SIHI Pump Repair.indd

Service and
Troubleshooting Guide
a publication of CEI Service & Parts Dept: 800.545.4034
Publication # 15-02-03
Rebuilding SIHI Centrifugal Pumps
used on CEI hot oil heaters
Pump Seals. Options include:
Radial Seal Rings, Mechanical
Seal or Seal-Less Magnetic Drive
Enclosed Impeller
Carbon Sleeve Bearing
Figure 1. The Sterling SIHI ZTNC/D hot oil pump is the standard circulating pump used on CEI hot oil heaters. It is designed
for thermal fluid temperatures of up to 662 degrees F. 29 sizes of this pump model are available. Radial seal rings are the
pump sealing option used by CEI.
Figure 2. Pump on a typical CEI Jacketed Firebox heater.
Figure 3. Pump on a typical CEI Helical Coil heater.
1
Ring Gasket Sizing
Parts and Tools
Required for Pump Rebuild
Section 1
Pump Model
CEI Part #
32-125
40-125
2515026-SIHI
50-125
40-200
50-200
2515044-SIHI
65-200
65-160
2515032-SIHI
Figure 6. Gasket sizing chart..
When ordering parts;
• Provide the pump model and serial number. These
numbers are found on the pump nameplate located
on the bearing housing. Be sure to include the
impeller size usually included in the model number.
(Example: ZNTC 50-160/130AA.002 where 130 is
the impeller size.
Figure 4. Required tools.
Tools:
• 5mm Allen wrench
• Flat Screwdriver
• 24mm wrench
• 18mm wrench
• 17mm wrench
• Marker
• Seal Installation Tool
• Emory Cloth
• Jaw Pullers
• Bearing Heater
• SIHI Pump Manual
• Snap Ring Pliers
• Pry Bar
• Oil Seal Pick Set
• Supply the item number, description and quantity of
the needed parts.
• Small Chisel
Parts:
Basic Rebuild Kit (see Fig. 7)
Quantity
Description
CEI Part #
7
Shaft Lip Seals
1506031-SIHI
1
Lock Washer
1506012-SIHI
1
Gasket, Shaft Housing
1506014-SIHI
1
O-Ring, Shaft Housing
1506015-SIHI
1
Retaining Ring
1506021-SIHI
1
Ball Bearing
2515027-SIHI
1
Gasket, Volute Casing
Figure 7. Basic rebuild kit.
*See sizing chart
(Fig. 6)
Full Rebuild Kit (see Fig. 8)
(Includes all parts above, plus shaft and bearing sleeve.)
1
Shaft
1506019-SIHI
1
Carbon Bearing Sleeve
1506028-SIHI
Figure 5. Pump rebuild kits & part numbers.
Figure 8. Full rebuild kit.
2
Section 2
Preparations before
Disassembly
Note: If the coupling is NOT a split coupling, remove the motor
from the baseplate.
• Place a drip pan under the pump and the piping
between the closed valves.
• Remove the foundation bolts in the support foot at
the rear of the pull out assembly.
The unit part description is identified by the tag located on
the top of the bearing bracket. Model number, serial number,
and impeller size are described. The model number is broken
down in the manual.
Section 3
Lock out the circulating pump motor
power supply and allow the pump to
cool before proceeding.
Disassembly
1. Remove rear pullout assembly from the volute casing
(Figure 9): Use the 18mm wrench to remove the six
nuts and washers that bolt the two sections together.
Note: A pry bar may be needed to separate the two
sections.
• Close the isolating valves on the suction and
discharge lines.
2. Remove the impeller: Use the 24mm wrench to
remove the impeller nut and tab lock washer. Then
use the jaw pullers to remove the impeller (Fig. 10).
• Mark the position of all parts (makes it easier to
reassemble).
• Disconnect the shaft coupling according to
instructions.
Total of 6 nuts
and washers
Volute casing
Impeller
Figure 9. Pump disassembly.
3
5. Replace lip seal rings. Assemble the following items
for lip seal ring removal and replacement:
• 6 SIHI lip seals
• Oil Seal Picks
• SIHI seal gauge
• Small screwdriver or chisel
• Lightweight hammer
• Seal installation tool
Remove the seals: Insert the screwdriver (or
chisel) between the seal and shaft housing (Fig. 13).
Using a twisting motion, deform the seal ring, then
remove a metal encapsulated lip seal. Repeat for all 6
lip seals. Note: Seal picks can also aid in the removal of
the seal rings.
Figure 10. Removing the impeller with jaw pullers.
3. Remove the casing cover and shaft housing: Use the
17mm wrench to remove the bolts holding the shaft
housing to the bearing bracket. Then separate the
volute case cover from the shaft housing (Figure 11).
Note: The O-ring that seals the shaft housing may
require some levering and light tapping.
Figure 13. Removing lip seals.
Install the new lip seals: Inspect the shaft
surface for unusual wear under the seal rings – tracks
on the shaft are normal. Note: The shaft can be used
a second time by shifting the seal positions to ride on
a previously unused area of the shaft. See the note
following the next step.
Figure 11. Removing the casing cover and shaft housing.
