Circor IMO CFHN Series User manual

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CFHN SERIES
PRODUCT SERVICE MANUAL
Metric standards apply for all pumps covered by this manual with regard to
Mounting dimensions, external connections, bolts, bolt threads, plugs and bearings.
WARNING
This manual AND the following CE-compliant manuals should be read thoroughly, and in their entirety,
prior to pump installation, operation and maintenance:
Manual No. SRM00100 – Safety and Operation Manual.
Manual No. SRM00101 – Installation, General Maintenance and Trouble Shooting Manual.
Electronic copies of all referenced manuals can be obtained at www.imopump.com.
Manual No. SRM00103 Rev. 02 (21-0001) October, 2021

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READ THIS ENTIRE PAGE BEFORE PROCEEDING
FOR SAFETY OF PERSONNEL AND TO PREVENT DAMAGE TO THE EQUIPMENT,
THE FOLLOWING NOMENCLATURE HAS BEEN USED IN THIS MANUAL:
Warning Level Risk Level Consequences of disregarding the warning
DANGER Immediate Acute Risk Death, Serious Bodily Harm
WARNING Potential Acute Risk Death, Serious Bodily Harm
CAUTION Immediate Hazardous
Situation Minor Bodily Harm, Material Damage
i NOTE Potentially Hazardous
Situation Minor Bodily Harm, Material Damage
Symbol Meaning
Safety Warning – Take note of all information highlighted by a Safety Warning Sign
and follow the instructions to avoid damage to equipment, injury to personnel or
death.
Electrical Hazard – Contact with electrical equipment can cause shock. Contact of
electrical equipment with water can cause shock. Do NOT touch with wet hands.
Always disconnect when not in use.
CONTENTS
Cover Sheet .......................................................................................................................................................... 1
Safety and Table of Contents................................................................................................................................ 2
General Instructions .............................................................................................................................................. 3
Pump Model Identification ..................................................................................................................................... 3
Description of the Equipment ................................................................................................................................ 4
Ordering Instructions ............................................................................................................................................. 4
Operation and Operating Limits ............................................................................................................................ 4
Spare Parts and Kits ............................................................................................................................................. 5
Inspection .............................................................................................................................................................. 6
Pump Maintenance ............................................................................................................................................... 6
Pump Disassembly Instructions ............................................................................................................................ 6
Pump Assembly Instructions ................................................................................................................................. 8
Installation, Alignment and Troubleshooting ......................................................................................................... 9
Field and Factory Service / Parts .......................................................................................................................... 9
Pump Assembly Drawings .................................................................................................................................. 10
IMPORTANT NOTE
If operation of pump is critical to your business, we strongly recommend keeping a spare pump in stock at all
times. As a minimum, a minor repair kit (O-rings, gaskets, shaft seal, bearings and retainers) should be kept in
stock so pump refurbishment can be readily accomplished after inspection.

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A. GENERAL INSTRUCTIONS
Instructions found herein cover disassembly, assembly and parts identification of all size CFHN series Imo 3-screw
pumps, sizes 20 through 330.
NOTE: Individual contracts may have specific provisions that vary from this manual. Should any questions arise
which are not addressed in this manual, refer to contract and to Manual No.’s SRM00100 and SRM00101.
See front cover for manual descriptions. For additional information/technical assistance please contact
Technical Service Department of Imo Pump at [phone].
Every effort was made to prepare text of manual so engineering and design data is transformed into most easily
understood wording. Imo Pump must assume personnel assigned to service pump have sufficient technical
knowledge and are experienced to apply sound safety and operational practices which may not be otherwise covered
by manual.
WARNING
If instructions in this manual are not correctly and strictly followed and observed, injury to personnel or serious
damage to pump could result. Imo Pump cannot accept responsibility for unsatisfactory performance or damage
resulting from failure to comply with instructions.
B. INTRODUCTION
This manual covers only CFHN series pumps. These pumps have been designed for general use in
lubricating, seal and distillate fuel oil applications. Size and construction of each pump is identified in
model number on pump nameplate. Definitions of model designators are identified in Figure 1.
Figure 1 – Model Designator Definitions
CFH N020 R46 K C /000
CFH
020 040 060 090 140 170 330
31 ●
34 ●
20
37 ●
38 ●
39 ●● ● ●
46
41 ●
42 ●
46 ●●●●●●●
Size 20 Only: K = Axial Facing Inlet, M = Radial Facing Inlet
Example 
Design Series
Size / Flow Rate Designator
Rotor Thread Pitch Angle (degrees)
C = ISO Flange Mount, F = Foot Mount
Special Option Designator
/000
This designator is not present for standard pump models
All Sizes Above 20: P = Axial Facing Inlet, S = Radial Facing Inlet
Design Sequence
N
Facing Drive Shaft: R = CW, L = CCW
Direction of Drive Shaft Rotation*
Inlet Port Configuration
Size / Flow Rate Designator
Rotor Thread
Pitch Angle (°)
C F H N M o d e l N o m e n c l a t u r e
* R (CW) shaft rotation direction is considered "standard", however,
L (CCW) rotation is offered for all available combinations of size and
thread pitch angle.
N = 40 bar version
C
Mounting Configuration
R
K
All are SAE 4-bolt Mounting Pads - drilled & tapped for metric bolts
Note
All pumps models except Size 20 have weep holes that will readily allow for
detection and collection of any mechanical seal leakage that might occur.
Available Size & Thread Pitch Angle Combinations*

