Roca Laura boiler: exploded view, spare parts, and technical data

The Roca Laura range is still very much present in homes and small businesses, even though it has been discontinued. Its presence in older installations turns every breakdown, every inspection, and every search for a part into a very specific matter: knowing exactly which model is on the wall and which component needs replacing.

In these units, the difference between a quick repair and a long intervention usually comes down to a simple but decisive piece of information: the exact model and spare part reference. The Laura family includes wall-mounted combi boilers, sealed models, and versions with micro-storage or storage, and that changes both the behavior and the compatible parts.

If you have a problem with your boiler, you can use our free error code search tool. From there, you will be able to find and solve all errors easily and effectively.

A range that is still very much alive in real installations

Roca Laura belongs to that generation of boilers that are no longer seen in showrooms, but are still working quietly behind many kitchens, utility rooms, and technical rooms. Its disappearance from the catalog did not erase its footprint in the installed stock, which is why interest in its internal diagrams, references, and spare parts remains high among installers and maintenance technicians.

The family was designed as a compact wall-mounted solution, intended to provide heating and domestic hot water in a single unit. That combination, common today, already then offered a practical answer for households that wanted a discreet appliance with good performance and a reduced physical footprint. In practice, its compact format helped it fit into spaces where a floor-standing boiler would not fit or would have been unreasonable.

Its current value lies not in novelty, but in usefulness. When an appliance keeps working after years of service, the issue is no longer the technology itself but the traceability of the spare part. That is where the Laura range remains of interest: parts are still available, and there is still enough technical documentation to identify many of its main components.

How the Laura 35 family is organized

The Laura 35 series consists of wall-mounted combi boilers, meaning units capable of supplying heating and DHW production. Within this family, there are models with different approaches: the F models work by micro-storage and the AF models by storage. The difference is not decorative, but functional: it changes hot water response and the recommended usage profile.

The F models were designed for low or medium DHW demand and offer notable comfort for intermittent use. Micro-storage provides a small reserve that improves hot water delivery without turning the system into a large tank. For that reason, they are suitable for homes with moderate usage habits or with moderate demand peaks.

The AF models, on the other hand, are aimed at more intensive use. Their storage-based logic allows them to respond better when more taps are open, more bathrooms are used at the same time, or when there is a sustained need for hot water. That orientation makes them more interesting in large homes or in installations where consumption is not concentrated in a single point.

There is another shared feature that defines the range: sealed technology. The combustion chamber remains hermetically closed, which improves safety and allows installation in indoor spaces with limited direct ventilation, always within the applicable regulatory requirements. In practical terms, this design better isolated the combustion process from the environment where the user lives.

Dimensions, output, and operating limits

The Roca Laura 35 measures 53.5 cm wide, 85 cm high, and 39.2 cm deep. These figures help explain why it fit so well into home renovations and replacements of previous appliances. It is not a tiny boiler, but it is a compact unit for the output it provides.

On the thermal side, the range declares a heat output of 30,000 kcal/h, with a minimum useful output of 9.26 kW and a maximum reaching 34.72 kW in the Laura 35/35 and Laura 35 A versions, and 35 kW in the Laura 35/35 F and AF variants. These figures help explain the real operating range of the unit, which is very important when reviewing performance, oversizing, or replacing it with another boiler.

Installation also depends on clear hydraulic parameters. The maximum heating pressure is 3 bar, with a safety valve also set to 3 bar. In DHW, the maximum pressure reaches 7 bar. Filling is between 1 and 1.5 bar, and the expansion vessel is 12 liters. These are figures worth keeping in mind because, when symptoms such as leaks, pressure fluctuations, or safety valve discharges appear, the source of the problem is not always the most visible part.

The range also operates with heating temperatures between 30 °C and 85 °C, and DHW temperatures between 30 °C and 60 °C. That range provides enough room for adjustment in conventional domestic installations and explains why the electronic control board had the ability to modulate flame output according to the demand at the time.

Models, fuels, and compatibility

The series was sold in versions for natural gas and LPG or propane. The reference documentation features four very representative references: Laura 35/35 F and Laura 35/35 AF, plus their natural gas and propane versions. That distinction is not minor, because the exact reference determines valves, burner, adjustment, and the correct spare part.

In terms of efficiency, these boilers were sealed combustion units with good performance for their time, and precisely for that reason they remained useful in many installations for years. Replacement by later series such as Novamax within the BaxiRoca universe does not erase the fact that many Laura units are still operational and require occasional technical attention.

An important aspect for maintenance is that the Laura 35 range was not intended to be combined with solar energy using the same schemes as other families. In that integration, the Laura 20 range did offer a more suitable alternative with a specific hydraulic connection kit. This detail helps avoid confusion when comparing units with similar names but different behavior.

The interior most often consulted: hydraulics, combustion, and safety

The exploded view of the Laura clearly shows that the heart of the unit is not a single part, but a highly coordinated set of hydraulic, thermal, and control elements. In the water circuit there are the heating return, mains inlet, DHW outlet, heating flow, heat exchanger, circulation pump, expansion vessel, pressure gauge, and three-way valve. Each performs a specific function and, when it fails, it alters the overall balance of the system.

The heat exchanger, with reference 122230080 in the documentation consulted, is one of the most sensitive parts because it transfers energy between circuits and is subjected to constant thermal load. If it becomes dirty, degrades, or loses efficiency, the user may notice irregular hot water, unusual temperature rises, or less stable heating operation. The circulation pump, code 122270010, is another critical point: without that hydraulic push, the heat is not distributed as it should be.

The circuit safety elements include the safety valve 122450080, the heating pressure switch 122460020, and the overtemperature safety system. These components do not work to provide comfort, but to prevent the unit from going out of range. When one of them trips, it is not ruining the boiler out of whim; it is warning of an out-of-limits condition.