4. Dismount the shaft housing: Use the 5mm wrench
to remove the 4 cap screws holding the shaft housing
to the volute case. Then separate the housing from
the case. (Figure 12).
Using the SIHI radial ring gauge and the seal
installation tool, install the new lip seal rings (Figure
14). The first 5 seal rings face the casing; the last seal
ring faces the bearing. Fill the spaces between the
rings with a high temperature grease.
Note: Use the RED end of the gauge to position rings on
a NEW shaft. Use the Blue end of the gauge to position
rings on an existing shaft. Remember a shaft can only be
reused one time.
5. Remove ball bearing shaft (with the bearing): Use the
10mm wrench to remove the bearing cover (Figure
15) then push the shaft with the ball bearing out of
the bearing bracket from the pump end.
Figure 12. Dismounting the shaft housing.
4
6. Remove the bearing: Use the snap ring pliers to
remove the bearing retaining clip from the shaft then
pull the bearing and spacer off of the shaft (Fig. 16).
Heating the bearing’s inner race helps with removal.
Note: The bearing must be withdrawn from the pump
end of the shaft.
IN
Checks Prior
to Reassembly
Section 4
5 4 3 2 1 Ring Number
Ring seal surface wear
• Impeller, cover, and volute casing surfaces must
be checked.
IN
Ring Number
Note: If the clearance is excessive then replacement wear
rings, an impeller and/or casing must be fitted.
For installation of Rings
with a New Shaft
1
Ring Number
2
1
3
2
4
3
5
ZTN RADIAL SEAL RING GAUGE
4
IN
5
For installation of Rings
with a New Shaft
• Measure the distance between the impeller and
the volute casing cover at 4 points around the seal
diameter. The allowable distance is 0.012” to 0.020”.
Shaft surface wear
Figure 14. Installing new lip seals.
• Check shaft surface under seal rings for wear, normal
wear under the tracks of the seals is expected and
when found replace the shaft.
Ball bearing cover
Note: The shaft may be used again by shifting the
position of the rings. This can only be done once for each
shaft. Use the SIHI radial seal ring gauge to correctly
re-position the rings.
Carbon sleeve bearing
• Check shaft sleeve and bearing bushing for visible wear.
• If possible check the concentricity of the sleeve and
the bushing to the center diameter of the cover.
• Maximum run-out should be 0.002".
• If necessary to replace, press the bushing and the
sleeve from the cover.
Figure 15. Removing ball bearing cover.
• Replace the new sleeve and bushing by applying
pressure to the metal sleeve only.
Important checks and notes
• Replace the cover gasket and shaft housing gasket in all
cases.
• Check O-ring for flat spotting, nicks, cuts, and
material degradation and abrasion.
• Never reuse any radial lip seal rings that have been
removed.
Figure 16. Removing bearing and spacer off of the shaft.
5
Section 5
Reassembly
Section 6
Installation
Once the pump is mounted, connected and aligned to the
motor and coupling, do the following:
1. Slide the spacer against the shaft shoulder and install
(from the pump end) new or cleaned bearing over
shaft firmly against spacer, heating the bearing first
for easy mounting. Install the bearing circlip with a
pair of snap ring pliers.
1. Remove the vent plug (with gasket) and fill the cavity
with the same heat transfer oil used in the heater.
Rotate the shaft and allow air to escape.
2. Install the bearing lip seal in the bearing bracket
(ensure the seal lip faces away from the bearing), then
press the bearing and shaft assembly into the bearing
bracket. Lightly pack the pre-cleaned bearing with
high temperature grease. Close the bearing cavity
with the cover and bolts using a 10mm wrench.
Grease Fitting
Pump Vent Plug
Note: If possible clamp shaft with the bearing bracket
installed (pump end up) in a soft jawed vice.
3. Ensure that the sealing face of the shaft housing
and the surface cover are clean and free of nicks
and scratches. Ensure that the cover has sleeve and
bushing installed and they are concentric.
4. Install or check installation of the new lip seals, and
new or checked O-ring in the shaft housing.
5. Place a new gasket in the shaft housing, then mount
the shaft housing complete with O-ring and lip seals
to the cover with Allen cap screws and washers using
5mm Allen wrench.
Figure 17. Grease fitting and vent plug.
2. Apply power to the pump motor and watch for a
bubble free stream of heat transfer oil coming out of
the vent plug.
Note: The shaft housing must be orientated so that the
pump vent plug (Fig. 17) will be higher than centerline
of pump shaft when pump is re-installed on the heater.
3. Turn the pump motor off then install and tighten the
vent plug and gasket.
6. Slide the cover and shaft housing over the shaft
carefully into place inside the bearing bracket. Be
careful not to damage the O-ring when it is being
inserted.
Maintenance and
Troubleshooting
Section 7
7. Secure the cover to the bearing bracket with bolts
using a 17mm wrench.
Bearings:
SIHI ZTN pump bearings consist of one outboard grease
lubricated ball bearing and one internal liquid flushed carbon
sleeve bearing. The ball bearing is lubricated at the SIHI
factory for initial operation and should be lubricated at the
following intervals, independent of size:
8. Install the key, impeller, and lock washer. Secure the
impeller nut using a 24mm wrench.
