Saunier Duval Isomax F35 H PCB Ref. 0020048284
Control PCB for Saunier Duval boilers from the Isomax and Isotwin ranges, reference 0020048284. It incorporates a NEC microcontroller uPD78F0538 and a voltage regulator STMicroelectronics L7805CZT, with silkscreened connectors for the hydraulic module (X2) and the outdoor temperature sensor or accumulator sensor (X41). It is replaced when the electronic control of the boiler fails.
VAT included
Consult via WhatsAppSaunier Duval boilers compatible with reference 0020048284
PCB with reference 0020048284. Three confirmed compatibilities: Isomax F 35 H-MOD and Isotwin C 25 E.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval Isomax F 35 H-MOD | Isomax | Contrasted |
| Saunier Duval Isotwin C 25 E | Isotwin | Contrasted |
| Saunier Duval Isotwin C 30 E | Isotwin | Contrasted |
Can't see your model or have questions? The printed reference takes precedence. How to check it · Send us a photo via WhatsApp.
How to check if the reference 0020048284 is the part for your boiler
What determines it is not the boiler model, but the reference printed on the part you already have installed.
- Find the reference printed on the installed part and check whether it matches the catalogue reference 0020048284. If it is not visible, do not identify the part from its shape alone.
- Check the full boiler model on its data plate and look for it in the model associations on this page.
- Compare the connections and physical body with the original part before installation.
- If anything is unclear, send us a photo of the marking via WhatsApp before placing your order.
Symptoms and faults that the PCB 0020048284 resolves.
The PCB controls the ignition, modulation, and safety features of the boiler. These are the typical symptoms and what to do:
Common symptoms and faults
- 01
The boiler works but does not recognize the hydraulic module nor does it change its behavior when it should.
Cause: The connector of the hydraulic module is housed in the PCB; if it fails, the boiler does not receive its information even if the module is functioning properly.
Check that the connector of the hydraulic module is properly seated and without bent pins before replacing the PCB.
- 02
The external sensor or the accumulator sensor gives readings that don't make sense, or the boiler acts as if it is not connected.
Cause: The input from that sensor is processed on the PCB; a fault at that stage can simulate a faulty sensor even if the sensor is fine.
Disconnect the sensor and measure its resistance directly with a multimeter to rule out that the fault is in the sensor before replacing the PCB.
- 03
The boiler heats up more than usual on the inside and sometimes stops for no apparent reason.
Cause: A voltage regulator on the PCB that overheats can cause intermittent protection cuts.
Check if the fault occurs mainly after several hours of continuous operation, indicating that it may be a thermal issue.
- 04
The display freezes or stops responding even though the boiler remains on.
Cause: A microcontroller lockup on the PCB can cause the display to freeze while the rest of the system continues to operate normally.
Turn off and on the boiler from the main switch and check if the display responds normally again.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| 13 | Main PCB fault. | Fault in the main PCB or its connections causes loss of control/readings. Check power supply and wiring harness, connections with the panel/interface; if it persists, test or replace the PCB. |
| 20 | Communication/compatibility fault between user interface and main circuit (software/coding). | After replacement or misalignment, the PCB and the display do not share the product code or protocol; the PCB locks the equipment. Verify product and bus coding (MMI/eBUS), check wiring, and if not corrected by reprogramming, replace the PCB or interface. |
These symptoms can have more than one cause. If your boiler displays a fault code, send it to us via WhatsApp along with a photo of the labeling, and we'll tell you if this is the part.
Data sheet for the Saunier Duval PCB 0020048284
- Catalogue reference
- 0020048284
- Brand
- Saunier Duval
- Type of part
- PCBs (control boards)
- Units in stock
- 4 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- 1-2 business days
- Return
- 14 days
Data read on the part and in the manufacturer's documentation
What we have not been able to verify does not appear here.
- PCB code
- 0020048284
- Batch / manufacturing date
- 94S40041 G0181.94
- Microcontroller
- NEC uPD78F0538 (78K0 family, currently Renesas Electronics)
- Voltage regulator
- STMicroelectronics L7805CZT
Manuals and technical documentation
Official documentation of the boiler, useful for locating the part and cross-referencing the fault codes.
- Saunier Duval Isomax F 35 H-MOD Manual (PDF)Document © Saunier Duval, provided as a technical reference.
Frequently asked questions about the PCB 0020048284
Does this PCB 0020048284 work for an Isomax F35H-MOD?
What microcontroller does the PCB of the Isomax F35 H have?
What is the reference to order this PCB for the Isotwin C 30?
What are the X2 and X41 connectors on this PCB used for?
What voltage regulator is used in the PCB of the Isomax F35 H?
Spare parts related to Saunier Duval Isotwin