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C. DESCRIPTION OF EQUIPMENT
CFHN series pumps are positive displacement, rotary screw pumps consisting of a precision bored housing that
encloses a drive screw (power rotor) and two intermeshing driven screws (idler rotors). These screws, when
rotating, form a succession of closures or cavities. As they rotate, fluid is moved axially from inlet to outlet port in a
continuous, uniform flow with minimum fluid pulsation and pump noise.
NOTE: CFHN pumps are NOT bi-rotational; Inlet and outlet ports can NOT be reversed.
D. ORDERING INSTRUCTIONS
All correspondence pertaining to replacement parts for equipment must refer to instruction manual number and
should be addressed to nearest Imo pump representative. Handling of replacement part orders will be greatly
facilitated if directions below are carefully observed:
1. Provide number of instruction manual with revision level and date.
2. Provide model number of the pump for which part is desired. Number appears on nameplate.
3. Designate desired part by Position No. and name as shown on assembly drawing and as listed in Table 2 below.
E. OPERATION
E.1 – LIQUID LIMITATIONS
E.2 – OPERATING LIMITS
CAUTION
Operating conditions, such as speed, fluid viscosity, temperature inlet pressure, discharge pressure, filtration,
duty cycle, drive type, mounting, etc., are interrelated. Due to these variable conditions, specific application limits
may be different from that of operational limitations. Equipment must not be operated without verifying that
system’s operating requirements are within pump’s capabilities.
Table 1 – Pump Operating and Structural Limits
Maximum Speed ...........................................................................................................5000 RPM for size 20 models
............................................................................................... 4000 RPM for size 40 to 170 models
..................................................................................................................3600 RPM for 330 model
Viscosity .........................................3,200 cSt (15,000 SSU) maximum / 2.0 cSt (32.6 SSU) minimum for all models
NOTE: Do not alter design viscosity without prior consultation with Colfax Pump. Consult factory
for allowable operating viscosities at specific speeds and pressures.
Temperature..................................................................................................................... -18° to 107°C / 0° to 225°F
Inlet Pressure – Maximum ............................................................................................................ 3.4 bar-g / 50 psig
Differential Pressure – Maximum ................................................................................................... 41.4 bar / 600 psi
Discharge Pressure – Maximum ............................................................................................... 41.4 bar-g / 600 psig
Drive ........................................................................................................................................................... direct only
Filtration .................................................................................... See Manual SRM00101 (description on front cover)
Mounting ................................................................................................................................. foot or flange mounted
Shaft Rotation ....................................................................................................... available in CW or CCW versions
NOTE: Pump is not bi-rotational
CAUTION
Pump is designed for liquids having general characteristics of oil including requirement for at least some lubricity.
Since pump ball bearing is lubricated by pumped liquid due to open ball bearing design, never operate CFHN
pumps with a liquid having a viscosity less than 2.0 cSt (33 SSU).
Never operate pump on water.

