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Blog · Sourcing guide · 2026-07-24

Marine boiler spare parts — a sourcing guide for Aalborg, Miura, Kangrim, Alfa Laval, Mitsubishi and Osaka

Commercial vessels use auxiliary oil-fired boilers as well as exhaust-gas boilers and economisers. For their spare parts, safety-valve set pressure, gauge-glass rating, burner-atomiser identity and refractory specification can affect operation and applicable class requirements. The oil-fired boiler and the exhaust-gas boiler fail differently, and that decides the parts list. An oil-fired boiler wears where the flame is: atomiser, diffuser, electrodes, refractory. An economiser has no flame and no burner, and fouls instead — at low engine load its tubes run cool enough to hold acid in the soot, so it corrodes and fouls together. A soot fire is prevented rather than fought: circulation running whenever the main engine turns, the gas side washed and blown, the temperature difference watched. This guide covers frequently encountered OEM families, the data needed to identify each component and the choice between an OEM route and a documented alternative. It does not quote lead times or prices — those depend on the specific unit, vessel schedule and confirmed supply route.

Which OEM families are common on commercial vessels

Several OEM families recur across marine boiler installations. Identify the family, then the exact unit: a tube, gasket or refractory line is read against that unit's drawing, and a bought-in burner or the gas side of a composite boiler brings a second plate into the request.

  • Alfa Laval (formerly Aalborg Industries) — Mission OL, OS and OC series auxiliary and composite boilers, plus Aalborg exhaust-gas economisers. The OL is now sold as Aalborg OL, formerly MISSION OL, and older plates may still carry the MISSION name; the Aalborg OL parts page covers its membrane-wall furnace and burner variants.
  • Miura — GK series vertical water-tube composite boilers and HB, VWH and VWK series auxiliary boilers; the Miura boiler parts page explains the figure groups and suffixes these plates carry. Where a unit is of once-through design it holds little water for the steam it makes, and scale from poor feed shows as tube metal temperature before it shows on a gauge.
  • Kangrim Heavy Industries — MB, MD, MH, MS and PC series auxiliary and composite boilers, and EA/EB/EM economisers, on Korean-built vessels. A composite boiler carries both heating surfaces in one shell, so it has two populations of parts, fired side and exhaust-gas side. Say which side the work is on; the Kangrim boiler parts page sets out what each series letter names.
  • Mitsubishi Heavy Industries (MHI) — auxiliary boilers on Japanese-built vessels, including the MC and MJC series, which MHI lists as dual-firing auxiliary boilers marketed through Mitsubishi Heavy Industries Marine Machinery & Equipment.
  • Osaka Boiler Manufacturing — auxiliary boilers, including the vertical OVS series for mid-size tankers.
  • Saacke — burner systems used across many OEM boiler platforms, including the SKVJG-M and ROTONOX rotary atomiser burners and DDZ pressure-atomising burners for higher capacities. Saacke also builds its own fired (FMB) and combination (CMB) marine boilers, so a Saacke plate may belong to the boiler, the burner or both.

What we need to identify the correct boiler unit

Boilers are one of the equipment categories where component identity depends on both the boiler OEM and the burner OEM — those are often different companies. Send the following with the RFQ:

  1. Boiler nameplate photo — with maker, the model designation exactly as stamped, including any figure group or suffix after the series letters (e.g. an Aalborg OL that may still read MISSION OL, a Miura GK, a Kangrim MD or PC), serial number, design pressure and steam capacity.
  2. Burner nameplate photo — separate plate, often on a different housing. Saacke, Weishaupt, Oilon, Volcano or the boiler OEM's own burner (Alfa Laval KBSD, KBO).
  3. Component identity — burner gun, atomiser, nozzle, ignition electrode, photocell / flame sensor, safety valve, gauge glass, blowdown valve, level probe. Tubes belong on that list too, and a tube is not identified by its length: what matters is the material specification, the outside diameter and wall thickness, the bank it sits in, and whether the ends are expanded or welded.
  4. Service parameters — design pressure (bar), design temperature (°C), steam capacity (kg/h or t/h), fuel type (MGO, HFO, LSMGO, dual-fuel), and current operating pressure if different from design. Add the water treatment the boiler has been run on. Chemistry decides what is found when the drum is opened — hard scale, soft sludge, pitting under deposit — and that is the difference between ordering gaskets and ordering tubes.
  5. Class society and last survey — DNV, LR, ABS, BV, ClassNK, RINA. For safety valves and gauge glasses this determines the certificate requirement. It also separates two kinds of item. Gauge glasses, packing and gaskets are consumables the crew renews. A safety valve or a low-water cut-out is a survey item: tested, recorded and accepted against the approved arrangement, so it has to match that arrangement and not merely fit.

Burner components — atomiser and nozzle identity is the RFQ challenge

Burner atomisers, nozzles and burner guns recur in boiler RFQs. A mismatched atomiser flow rate can alter burner performance, an incorrect nozzle angle can damage refractory, and an unsuitable burner-gun length can affect flame stability. A burner that will not light and one that lights and then trips are two different parts lists, so say which you have. Nothing igniting points at the ignition side: electrodes, cable and transformer, the ignition fuel solenoid, a blocked atomiser. A flame that establishes and drops out points at flame sensing and atomising: a sooted or aged cell, a worn nozzle, oil too cold for the atomiser. Quote the lockout code as well. Send the following:

  • Atomiser flow rate — stamped on the atomiser body (e.g. "60 GPH 45°B", "200 kg/h 60°S"). The flow rate and the spray angle (measured in degrees) both matter.
  • Atomiser type — pressure jet, steam-assisted, mechanical, spinning cup (rotary cup burners on some Saacke and Volcano platforms).
  • Nozzle size and thread — Danfoss Oil Nozzles are stamped with GPH and spray angle. Aftermarket alternatives (Delavan, Fluidics, Steinen) exist but the flow tolerance differs.
  • Ignition electrode gap and length — specific to the burner OEM.
  • Photocell / flame sensor model — Honeywell, Siemens, Danfoss, Kromschröder, or the burner OEM's own.

Safety valves and gauge glasses — documentation is the identity anchor

Certification requirements for safety valves and gauge glasses must be checked against the vessel documentation and the applicable class rules. At RFQ time, the existing certificate is an important identity reference. Send the following:

  • Set pressure — stamped on the valve body (e.g. "7.5 bar", "15 bar"). This is not the design pressure of the boiler. The valve is set on a rig and sealed, and the seal is the evidence it still sits where it was set. Adjusting it aboard is not a field job: the spring is supplied against a pressure range rather than a single figure, and a valve reset or resprung is certified again.
  • Nominal size and flange rating — DN25 / DN40 / DN50 / DN65, PN16 / PN25 / PN40.
  • Valve maker — Bopp & Reuther, Sempell, LESER, Crosby (Emerson), Kunkle, Yoshitake, or the boiler OEM's own component.
  • Required documentation — for a complete valve, spring or nozzle, confirm the acceptable certificate and supply route against the technical file and class requirements. A surveyor expects the seal intact, the certificate to hand, the stamped setting to agree with the approved figure, and the easing gear to work.
  • Gauge glass — reflex or transparent, working pressure, size (length × width × thickness), and the mica-shield specification for high-pressure service.

Feed water pumps and control

Boiler feed-water pumps are typically small vertical multistage centrifugal units (Grundfos CR, Wilo Multivert, KSB Movitec) or horizontal single-stage pumps. Identification follows the general pump identity pattern. Boiler-specific context includes water treatment and low-flow protection: where a minimum-flow bypass or Yarway / Sarco valve is fitted, confirm the orifice or valve specification against the installation documentation and applicable class requirements. Water level is three separate things, and an enquiry that treats them as one gets the wrong part. The gauge glass is the direct reading, with its glasses, packing and cocks, all consumables. The transmitter or electrode column is the control element: it starts and stops the feed pump and raises the alarms, and it drifts as probes scale up. The low-water cut-out is neither — it shuts the burner down independently of the control and is tested and recorded as a protective device.

