switch to counterbalance the guide
rod (but not the float).
PIPING DIAGRAMS VACUUM TIGHT
UNDERGROUND CONDENSATE &
BOILER FEED UNITS
Type CVU units are designed for use as a mechanical lift in a
vacuum heating system. They are also used to return conden-
sate under vacuum to a boiler feed tank. They have vacuum
tight displacer switch(es) for pump control.
Type CMVU units have water make-up valve and are actuated
by boiler controller. They are designed for use in a vacuum sys-
tem to discharge condensate directly to the boiler.
It is necessary to pipe the vent line to atmosphere using full
vent port size piping with check valves installed as shown on
diagrams. It is also recommended that the vent line be
“dripped”to drain to prevent an accumulation of condensate in
the vent pipe.
*MAKE SETTINGS
WITH ARM AT
HIGHEST POSITION
MECHANICAL
ALTERNATOR
FLOAT SWITCH
2DFS01
PIPING DIAGRAM FOR UNDERGROUND
CONDENSATE UNIT USED
IN A VACUUM SYSTEM
PIPING DIAGRAM FOR UNDERGROUND
BOILER FEED UNIT USED
IN A VACUUM SYSTEM
FLOAT SETTING CHART
Condensate Unit
Single Duplex Duplex 2 Float Switch Boiler
Primary Stand-By Feed
Unit (Mech. Alt.) Float Switch Float Switch Unit
Depth “A”“B”“A”“B”“A”“B”“A”“B”“A”“B”
36" 11" 22" 81/2" 21" 121/2" 22" 11" 22" 14" 22"
48" 11" 34" 81/2" 33" 121/2" 34" 11" 34" 26" 34"

4

5

6
PUMP SERVICE INSTRUCTIONS FOR UNDERGROUND CENTRIFUGAL PUMPS
Vertical mounting puts motor above floor dirt and water.
These instructions are for pump disassembly. The mechanical seal
can be replaced without complete pump disassembly as detailed
on the prior page.
1. Close inlet gate valve and operate pump momentarily to
remove as much liquid as possible from pump. Close dis-
charge line gate valve.
2. Shut-off and lock out power.
3. Make sure unit is cool enough that pump can be handled safely.
4. Loosen the discharge pipe. Assure that pressure is relieved per
caution note.
5. Disconnect motor leads, conduit and discharge pipe.
6. Remove coverplate and pump assembly.
7. Remove discharge connection and tubing.
8. Remove capscrews holding volute and lower bearing head.
9. To remove impeller from motor shaft proceed as follows:
a) Remove self locking capnut and washer or self locking cap-
screw and washer.
b) Hold end of shaft opposite pump with suitable tool and
back impeller off with a rectangular bar or other flat tool
inserted between the vanes of the impeller.
10. Remove motor from motor support (half of the flexible coupling
will come away with the motor) and set aside.
11. Remove remaining part of flexible coupling. Use puller.
12. Remove grease coverplate from bearing support.
13. Remove the snap-ring from above the bearing.
14. Remove the four capscrews that hold the bearing support.
15. Insert two screws 3/8x 16 at least 11/2" long, into the tapped
holes in the flange around the bottom of the bearing support,
remove the bearing support by turning both screws evenly, or
by alternating half-turns.
16. With the bearing support freed, remove the stationary part of
the seal, the slinger, and the bearing from the bearing support.
Remove the old gasket.
17. Remove bearing (note: bearing is shielded on lower side).
18. Remove rotating part of seal from shaft. Remove collar when
replacing shaft only.
19. Reassemble pump using new gaskets, reversing procedure
and following mechanical seal replacement steps described on
prior page.
20. When replacing lower bearing, remove lower carbon bearing
from lower bearing head and install new bearing.
Note: If lower bearing is made of bronze, then a complete new
lower bearing head assembly is required.
21. Reconnect pump bleed line and motor wiring.
22. Slowly open inlet gate valve. See warning.
23. Jog to check motor rotation. See caution.
CAUTION: PRESSURIZED SYSTEM
Operating system may contain very hot water under
pressure. Close inlet and open drains before servicing.
When servicing, loosen screws and move components to
assure pressure is relieved before removing screws. Keep
drains open during servicing. Failure to follow these instruc-
tions could result in injury or death.
CAUTION: HOT SURFACE
Surfaces are hot when system is in operation. Do not
touch hot receiver, let unit cool before servicing. Failure to
follow these instructions could result in serious injury or
death.
WARNING: HIGH VOLTAGE
Disconnect and lock out power before connecting
servicing unit. Failure to follow these instructions could
result in serious injury or death. CAUTION: DO NOT REVERSE
Reverse operation can cause extensive damage to
pumps. Jog the motor to test for direction of rotation. Failure
to follow these instructions could result in serious injury or
property damage.
CAUTION: DO NOT RUN DRY.
SEAL DAMAGE MAY OCCUR.
Inspect pump seal regularly for leaks Replace as required.
Failure to follow these instructions could result in serious
injury or death.
WARNING: EXPLOSIBLE
Do not pressurize receiver. Isolate receiver during leak
test. Do not plug overflow. Do not restrict vent opening to
atmosphere. Open valves slowly. Failure to follow these
instructions could result in serious injury or death.
COLLAR
FLOAT STOP
2DPU02
2DPU04
FLOAT ROD
FLOAT
COLLAR
FLOAT STOP
FLOAT ROD GUIDE
GASKET CASE
IMPELLER
BRONZE ENCLOSED
ORIFICE
ORIFICE
DRAIN PLUG
CASE RING BRASS
CASE
DISCHARGE ELBOW
LOWER BEARING
HEAD
PUMP SUPPORT
COLUMN. PILOTED
DISCHARGE PIPE
INTERMEDIATE
BEARING HOUSING
WHEN USED
INLET
DRAIN PLUG
CASE RING BRASS
CASE
INTERMEDIATE
BEARING OIL-LESS
WHEN USED
LOWER BEARING
OIL-LESS
DISCHARGE ELBOW
LOWER BEARING
HEAD
LOWER BEARING
OIL-LESS
PUMP SUPPORT
COLUMN. PILOTED
DISCHARGE PIPE
INLET
IMPELLER SHAFT
STAINLESS STEEL
SEAL LUBRICATING
ASSEMBLY (WATER)
"O" RING
DISCHARGE FLANGE
EXPANSION JOINT
GASKET
DISCHARGE FLANGE
DISCHARGE FLANGE
GASKET
MOTOR SUPPORT
MOTOR SUPPORT
MECHANICAL SEAL
THRUST BALL BEARING WITH
SINGLE SEAL AND PROVISION
FOR RELUBRICATION
FLEXIBLE COUPLING
CUSHION SPIDER
MOTOR
GREASE CUP
FLOAT SWITCH
AUTOMATIC
ALTERNATOR
DUPLEX UNITS ONLY
SWITCH BRACKET
COLLARS (2)
SWITCH DRIP
VAPOR SEALS (2)
PIPE NIPPLE
RETAINING RING SHAFT
BEARING COVER
BEARING HOUSING
AIR VENT
CONTROL BASE
GASKET
CONTROL BASE
COVER PLATE
GASKET
RECEIVER SLINGER
STOP COLLAR
MECHANICAL SEAL
RECEIVER EPOXY COATED STEEL
COLLAR
FLOAT STOP
FLOAT ROD
FLOAT
ORIFICE
COLLAR
FLOAT STOP
FLOAT ROD GUIDE
GASKET CASE
IMPELLER
BRONZE ENCLOSED
ORIFICE
KEYS (2)
SET SCREWS (2)