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F. PARTS LIST
Part number identifiers (POSITION NUMBERS / POS. NO.’s) contained in Table 2 refer to circled numbers shown on
assembly drawings, Figures 4, 5 and 6.
Table 2 – Parts List
POS.
NO. QTY DESCRIPTION
POS.
NO. QTY DESCRIPTION
1 1 Housing 15 X 1 Retaining Ring
2 1 Inlet Cover 16 X 1 Seal
3 0, 2, 4 or 8 Bolt (See Note) 20 1 Bracket (Foot Mount Pumps Only)
4 1 Inboard Cover 21 2 Bolts for Foot Bracket
6 4,6 or 8 Bolt (See Note) 26 X 1 O-Ring (size 40 to 90)
7 1 Power Rotor 31 X 1 O-Ring (Qty 2 on size 20 Pumps)
8 2 Idler Rotor 47 2 Plug
11 1 X Ball Bearing 95 1 Pin
13 1 Key
X = Minor Repair Kit Item
Note: POS. NO. 3: Qty 4 on axial inlet versions of all pump sizes 20 through 330.
POS. NO. 3: Qty 2 on right angle inlet versions of size 20 pumps.
POS. NO. 3: Qty 0 on right angle inlet versions of size 40 through 90 pumps.
POS. NO. 3: Qty 8 on right angle inlet versions of size 140 through 330 pumps (Qty 12
on Foot Mount versions)
POS. NO. 6: Qty 6 on right angle inlet versions size 20 pumps.
POS. NO. 6: Qty 8 on right angle inlet versions of sizes 40 through 90.
G. INSPECTION
Interval for inspection and replacement of worn parts varies with properties of pumped liquid and can only be
determined by experience. A worn pump will be noticeable by excessive vibration, noise, reduction in flow output
and/or reduction in system pressure.
CAUTION
All CFHN Series internal pump parts, including ball bearing, are lubricated by pumped liquid. Pumping a liquid
which contains abrasive materials, that is too low in viscosity or lubricity, or that is corrosive, will significantly
reduce service life and call for shorter service intervals.
H. PUMP MAINTENANCE
WARNING
Failure to observe precautions while installing, inspecting, and maintaining the pump can cause injury to
personnel from accidental handling, e.g.: Liquids that may harm skin or clothing, fire hazard risks from flammable
liquids, or injury from high pressure fluid jets.
DANGER
BEFORE working on equipment, be sure all power to the equipment is disconnected and locked-out.

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H.1 – GENERAL COMMENTS
Part number identifiers (POSITION NUMBERS / POS. NO.’s) within parenthesis such as (8) refer to circled numbers
shown on assembly drawings, Figures 4, 5 and 6.
NOTE: If upon disassembly, significant wear on power or idler rotors or rotor housing is found, Imo Pump
recommends replacement of entire pump.
H.2 – TOOLS REQUIRED
Procedures described in this manual require common mechanics hand tools, arbor press, torque wrench and
suitable lifting device such as sling for smaller pumps or strap for larger models.
H.3 – PUMP DISASSEMBLY
Perform the following steps before disassembling pump:
a) If pump is driven by an electric motor, de-energize and lock out power to driver and tag power control
box “WARNING - Out of Service”. Proceed similarly for other type drivers.
b) Close all inlet and outlet valves and tag valves “WARNING - Out of Service”.
c) Vent pressure in pump and drain pumped liquid.
d) Remove pipe fittings/flanges at pump inlet and outlet openings.
e) Remove bolts holding pump to its mounting.
f) Remove coupling hub and key (13) from power rotor (7) shaft and place pump on suitable workbench.
NOTE: CFHN Series pumps incorporate highly finished precision parts that must be handled carefully to avoid
damaging critical machined surfaces. Removed parts should be tagged for identification and their exact
positions in pump should be noted so new and removed parts can be properly replaced.
CAUTION
When removing inboard cover (4) from pump, DO NOT pull out power rotor (7) and idler rotors (8) at same time
since they may drop out and be damaged. If rotors start to come out, hold them in place.
1. Remove inboard cover (4) from pump housing (1) after first removing bolts (3 or 6) from cover (4).
2. Remove O-ring (31) and stationary seat (see Figures 2 and 3) of seal (16) from inboard cover (4).
CAUTION
In next step, rotors will be removed from pump. They will come out as a unit. Use care to support rotor set as it is
withdrawn from housing so idlers will not be dropped on floor.
3. Remove rotor set, power rotor (7) and two idler rotors (8), from pump by grasping and gently pulling on drive shaft
end of power rotor (7). When ends of idler rotors (8) clear discharge end of housing (1), hold all 3 rotors together
and ease out as an assembly. Once rotor assembly is removed, disengage both idler rotors (8) and set aside.
4. Mechanical Seal Removal - See Figures 2 and 3 below.
a. For Elastomer Bellows Type – Figure 2 – Slide rotating assembly off power rotor (7).
b. For Metal Bellows Type Seals – Figure 3 – Loosen set screw(s) at least 2 turns and slide rotating assembly
from power rotor
NOTE: If only replacing seal, skip to Steps 3 through 10 in PUMP ASSEMBLY / REASSEMBLY section below to
install new seal and complete pump reassembly.
If remainder of pump needs to be disassembled, proceed with Step 5 immediately below.
WARNING
Fluid leakage may make floor slippery and cause personal injury when pump is removed from system or when it
is disassembled.

