Service and Troubleshooting Guide

Publication # 15-02-03

a publication of CEI Service & Parts Dept: 800.545.4034

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Rebuilding SIHI Centrifugal Pumpsused on CEI hot oil heaters

Carbon Sleeve Bearing

Pump Seals. Options include: Radial Seal Rings, Mechanical Seal or Seal-Less Magnetic Drive

Enclosed Impeller

Figure 2. Pump on a typical CEI Jacketed Firebox heater. Figure 3. Pump on a typical CEI Helical Coil heater.

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.

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Section 1 Parts and Tools Required for Pump Rebuild

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

• Small Chisel

Parts:

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.

• Supply the item number, description and quantity of the needed 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 *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

Ring Gasket SizingPump Model CEI Part #

32-125

2515026-SIHI40-125

50-125

40-200

2515044-SIHI50-200

65-200

65-160 2515032-SIHI

Figure 4. Required tools.

Figure 7. Basic rebuild kit.

Figure 8. Full rebuild kit.Figure 5. Pump rebuild kits & part numbers.

Figure 6. Gasket sizing chart..

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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 Disassembly1. 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.

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).

Section 2 Preparations before Disassembly

Lock out the circulating pump motor power supply and allow the pump to cool before proceeding.• Close the isolating valves on the suction and

discharge lines.

• Mark the position of all parts (makes it easier to reassemble).

• Disconnect the shaft coupling according to instructions.

Figure 9. Pump disassembly.

Volute casing

Impeller

Total of 6 nuts and washers

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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.

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).

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.

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.

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 10. Removing the impeller with jaw pullers.

Figure 11. Removing the casing cover and shaft housing.

Figure 13. Removing lip seals.

Figure 12. Dismounting the shaft housing.

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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.

Section 4 Checks Prior to Reassembly

Ring seal surface wear • Impeller, cover, and volute casing surfaces must

be checked.

• 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”.

Note: If the clearance is excessive then replacement wear rings, an impeller and/or casing must be fitted.

Shaft surface wear• Check shaft surface under seal rings for wear, normal

wear under the tracks of the seals is expected and when found replace the shaft.

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.

• 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.

IN

Ring Number5 4 3 2 1

For installation of Rings with a New Shaft

IN

Ring Number5 4 3 2 1

For installation of Rings with a New Shaft

IN

Ring Number54321

ZTN RADIAL SEAL RING GAUGE

Ball bearing cover

Figure 14. Installing new lip seals.

Figure 15. Removing ball bearing cover.

Figure 16. Removing bearing and spacer off of the shaft.

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Section 5 Reassembly

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.

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.

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.

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.

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.

7. Secure the cover to the bearing bracket with bolts using a 17mm wrench.

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.

Section 6 InstallationOnce the pump is mounted, connected and aligned to the motor and coupling, do the following:

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. Apply power to the pump motor and watch for a bubble free stream of heat transfer oil coming out of the vent plug.

3. Turn the pump motor off then install and tighten the vent plug and gasket.

Section 7 Maintenance and Troubleshooting

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:

1750 RPM: 2800 hours of operation 3500 RPM: 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.

Figure 17. Grease fitting and vent plug.

Grease Fitting Pump Vent Plug

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.

3. Use of contaminated heat transfer oils.

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.

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. 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.

Insufficient NPSH.

Improper piping.

Pump not operating at correct speed or wrong rotation.

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.

CEI Service & Parts: 800.545.4034245 Woodward Rd. SE | Albuquerque, New Mexico 87102 | USA

©2015 CEI Enterprises, Inc. 8

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 cool-ing 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 non-restrictive 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.