Pd pump Systems neslab p/N 000878 Rev. 08/15/96 Service Manual

motor will restart without warning when the thermal protec-
tor resets.
The thermal protector has a wide hysteresis (dead band), and the
motor must cool down almost to ambient before reset. This may
take considerable time due to the mass of the motor.
* One exception: Certain blue IMOFA-brand motors used in CFT units for
export to Europe have no internal thermal protector, but rather an external
circuit breaker mounted in the control box.

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Pump Replacement
Tools required:
Bucket
Nut driver
5/16" Wrench
Adjustable Bench Vise
Torque-type screwdriver, capable of 30 in/lb (170 cm/kg)
Torque-type wrench, 5/16", capable of 50 in/lb (280 cm/kg)
1. Disconnect unit from line voltage.
2. Drain the fluid from the system.
3. Loosen the hose clamp on each of the pump fittings using a
5/16" nut driver as soon as practical. Hose removal will be
much easier if the hose is allowed to relax for 10-15 minutes
after each clamp is loosened.
4. Loosen the V-band clamp and slide it up against the motor.
5. Pull the hoses off the hose fittings.
6. Remove the pump from the unit with the fittings intact.
7. Place the pump in a vise and remove the fittings from the
pump. They can generally be unscrewed without
desoldering. Don’t squeeze the round part of the pump in
the vise! The vise should hold the pump by the square boss
area just below the fittings.
8. Install the fittings in the new pump using Teflon® tape as a
sealant. Support the pump body in a vise or use a backup
wrench.
9. If soldering must be done on the fittings, do so before
installing them in the pump. Solder balls dropping into the
pump will destroy the vanes. If soldering must be done to
the fittings while on the pump, orient the pump so the
openings face downwards. Always use a soft solder: either
50/50 or 95/5 is acceptable.
10. Check the lubrication cup on the motor shaft. Refer to
COUPLING LUBRICATION for details.

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11. Check that the slot in the motor shaft is sharply rectangular,
without undue wear. The motor should also be replaced if its
slot is worn.
12. Be aware the coupling is not symmetrical! The wide end fits
in the motor and the narrow end fits in the pump.
13. Add some circulating fluid into the pump inlet fitting now to
assist in priming later.
14. Ensure mating flanges of both pump and motor are clean
and free of burrs that may have occured during handling.
File any burrs smooth. Remove and discard the foam
shipping strip from the coupling if it is present.
15. Attach pump to motor, guiding coupling into place.
16. Observe that flanges mate squarely. Tighten V-band clamp
to 15 - 30 in/lbs (85 - 170 cm/kg) of torque.
17. Install hoses onto fittings. If they do not slide on easily, apply
a small film of liquid hand detergent to the hose barbs.
18. Torque hose clamps to 50 in/lbs ( 280 cm/kg).
NOTE: Nylon-reinforced hose tends to cold-flow, so the clamps
will need to retorqued later. (The hose clamps do not actually
loosen, but rather the hose O.D. decreases!) It is best to give
them a final torqueing just prior to leaving the job site. Explain to
the customer that a further torqueing may be required the fol-
lowing day - and that a drip developing at a hose clamp is a
result of cold-flow and not poor workmanship.

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