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Figure 2 Figure 3
Elastomer Bellows Mechanical Seal Metal Bellows Mechanical Seal
5. Remove ball bearing (11) from power rotor (7) by first removing retaining ring (15) from groove in power rotor (7)
shaft. Ball bearing (11) can then be removed with a gear puller or arbor press.
CAUTION
Removal of bearing by force applied to its outer ring could damage bearing.
NOTE: Imo Pump strongly recommends replacing ball bearing every time it is removed from power rotor.
6. Remove inlet head (2) after first removing four bolts (3 or 6) from inlet head (2).
7. Remove O-ring (26 or 31, depending on pump size) from inlet head (2).
H.4 – PUMP ASSEMBLY / REASSEMBLY
NOTE: Prior to pump assembly, all parts should be cleaned and inspected for nicks, burrs or gouges. When
ready for assembly, wipe all parts, including bolts, O-rings and seal faces with a clean, lubricating oil
or pumped product, if applicable.
CAUTION
Bearing service life could be significantly reduced if pushed onto shaft by outer ring.
1. Install ball bearing (11) onto shaft (7) using an arbor press and sleeve by pushing on ball bearing (11) inner ring
only until ball bearing (11) is positioned against shoulder on power rotor (7).
2. Install retaining ring (15) in groove into power rotor (7).
3. Before installing seal (16), insure power rotor (7) shaft is clean and has no burrs or sharp edges.
CAUTION
To avoid seal leaks, avoid contacting sealing faces of mechanical seal with any objects, including fingers.
Objects can scratch sealing surfaces. Acids in finger oils can etch them.
4. Mechanical Seal (16) Installation – See Figures 2 and 3 above.
Clean and Lubricate Sealing Face – Clean sealing faces of rotating assembly and stationary seat with alcohol and
lint free cloth. Apply light film of clean lubricating oil to both sealing faces.
ROTATING ASSEMBLY
Seals with Elastomer (rubber-like) Bellows – Apply light film of oil to elastomer bore of rotating assembly and
push it onto power rotor (7) shaft with twisting motion. Do not allow fingers to touch sealing face.
Seals with Metal Bellows – Apply light film of clean lubricating oil to O-ring in rotating assembly bore and push
onto power rotor shaft (7) with a rotating motion. For size 20 only, make sure slots in rotating assembly line up
with seal return hole in power rotor shaft (7). Tighten seal setscrew(s).