The combustion section includes the burner, ionization probe, ignition electrodes, combustion chamber, flue restrictor, extractor, and the sealed box in the versions that include it. In practice, these parts explain why the same symptom can have different origins: ignition failure does not always point to a single cause, and the control system needs to verify flame, air, gas, and exhaust at the same time.

The electronic board and wiring that coordinate everything

The electronic board is the part that turns a boiler into a system governed by logic rather than just pressure or flame. In the Laura 35, the most cited manufacturer code is 122420630. This component receives signals, orders ignitions, monitors sensors, and decides when to increase or reduce output. It is, in a sense, the appliance’s small brain.

Its practical importance is enormous because a faulty board can mimic faults in other areas. An ignition error can seem like a gas, probe, or ventilation issue when in fact the problem lies in electronic management. The opposite can also happen: a bad hydraulic part can make it seem as though the board has failed. That is why diagnosis in this range requires an orderly reading of the whole system.

The electrical wiring, the 3.15 A fuse, the ignition transformer, and the possible connection to a room thermostat complete the architecture. They are not eye-catching parts, but they are decisive. A badly connected wire or a blown fuse can stop an entire boiler with an apparently trivial issue. In units of this type, electricity travels like a network of fine nerves; if one is cut, the body responds in silence.

The reference 122420630 remains especially sought after because electronics are among the parts most sensitive to the passage of time. Capacitors age, contacts wear, and solder joints can lose reliability after repeated heat cycles. That is why, when spare part documentation mentions this board, the information is relevant both to professionals and to users who need to identify the exact cause of a shutdown.

The spare parts most often identified by name and reference

Among the most commonly consulted components are the flow meter 122280010, the expansion vessel 122151990 or the 12-liter version, the analog pressure gauge 122152600, and the ionization probe and electrode kit 122255010. These are parts closely linked to visible symptoms: no flow reading, pressure losses, abnormal pressure readings, or lack of flame detection.

The modulating gas valve 122450240, the natural gas manifold, the extractor 122220290, and the variable-signal pressure switch 122460020 also frequently appear. In a sealed boiler, the coordination between gas and exhaust is inseparable. If combustion does not stabilize or the fan does not generate the proper signal, the appliance must not continue operating.

The value of these references lies not only in the number, but in the way they organize the repair. When a technician sees a part code, the fog lifts. It is no longer a generic Laura, but a specific pump, a specific air vent, or a specific probe. That shift speeds up the job and avoids wrong purchases, which in a discontinued boiler can be costly in both time lost and unnecessary returns.

Accessories, templates, and flue exhaust

The Laura 35 range also had very specific installation accessories, and these remain useful when working on already installed units. Among the hydraulic connection elements are mounting templates with fittings and the spacer frame. The documentation includes references such as 140040094 for the PMI-LAURA 35 template with fittings, 140040093 for the PMA-LAURA 35 template with fittings, and 140040223 for the spacer frame.

These accessories do not always draw attention, but they are what make a clean, aligned, and verifiable installation possible. A well-designed mounting template leaves the correct distances, organizes connections, and simplifies later replacements. In boilers of this type, that foresight is worth almost as much as a spare part, because a properly installed unit ages better and is diagnosed with less uncertainty.

For exhaust, the range had specific kits for vertical outlet, twin simple outlet, and 80/125 outlet, with different references depending on fuel and version. This part is sensitive because flue exhaust is not a decorative accessory, but a requirement for safe operation. When an old boiler is replaced, the exhaust system must respect the design for which the appliance was conceived, or performance and safety suffer.

There were also extractor hood disconnection kits for atmospheric boilers related to Laura 30 and Laura 35. That detail illustrates well the technological transition of the era: adapting installations to new safety conditions and new combustion criteria was one of the changes that marked the evolution of domestic boilers in Spain.

Why technical documentation is still so sought after

Information about the Laura is of interest because a model becoming obsolete does not eliminate its real service life. As long as an installation is operational, someone will have to bleed, replace, verify, or adjust it. And at that point, the exploded diagram documentation works like a map: it lets you know what is behind each cover, what each assembly is called, and which reference corresponds to the correct part.

In addition, the Laura 35 range is a classic case of discontinuation with an still-active spare parts market. That places it in a very particular middle ground. It is not a current sales product, but it is not a dead memory either. It lives through repairs, which is why technical tables, manufacturer codes, and exact naming still have economic and operational value.

From a maintenance perspective, boilers of this type teach a very practical lesson: it is not enough to know that the appliance is a Laura. You need to distinguish whether it is 35/35 F, 35 AF, natural gas or propane, and check exactly which element is needed. The difference between a probe, a gas valve, or an electronic board is not a minor detail; it is the boundary between a solved breakdown and a prolonged intervention.

The ongoing relevance of a discontinued boiler in day-to-day maintenance

Roca Laura remains relevant because it is still part of the daily routine of many technicians and users. The gradual replacement by more modern models has not erased its physical presence, and while it continues operating in homes built years ago, it will keep generating questions about parts, dimensions, and compatibility. That permanence explains why a well-organized exploded view is worth as much as a sales sheet.

The best way to deal with a boiler in this family is with calm precision: identify the model, check the fuel variant, review the operating pressure, locate the affected component, and do not assume that an apparent fault always has the same origin. In an installation of this kind, details matter. A reference number, a specific probe, or a properly named pressure switch can save hours of work.

Over time, the Laura has become an example of how a technical unit survives beyond its commercial cycle. It no longer sets trends, but it remains useful, legible, and repairable. And in domestic heating, that combination still has very tangible value: stable heat, orderly diagnosis, and spare parts that still allow the installation’s life to be extended.