Grundfos Marine Pump
Spare Parts Supplier
CR, CRN and CRT multistage pumps, NB/NK end-suction and TP in-line units on fire, boiler feed, cooling and utility duty — identified from the type designation and the code line on the plate, then quoted by OEM route or verified alternative.
The Grundfos pumps a ship actually carries
Grundfos, based in Bjerringbro, Denmark, sells one marine range covering the engine room, general services and utilities. Its own marine literature ties each family to a duty on board, and the cards below keep to those ties. Several of the letter codes are also used by other makers, so the maker's name on the plate is part of the identification, not a formality.
CR
Grundfos describes CR pumps as multistage in-line pumps, and its marine range lists them for fire and general service, boiler feed, thermal oil, freshwater generator and freshwater cooling duty. The hydraulic end is a stack of chambers and impellers between base and pump head, with neck rings in the chambers and a bearing ring in some of them. Enquiries centre on the shaft seal, chamber-stack parts, the coupling and the O-rings.
CRN
The CRN keeps every part in contact with the pumped liquid in stainless steel. For marine and offshore service Grundfos offers the model GS, in which the parts outside the liquid are upgraded to stainless steel as well. The CRN is built in several material variants, among them G, GI, GX and GS, so the material code in the designation is copied with the rest of the line.
CRT
The titanium member of the CR family, which Grundfos lists for scrubber cooling and ejector pump duty in the engine room and describes as suitable for seawater. Grundfos covers a CRN and a CRT of the same size in one set of service instructions, so the range letters, not the frame size, tell the materials apart, and a chamber or a seal is never matched on size alone.
NB · NBG · NK
NB and NBG are single-stage volute pumps with an axial inlet and a radial outlet; Grundfos groups them with the NK as end-suction pumps for freshwater cooling and HVAC on board, in cast iron and duplex steel. NB complies with EN 733 and NBG with ISO 2858. Impellers, wear rings, shaft seals and pump-cover O-rings are the recurring lines, and the material code in the designation sets what the impeller and the wear ring are made of.
TP · TPD
Close-coupled in-line pumps with a rigid shaft, which Grundfos lists for freshwater cooling and HVAC service on ships. TPD is the twin-head version, so the request states which head the parts are for. The pump plate prints the actual impeller diameter, and an E after the range letters, as in TPE, marks an electronically speed-controlled pump.
CM · Hydro MPC · SEG · SEV · DDE · DME
The marine range also reaches utility systems: CM pumps on freshwater generator and chilled water service, Hydro MPC booster sets, SEG and SEV sewage pumps and the DDE and DME digital dosing pumps. For a booster set or a dosing system, send the system designation together with the plate of the unit that has failed.
Where a Grundfos pump comes back for parts
The service and operating instructions Grundfos publishes for its multistage and end-suction pumps keep returning to a short list: the shaft seal, the rings that keep one stage from leaking into the next, the bearings inside the stack, and every joint broken when the pump is opened.
A seal matched to the duty
Grundfos describes its mechanical seals as maintenance-free precision components whose faces are lubricated by the pumped liquid, matched to the conditions the pump was sold for. It warns against running the pump dry or against a closed valve, and when the seal of a recently installed pump fails early, it names improper installation or handling as the main cause. Once the sliding faces are damaged, the whole seal is replaced.
Neck rings and wear rings
Neck rings in the CR chambers limit leakage from one stage back to the impeller inlet, and the CR 32 to 90 service instructions also renew a wear ring pressed over the impeller skirt. As these rings open up, liquid slips back between stages and the pump loses head while the motor keeps turning. Grundfos wear-part kits carry the neck rings together with their retainers.
Bearing rings and bushes
Chambers with a bearing hold a bearing ring and a bush. The service instructions measure the bush against the shaft and the bearing ring against its driver, and the parts are replaced once the stated tolerance is exceeded, so bearing rings and bushes are best listed together with the neck rings rather than ordered on their own.
O-rings and gaskets every time
Grundfos instructs that gaskets and O-rings are always replaced when a pump is overhauled, and the CR assembly sequence renews the pump-housing O-ring and the rubber springs with them. A seal or chamber order placed without these leaves the pump waiting on its smallest items.
Coupling and shaft height
When a CR coupling is refitted, the service instructions hold the seal in place with an adjusting fork, set the top of the pump shaft flush with the bottom of the coupling and check that the gaps either side of the coupling halves are equal. Those steps fix the working position of the seal, so coupling halves and screws are worth a line whenever the seal is renewed.
Grundfos parts that appear on request lines
The list follows the position numbers used in Grundfos service instructions — shaft seal, chamber stack, bearings, joints, coupling — so each request line can carry its position number next to the description.
- Shaft seals and shaft seal kits, matched by the four-letter seal code
- Complete chamber stacks, made up to the stage count of the pump
- Chambers, intermediate chambers and chambers with bearing
- Neck rings with neck ring retainers
- Impellers, and the impeller wear rings fitted on CR 32 to 90
- Bearing rings, bushes and retaining rings
- Split cones and split cone nuts
- Pump-housing and seal O-rings, gaskets and rubber springs
- Couplings, coupling guards and screws
- NB and NBG impellers, wear rings and pump-cover O-rings; TP impellers and neck rings
- Staybolts, outer sleeves, bases and pump heads
- Complete replacement pumps to the full type designation
Reading a Grundfos plate for a request
A Grundfos pump plate carries two lines that matter more than the rest: the type designation and the model or identification-code line beneath it. That line brings together the service-model letter, product number, production site, production year and week and, on newer plates, the serial number, in an order that differs between plate generations, so a photograph of the whole line is worth more than a retyped extract.
