Expansion Vessel Euroline ZW24-1E Ref. 8705407005

Junkers boilers compatible with reference 8705407005

Expansion vessel with reference 8705407005. 15 verified compatibilities: Euroline ZW23-1 AE23 and Euroline ZW23-1 AE31.

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 ref. 8705407005 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 8705407005. 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 expansion vessel 8705407005 resolves.

The expansion vessel absorbs the expansion of water when heated. These are the typical symptoms and what to do:

Common symptoms and faults

• 01

  When the heating starts, the pressure gauge rises quickly and sometimes triggers the safety valve.

  Cause: The vessel does not absorb the expansion of the water when heated because it has lost the air chamber or the membrane is broken, which causes overpressure in the circuit.

  With the boiler cold and the circuit without water pressure, press the valve of the expansion vessel: if no air comes out forcefully or water comes out, the membrane is broken.

• 02

  The circuit needs to be filled every few days because the pressure keeps dropping.

  Cause: A tank that does not adequately cushion the variations in water volume forces the system to constantly compensate with the filling valve.

  First, check the radiators, bleed valves, and safety group for any visible leaks before assuming it is the expansion vessel.

• 03

  The tank weighs more than normal, and when you knock on it with your knuckles, it doesn't sound hollow anywhere.

  Cause: This indicates that the membrane has ruptured and the vessel has filled with water instead of maintaining the air chamber.

  Tap the glass from top to bottom: if it sounds equally solid across the entire surface, it is flooded.

• 04

  The boiler indicates a pressure problem and locks out, although the pressure gauge appears normal when cold.

  Cause: An unbalanced vessel allows the pressure to fluctuate too much when heating, and the control unit shuts down for safety in response to those sudden spikes.

  Note the cold pressure and check it again just as you start the heating; if it spikes within a few minutes, suspect the expansion vessel.

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 expansion vessel Junkers 8705407005

Catalogue reference

8705407005

Brand

Junkers

Type of part

Expansion vessels

Units in stock

1 unit

Status

Refurbished

Warranty

1 year

Shipping

1-2 business days

Return

14 days

Manuals and technical documentation

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

• Junkers Euroline ZW23-1 KE31 manual (PDF)Document © Junkers, provided as a technical reference.