Refractory bricks and insulation

Refractory linings in oil-fired auxiliary boilers are inspected and renewed according to condition, the maintenance plan and survey requirements. Refractory and gaskets are specified against the boiler, not against a measurement: a brick of the same size is not the same brick if alumina content and service temperature differ, and a shaped piece in the throat or quarl is made to that boiler's opening. Manhole gaskets go the same way. Check the furnace construction before ordering brick: on a membrane-wall boiler such as the Aalborg OL, Alfa Laval reduces refractory to a protective layer at the bottom of the furnace, so a side-wall or roof brick list for that boiler points to the wrong drawing. Send the following for a refractory RFQ:

  • Boiler OEM and model.
  • Refractory zone — burner throat, quarl, side wall, roof, floor. Each zone has a different material specification.
  • Material grade — high-alumina castable, ceramic fibre board, insulating firebrick (IFB) with the specific alumina content and service temperature.
  • Quantities per zone — often given by the OEM in a spare-part list or drawing.

OEM route vs verified alternative

For burner nozzles, atomisers, gauge glasses and refractory components, a documented alternative may be considered when material, dimensions, warranty conditions and class requirements allow it. For safety valves, burner guns and OEM-specific assemblies, the acceptable route must be confirmed from the installation documentation because certification, alignment, ignition geometry and sensor wiring can be unit-specific. Vessel Core records the proposed route for each RFQ line.

What we cannot promise before the RFQ is reviewed

Vessel Core does not quote boiler spare-part prices, lead times or supply route before the specific unit, application, class context and identification data are confirmed. Every quotation is prepared for the specific request. A quotation for a safety valve or gauge glass remains preliminary until the applicable documentation requirement is known.

How to send the RFQ

Use the RFQ form. Attach clear photos of both the boiler and burner nameplates, including their complete model and serial information. Use the RFQ evidence checklist to review the fields item by item.

Frequently asked questions

What are the common marine boiler OEM families?

Alfa Laval (Aalborg Mission OL, OS, OC series), Miura (GK, HB, VWH, VWK), Kangrim (MB, MD, MH, MS, PC, plus EA/EB/EM economisers), Mitsubishi Heavy Industries, Osaka Boiler Manufacturing (OVS series), and Saacke for burner systems used across many OEM boiler platforms.

Why do boiler RFQs need two nameplate photos?

The boiler OEM and the burner OEM are often different companies. Alfa Laval Aalborg boilers can carry Alfa Laval's own burners, such as the KBSD pressure-atomising burner named for the Aalborg OL, or third-party burners, and Saacke builds both boilers and burners. A boiler RFQ for a burner component needs the burner nameplate, not just the boiler nameplate.

What class-society context matters for boiler safety valves?

Documentation requirements for safety valves and gauge glasses can differ between DNV, LR, ABS, BV, ClassNK and RINA. Before replacing a complete valve, spring or nozzle, confirm the required certification and component acceptability against the vessel documents and the applicable class rules.

What identity evidence does a burner atomiser need?

Send the atomiser flow rate stamped on the body (e.g. "60 GPH 45°B", "200 kg/h 60°S"), spray angle, atomiser type (pressure jet, steam-assisted, mechanical or rotary cup), and nozzle size and thread. A mismatch can affect burner performance and the requirements recorded for the installation.

Are aftermarket boiler refractory bricks safe?

For side walls, roofs and floors, a documented alternative may be considered when alumina content, service temperature, dimensions and installation requirements match. For the burner throat and quarl, follow the approved material specification because thermal-shock duty is more severe.

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