- Type designation exactly as stamped, every code group included, with the four-letter seal code
- The model or identification-code line photographed whole: service-model letter, product number, production site, year-and-week code and, where printed, serial number
- Maker name, and the Bjerringbro, Denmark line where the plate carries one, which separate a Grundfos NB or CM from same-letter ranges of other makers
- Stage count: the figure after the hyphen on current CR and CRN plates; on older plates that figure is the stage count times ten
- Actual impeller diameter as printed on NB, NBG and TP plates
- Pressure rating, maximum temperature and rated speed as stamped
- Motor nameplate photographed separately, together with the plate of any speed-control unit
- Position numbers from the Grundfos service instructions or parts list for each item
- Pumped liquid and duty: fire, boiler feed, cooling, scrubber or utility service
- Whether the original pump came with a certificate or test report, as shown in the pump-version code
Tools for this equipment: the end-suction pump size reader for a size such as NK 50-250/241, the mechanical seal material code for the seal faces, the flange identifier for the suction and discharge flanges, and the affinity laws calculator when a centrifugal pump runs on another supply frequency. Where the seal follows EN 12756 dimensions, the mechanical seal size finder works from the shaft diameter or the measured installation length.
How a Grundfos request is checked
Grundfos builds the CR range as a modular system, and much of what decides a part is printed on the plate rather than hidden in a drawing. The checks below use that before any supplier is contacted.
Seal code before seal price
A shaft seal is matched from the four-letter code and the pump designation, not from a description. A request for a mechanical seal for a CR without the plate is queried back before it goes any further.
Service model with product number
Grundfos issues service instructions and kits per service model, and the model letter is not part of the type designation. It is read from the model or identification-code line together with the product number before any kit is named.
Stage count settles the stack
Grundfos lists complete chamber stacks and wear-part kits by number of stages. When several stages are worn, a complete stack and individual parts are compared openly on the quotation.
Certificates stated, not assumed
Fire pumps and other classed duties may need a certificate with a replacement unit. Grundfos marks certificates and test reports in the pump-version code, and the buyer's requirement is confirmed with the supply route before a price is given.
OEM route or verified alternative
Seals, O-rings and wear parts are quoted by OEM route, or as a verified alternative where the buyer accepts one, and the quotation states which of the two it is.
Grundfos pump enquiries — recurring questions
What do the four letters of the seal code in a Grundfos type designation mean?
They are the shaft-seal code. On CR, CRN and CRT pumps it is the last group of the designation; on NB and TP pumps further codes follow it. The first letter gives the seal type, for example H for a balanced cartridge seal with O-ring or B for a rubber bellows seal. The second and third give the rotating and stationary face materials, such as Q for silicon carbide or U for tungsten carbide, and the fourth gives the rubber, such as E for EPDM or V for FKM. HQQE therefore reads as a balanced cartridge seal with silicon carbide faces and EPDM rubber parts.
Where is the production date on a Grundfos pump plate?
In the model or identification-code line under the type designation. Next to the service-model letter, the product number and the production-site code it carries four digits in year-and-week form: 2243, for example, means week 43 of 2022. Send a photograph of the whole line, because its order differs between plate generations.
Can CR chamber-stack parts be ordered without the stage count?
Not reliably. Grundfos lists complete chamber stacks and wear-part kits by number of stages. On current CR and CRN type keys the figure after the hyphen is the stage count; older plates give the stage count times ten, followed by a slash and the impeller count when the pump has fewer impellers than chambers. The full designation, the product number and the service-model letter together identify the stack.
Is a Grundfos NB the same pump as an Allweiler NB?
No. Both makers use NB for a centrifugal range built to EN 733, so the letters alone do not identify the pump. Read the maker's name on the plate: the Grundfos plates shown in its manuals carry the Bjerringbro, Denmark line, and a Grundfos NB designation gives the nominal and the actual impeller diameter either side of the slash.
Which Grundfos pumps are found in a ship's engine room?
Grundfos's own marine literature lists CR for fire and general service, boiler feed, thermal oil and freshwater generator duty; CRT for scrubber cooling and ejector pumps; NB/NK, TP and CR for freshwater cooling; CM and Hydro MPC on chilled water; and SEG and SEV pumps on sewage. The marine pump parts overview covers other makers on the same systems.
Is Vessel Core connected to Grundfos?
No, and there is no agreement of any kind. Vessel Core holds no distribution, representation or partnership agreement with Grundfos, and quoting a component against one of its designations implies no approval by the maker and no claim of interchangeability.
Send the plate — both lines of it.
Photograph the type designation and the model or identification-code line, add the pumped liquid, the duty and the parts needed, and name the port. Seal, stack and coupling items are quoted as separate lines, so the ship can decide what to carry as spares.