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STATIONARY SEAT
Apply light film of clean lubricating oil to O-ring on outer diameter of stationary seat. Install stationary seat into
bore in inboard cover (4) with fingers so slot in non-running face of seal is facing into inboard cover (4). Do not
touch sealing face with fingers or any tools. Be sure stationary seat is all the way to bottom of bore in inboard
cover (4) and slot in seal mates up to pin (95).
RE-CLEAN / RE-OIL SEALING FACES – Do this only if faces accidentally touched during installation process.
5. Mesh two idler rotors (8) and power rotor (7) together into a rotor assembly making sure ends of idler rotors are
properly engaged into slots in power rotor.
6. Install rotors by positioning pump housing in a vertical position and sliding rotor assembly into housing bore (1)
until ball bearing (11) bottoms out in housing bore.
7. Lubricate and install O-ring (31) in groove in inboard cover (4).
8. Install inboard cover (4) on housing (1).
CAUTION
To maximize seal life, seal vent in cover must be oriented at 12:00 o'clock when pump is horizontally mounted in
its installed position. Vent orientation not critical when unit is vertically mounted.
9. Install four bolts (3 or 6) into inboard cover (4) and thread bolts into housing (1). Torque bolts to value shown on
assembly drawing (Figures 4, 5 or 6).
10. Install O-ring (31) in groove in inlet head (2).
11. Install inlet head (2) onto housing (1) with cap screws (3 or 6).
12. Install key (13) into keyway on drive end of power rotor (7). If appropriate, install drive coupling over key (13) and
drive end of power rotor (7).
I. INSTALLATION, ALIGNMENT AND TROUBLESHOOTING
Install coupling to pump drive shaft. Align pump and driver shafts per Manual SRM00101.
Connect piping to pump. Open inlet and outlet line valves. Vent air from seal chamber before starting pump by
opening pipe plug at inboard end of pump until oil comes out. This will assure that seals are lubricated at startup.
DANGER
3-screw pumps are positive displacement types. They must NOT be started with blocked outlet lines.
For detailed instructions regarding installation, alignment, operation general maintenance and trouble shooting, see
Manuals SRM00101.
J. FIELD AND FACTORY SERVICE / PARTS
Imo Pump maintains a staff of trained service personnel that can provide pump installation, pump start-up,
maintenance/overhaul and troubleshooting supervision as well as installation and maintenance training.
Our factories have facilities and personnel to inspect, maintain, overhaul and test pumps in the event user prefers to
return pumps for these services. Pumps that have been factory-overhauled are normally tested and warranted “as-
new” for a period of one year from date of shipment.
For either field service or factory overhaul assistance, contact your local Imo Sales Office or representative at the
Technical/Customer Service Department in Monroe, NC, USA, [phone].
Minor Repair Kits are available for CFHN series pump models. Minor Repair Kits are used to repair leaking seals,
rough or failed bearings and/or for re-assembly after pump tear-down. They include (as applicable) mechanical
seals, O-rings, bearings and any part that might be damaged during disassembly (e.g., retainer rings). Kits contain
all necessary parts. Individual parts within Minor Repair Kits are not sold. If major pump components (e.g., rotors or
housings) are heavily worn or damaged, entire pump should be replaced.

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Figure 4
CFHN020 Pumps

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Figure 5
CFHN040, 060 and 090 Pumps
10

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Figure 6
CFHN140, 170 and 330 Pumps
METAL BELLOWS MECHANICAL SEAL
ELASTOMER BELLOWS
MECHANICAL SEAL WITH SPACER
12 O'CLOCK
3 O'CLOCK
6 O'CLOCK
9 O'CLOCK
OUTLET
INLET
NOTES:
1. TO MAXIMIZE SEAL LIFE, SEAL VENT MUST BE ORIENTED UPWARD (12 O'CLOCK)
WHEN PUMP IS HORIZONTALLY MOUNTED IN IT'S INSTALLED POSITION. VENT
ORIENTATION NOT CRITICAL WITH VERTICAL MOUNTING.
2. THESE PARTS FOR FOOT MOUNT OPTION ONLY.
INLET
OUTLET
SECTION A-A
1/16 MAX
47
8
WEEP
SEAL VENT
3
95
95
TORQUE TO
61 N·M +/- 7 N·M
3
3
47
16
4
7
13
15
11
31
26
1
2
16
16
AA
3
SEE NOTE 2
20
ELASTOMER
SEAL
BELLOWS
MECHANICAL
MAX1/16
SEE
NOTE 3
3. INLET COVER DRAIN PLUGS ONLY PRESENT ON SOME SPECIAL MODELS.
[ 45 FT-LB +/- 5 FT-LB ]
HOLE
TORQUE TO
61 N·M +/- 7 N·M
[ 45 FT-LB +/- 5 FT-LB ]
TORQUE TO
[ 45 FT-LB +/- 5 FT-LB ]
61 N·M +/- 7 N·M
3
VIEWS SHOWING AXIAL SAE 4-BOLT INLET
SEAL VENT

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CIRCOR
1710 Airport Road
PO Box 5020
Monroe, NC USA
28111.5020
Tel: [phone]
Email: [e-mail]
Web: www.circorpt.com
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