Bell & Gossett DN0412C HS Vented Boiler Feed Units Series HSM - Manual (Page 6)

Close coupled centrifugal pumps are designed for years of trouble
free service. Units have mechanical shaft seals.
1. Close inlet gate valve and operate pump momentarily to remove
as much liquid as possible from pump. Close discharge line gate
valve.
2. Shut-off and lock out power.
3. Make sure unit is cool enough that pump can be handled safely.
Open drain to remove remaining liquid.
4. Carefully remove pump drain plug and bleed line. Wait for com-
plete drainage.
5. Loosen the motor bracket to pump volute capscrews. Assure that
the pressure is relieved per caution note.
6. Complete the removal of the hardware. Remove pump/motor
assembly and place on work bench.
7. Remove self locking stainless steel capscrews and stainless steel
washer (or self locking brass cap nut and washer) that secure the
impeller in place.
8. To remove impeller from motor shaft proceed as follows:
(1) Keyed Shafts. Remove impeller with gear puller or other
means which will not damage impeller or bend motor shaft.
(2) Threaded Shafts. Hold end of motor shaft opposite pump with
large screwdriver or other suitable tool and back impeller off
with a rectangular bar or other flat tool inserted between the
vanes of the impeller.
9. Remove rotating part of seal from shaft, being careful not break
carbon face.
10. Remove capscrews holding motor bracket to motor and remove
bracket.
11. Remove stationary part of seal assembly, being careful not to chip
or break ceramic seal.
12. To install seal proceed as follows:
(1) Clean recess in bracket thoroughly. Coat recess and “rubber”
portion of seat with soap solution. Press seat into recess firmly
by hand making certain both parts bottom evenly. If seal can-
not be bottomed with fingers place cardboard shipping disc
on ceramic and force into place with flat tool.
(2) Carefully place bracket in position on motor shaft without
displacing ceramic seat and secure bracket to motor with
capscrews.
(3) Place motor vertically with pump end up. Do not attempt
assembly of seal and impeller with shaft horizontal.
(4) The “carbon” of rotating part of seal should not be loose. If it
is, hold in place with grease, Using clean, lint free cloth, wipe
mating surfaces perfectly clean. Soap shaft and push seal
onto shaft so that carbon will contact ceramic seal. If spacer is
required, use grease to cause spacer to adhere to bottom of
seal after seal has been put on shaft, Be sure spacer is on
larger diameter of shaft so that will not catch between shoul-
der and impeller.
13. Replace impeller on shaft. Replace stainless steel washer and
secure impeller with capscrew or cap nut.
14. Place new gasket on pump volute and reassemble motor and
pump subassembly on pump volute.
15. Reconnect pump bleed line and motor wiring.
16. Close drain and slowly open inlet valves. See warning.
17. Jog to check motor rotation. See caution.
18. Observe operation thru several cycles.
6
PUMP SER VICE INSTRUCTIONS FOR CENTRIFUGAL PUMPS (EXCEPT ‘B’ OR 609)
Vertical mounting puts motor above floor direct and water
CAUTION: PRESSURIZED SYSTEM
Operating system may contain very hot water. 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 fol -
low these instructions 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.
WATER
SLINGER
VIEW OF
THREADED
IMPELLER
WEAR RING
IMPELLER
2DPF03
VOLUTE
MOTOR BRACKET
MECHANICAL
SEAL
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: 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 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 injury or property
damage.