Saunier Duval Bulb and Capillary Aquastat SD 123 C - Ref. 05291600
Bulb and capillary thermostat Saunier Duval SD 123 C - Ref. 05291600 is a manometer that measures and controls the pressure or temperature of the boiler circuit. When it fails, it can cause incorrect readings, which may lead to the boiler locking due to a false lack of pressure or poor temperature regulation. This component is compatible with boilers from the Themis, Thelia, and SD ranges, such as the Themis 223, Thelia 623, and SD 135 models, among others. A technician must confirm through diagnosis whether it needs to be replaced when you observe issues with pressure or temperature readings.
- Type of part
- Pressure gauges & aquastats
- Status
- Refurbished
- Catalogue reference
- 05291600
- Warranty
- 1 year
Saunier Duval boilers compatible with reference 05291600
Pressure gauge with reference 05291600. Three confirmed compatibilities: Themis 223 and Thelia 623.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval Themis 223 | Themis | Contrasted |
| Saunier Duval Thelia 623 | Thelia | Contrasted |
| Saunier Duval SD 135 | SD | 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 ref. 05291600 is the part for your boiler
The part reference, model, and equipment revision must be verified against the manufacturer's documentation.
- Find the reference printed on the installed part and check whether it matches the catalogue reference 05291600. 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 that require diagnosis on the manometer 05291600
The manometer shows the pressure of the boiler circuit. These are the typical symptoms and what to do:
Common symptoms and faults
- 01
The boiler stops or locks when the water has been hot for a while, even though the thermostat is set correctly.
Cause: The aquastat cuts the electrical circuit because its bulb detects a temperature it considers excessive.
Measure the actual water temperature with a thermometer at that moment to rule out a real overheating before replacing the part.
- 02
The boiler never reaches the temperature you set; it falls short.
Cause: the bulb sends a higher reading than the actual one and the aquastat cuts the circuit prematurely
Check that the bulb is properly inserted into its sheath and in contact, not loose or dry.
- 03
The boiler does not start or locks erratically, and the capillary tube appears bent or crushed in some section.
Cause: A damaged capillary loses the internal fluid and stops transmitting a reliable temperature reading.
Inspect the entire length of the capillary for sharp bends, crushing, or breaks before discarding the part.
- 04
The water keeps heating continuously until the boiler's safety mechanism is triggered.
Cause: The internal contacts of the aquastat have stuck and do not break the circuit when the temperature rises.
With the boiler disconnected, use a multimeter to check if the contact opens and closes as the bulb temperature changes with hot water.
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.
Saunier Duval 05291600 pressure gauge datasheet
- Catalogue reference
- 05291600
- Uniclima internal SKU
- ABCSD223C
- Brand
- Saunier Duval
- Type of part
- Pressure gauges & aquastats
- Units in stock
- 7 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- Delivery time shown at checkout
- Return
- 14 days
Frequently asked questions about the pressure gauge 05291600
Is this bulb and capillary aquastat compatible with the Thelia 623 boiler?
When should the bulb and capillary aquastat of the Themis 223 be replaced?
Spare parts related to Saunier Duval Themis