7
TROUBLESHOOTING PROCEDURES (ITEMS MARKED WITH * FOR CMU ONLY)
All units are thoroughly tested at the factory before shipment.
They should operate satisfactorily without further adjustment if
properly installed and providing they have not been damaged
by rough handling in transit. If system or unit performance is
not satisfactory, refer to the following check list.
PUMP WILL NOT START
1. The power supply has been interrupted, disconnect switch
is open or selector switch is improperly positioned.
2. Incorrect voltage for motor. Check voltage and wiring with
motor characteristics.
3. Incorrect starter coil for power supply.
4. The overload relays in the starter have tripped out and
must be reset. Ambient temperature may be too high.
5. Check pump controls or other controls for proper operation.
6. Wiring to control cabinet is incorrect or connections are
loose.
7. The strainer is dirty thus retarding flow. Clean periodically.
*8. Boiler is full or boiler control switch is defective.
*9. The low water cut-off float switch is open due to low water,
incorrect adjustment or failure.
PUMP RUNS CONTINUOUSLY
1. Pump is running backward. Rotation of three phase
motors may be corrected by interchanging any two of the
three wires. Rotation should be clockwise looking down on
motor.
2. Steam traps are blowing through causing condensate to
return at excessive temperatures. This may reduce the
capacity of pump below its rating, depending on the unit
and type of pump furnished. Traps should be repaired or
replaced.
*3. Pump discharge pressure is less than operating pressure
of the boiler.
4. The total required pressure at the pump discharge is
greater than the pressure for which the pump was
designed. Check the total pressure which includes atmo-
spheric pressure, the friction head and the static head.
5. A valve in the discharge line is closed or throttled too tightly.
Check valve is installed backwards.
6. The impeller eye is clogged.
7. Pump is too small for the system.
PUMP IS NOISY
1. The pump is working against a lower pressure than
designed for. While pump is discharging, adjust plug cock
in discharge line until pressure at pump approaches pump
rated pressure.
2. Excessive condensate temperature. Correct system condi-
tions. However, this applies to certain units only; others are
designed to handle boiling water.
3. Magnetic hum or bearing noise in motor. Consult motor
manufacturer’s authorized service station nearest unit
location.
4. Starter chatters. Trouble is caused by low line voltage, poor
connections, defective starter coil, or burned contacts.
5. Pump is running backward. Rotation of three phase
motors may be charged by interchanging any two of the
three wires.
THE SYSTEM IS NOISY
1. Banging in the steam mains is usually caused by “implod-
ing”in condensate lying in low points in lines. These
pockets can be eliminated by dripping low points, prop-
erly supporting the pipe, or by increasing the pitch of the
lines.
2. Improper dripping of the steam mains and risers; where
there is a rise in the steam main, or where it branches off
into a riser, a drip trap must be installed to the drain line.
3. The piping is too small to drain properly.
4. A defective trap is holding condensate in steam supply
line.
*5. Defective check valve permits steam to vent thru pump
into the boiler feed tank.
6. A priming boiler is discharging water with the steam.
Consult boiler manufacturer.
EXCESSIVE WATER OVERFLOW FROM UNIT
1. Receiver sized too small to accommodate system surges.
*2. Water make-up valve open or float switch set too high.
*3. Water make-up valve leaks.

Xylem Inc.
8200 N. Austin Avenue
Morton Grove, Illinois 60053
Phone: [phone]
Fax: [phone]
www.xylem.com/bellgossett
Bell & Gossett is a trademark of Xylem Inc. or one of its subsidiaries.
© 2019 Xylem Inc. DN0129F October 2019