Saunier Duval Thema C23 / F23 Control PCB - Ref. ST1407 CA04003

Saunier Duval boilers compatible with reference 05727900

PCB with reference 05727900. Two confirmed compatibilities: C 23 and F 23.

Proven compatibility

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 ref. 05727900 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.

1. Find the reference printed on the installed part and check whether it matches the catalogue reference 05727900. If it is not visible, do not identify the part from its shape alone.
2. Check the full boiler model on its data plate and look for it in the model associations on this page.
3. Compare the connections and physical body with the original part before installation.
4. If anything is unclear, send us a photo of the marking via WhatsApp before placing your order.

Symptoms and faults that the PCB 05727900 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 temperature controls of the boiler do nothing: you raise or lower them and the behavior of the burner does not change.

  Cause: The control board does not correctly receive the commands from the controls, so it cannot modulate the flame.

  Before replacing it, check that the physical controls turn normally and are not broken or loose inside.

• 02

  The boiler does not respond to the room thermostat: it stays on all the time or does not start even when the thermostat requests it.

  Cause: The control board does not receive the signal from the thermostat, so it cannot decide whether to start the burner.

  Bridge the two thermostat wires directly in the boiler terminal block to see if it starts; if it starts this way, the problem is with the thermostat or the wiring.

• 03

  Some pilot light or LED on the boiler is flashing in a strange pattern, or stays on in red, without any noticeable gas or water fault.

  Cause: A fault in the electronics of the PCB can cause the LEDs to display a code that is not related to the rest of the installation.

  Note the exact pattern of the blinking (number of flashes, color) and compare it with the fault code table in the manual.

• 04

  The domestic hot water and heating are conflicting with each other: it heats what it shouldn't or takes too long to switch from one service to another.

  Cause: The control board is not properly managing the priority of the circuits, which is causing conflicts between them.

  Make sure to check that the demand for domestic hot water (turning on a hot water tap) is really noticeable before assuming that the fault is with the PCB.

Fault codes from Saunier Duval that this spare part resolves.

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 05727900 PCB.

Catalogue reference

05727900

Brand

Saunier Duval

Type of part

PCBs (control boards)

Units in stock

1 unit

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

ST1407 CA04003

Marking of switch SW1

TY-F1D 94V-0

Manuals and technical documentation

Official documentation of the boiler, useful for locating the part and cross-referencing the fault codes.

• Saunier Duval F 23 manual (PDF)Document © Saunier Duval, provided as a technical reference.