9. Install a new gasket to the sealing face and bolt the
assembly to the volute casing with bolts and washers
using an 18mm wrench.
1750 RPM:
3500 RPM:
2800 hours of operation
1600 hours of operation
Note: After 10,000 hours of continuous operation, (or two years
in the case of intermittent operation), replace or repack bearings.
6
Shaft Sealing:
The shaft is sealed by a series of six lip seals. Seal leakage will
occur at the acceptable rate of 15ml per hour (approximately
1 – 2 drops per minute). The medium pumped will be
confined in the drainage chamber between the seal area and
the ball bearing. Leakage must be continuously drained from
this chamber through the lower tapped hole. Do not plug the
lower tapped hole or the vent hole.
Note: The life of the lip seals is detrimentally affected by the
following factors:
1. Operation without initial venting
2. Failure to pack seal rings with
high temperature grease.
4. Operation above maximum recommended
temperature for extended periods.
5. Control of pump operation from suction side,
improper line sizes or plugs in the inlet line.
6. Air ingress to the pump when cooling.
To prevent failure caused by air in-rush, observe
the following procedure: Do not isolate the pumps
by closing both suction and discharge isolating
valves, unless repair is to be done. As heat transfer oil
cools, the volume can be reduced up to 30%. This
reduction in volume creates an internal vacuum,
leading to air in leakage.
3. Use of contaminated heat transfer oils.
Troubleshooting — Specific Problems
Problem / Symptom
Possible Cause
Solution
Lack of flow
Restricted inlet and/or discharge.
Install pressure gauges on inlet
and outlet. Check performance —
compare with performance curve.
Check motor speed. Check inlet
and outlet piping for restrictions —
clean line strainers, open valving as
necessary.
Improper piping.
Insufficient NPSH.
Improper motor speed.
Mod Motor does not move
Line restrictions.
Insufficient NPSH.
Improper piping.
Pump not operating at correct
speed or wrong rotation.
Monitor inlet and outlet pressures.
Check available NPSH. Remove
inlet line restrictions. Ensure
pump is operating on the curve —
check motor speed and replace if
incorrect. Correct shaft rotation to
clockwise when viewed from the
driven end. Modulate discharge
valve until pressure increases to
duty point. This ensures correct flow.
Pump stops pumping
Coupling or motor failure.
Inlet line restriction.
Impeller failure.
Pump vapor locked.
Check for shaft rotation and repair
motor or coupling as necessary.
Check motor operating speed
and check pump shaft for binding.
Check motor for single phasing.
Ensure pump is flooded and inlet
lines are full of thermal fluid.
Pump is noisy or vibrates
Improper alignment.
Insufficient NPSH.
Fouling of the rotating assembly.
Bearing failure.
Check alignment. Listen for bearing
noise and replace if any is heard.
Check for fluid contamination.
Check NPSH by measuring inlet and
outlet pressures. Calculate available
NPSH and compare with pump
curve.
Troubleshooting — Specific Problems (continued)
Problem / Symptom
Possible Cause
Solution
Motor is overloaded
Improper motor size.
Improper fluid temperature.
Wrong fluid.
Shaft not free to rotate.
Failed bearing(s).
Operation outside the pump curve.
Check inlet and outlet pressures.
Compare to performance. Adjust
as necessary. Ensure temperature
is per design. Check pumped fluid
specific gravity. Check motor sizing.
Rotate pump and motor shaft by
hand — free as necessary. Check
pump bearing —
­ replace if tight
or worn. Check available NPSH at
specific operating points.
Pump leaks in excess of 1 to 2 drops
per minute
Lip seal failure due to wear of
mis-operation, including improper
venting at startup. Insufficient cooling due to foreign material buildup
on pump body. Improper motor
(TEFC required). Wrong coupling
guard. Restricted cooling flow or too
high surrounding temperature. Grit
or dirt in the thermal fluid. Sleeve
bearing wear.
Clean pump case. Ensure
unrestricted airflow from motor fan
across pump. Ensure surrounding
temperature is 140°F (60°C). Replace
coupling guard if it restricts airflow.
Replace motor if fan does not blow
toward pump. Check thermal fluid
for solids — replace if contaminated.
Seals worn due to misalignment
— replace and realign. Check shaft
for end play and wear at the lip seal
area. Replace lip seals.
High bearing temperature
Improper installation, including
wrong motor type. Too high
surrounding temperature. Restricted
airflow across pump. Improper
alignment. Lack of bearing grease.
Over-greased bearing. Plugged
bearing cavity vent and drain.
Remove airflow restrictions and
clean pump body. Install nonrestrictive coupling guard. Ensure
motor fan is operational and
undamaged. Plumb a drain into the
bearing cavity vent port and drain it
to a small catch can. Check grease
conditions in pump and grease
cavity — grease or remove excess
as necessary. Align pump and motor.
CEI Service
& Parts: 800.545.4034
245 Woodward Rd. SE | Albuquerque, New Mexico 87102 | USA
©2015 CEI Enterprises, Inc.
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