Siemens fridge water filters
Siemens American style fridges are built on the same BSH platform as Bosch and take the identical UltraClarity filter. If you own a Siemens fridge, the Bosch UltraClarity page on this site applies to you as well.
How to identify your Siemens fridge
Siemens prints the full appliance model number, starting with a letter such as K, on a rating plate inside the fridge compartment, usually on the side wall.
The UltraClarity cartridge sits in a dedicated internal housing shared with sister brand Bosch; if your Siemens fridge has no such housing, it may use an external filter on the water line instead and this page does not apply to it.
Water filters for Siemens fridges
Each reference below has its own page on this site with the full list of fridges it fits, the fitting steps and the mistakes that send people back to buy a second cartridge.
| Filter reference | Fitting position | Change interval |
|---|---|---|
| 644845 (UltraClarity) | Internal cartridge, UltraClarity housing system | Every 6 months |
Where Siemens owners go wrong
- Searching only under the Siemens name and missing that the identical cartridge is sold under the Bosch UltraClarity listing, which can be easier to find in some UK shops.
- Not checking that your specific Siemens range actually has an internal filter housing before ordering, since not every Siemens fridge sold in the UK is fitted with one.
When to change the filter
Siemens recommends a cartridge change roughly every six months, in line with the wider UltraClarity platform used across Bosch and Siemens fridges.
Siemens water filters: common questions
Does the Bosch UltraClarity cartridge fit my Siemens fridge?
Yes. Bosch and Siemens fridges share the same parent company, BSH, and the same UltraClarity filter platform, so the reference on this site's model page applies to both brands.
Tools, access space and water quantities to plan for
Replacing an internal Siemens fridge cartridge is a small job, but it is easier if the shelf space and the water flushing are planned before the old cartridge is removed.
- Allow 10 to 15 minutes for the physical change, plus 5 to 10 minutes to flush water through the dispenser.
- Clear an area about 300 mm wide and 250 mm deep in front of the filter housing so your hand can turn the cartridge without hitting jars, bottles or the shelf edge.
- Keep one dry cloth inside the fridge and one cloth on the floor below the door. A normal change may release a few teaspoons of water, but a badly seated cartridge can release more.
- Use a jug or bowl of at least 1 litre for the first flushes. Smaller glasses make the job slower and increase spills.
- Have a marker pen ready and write the fitting month on the visible end of the new cartridge, or on a small label near the housing.
The fridge does not normally need to be moved for an internal cartridge change. Do not pull the appliance out unless you are working on an external water line or checking the shut off valve behind the fridge.
Step by step fitting procedure
Start with the water dispenser not in use and the ice maker not actively filling. If your appliance has a dispenser lock, use it while you are handling the cartridge. This avoids an accidental water call while the filter is out.
Open the fridge door fully and remove any food blocking the filter housing. Put a cloth directly under the housing. Hold the old cartridge firmly, then rotate it in the release direction until it stops. Pull it out in a straight line. Do not bend the cartridge downwards while it is still engaged, because that can load the plastic head of the housing.
Check the old cartridge as it comes out. If an O ring or small seal appears damaged or left behind, stop and inspect the housing before fitting the new cartridge. A seal trapped in the wrong place is a common reason for dripping after the change.
Insert the new cartridge squarely into the housing. Push until it is fully seated, then rotate it to the locked position. The movement should be firm, not forced. If it stops after only a small turn, remove it and start again, because the bayonet lugs may not be aligned.
After fitting, close the fridge door and dispense water into a jug. Use short fills of 500 ml to 1 litre, then pause for a few seconds. A practical first flush is 3 to 5 litres, or until the flow is steady and any air spurting has stopped. Discard this water. If your fridge has an ice maker, discard the first batch of ice after the filter change.
If the appliance has a filter reset function, reset the indicator only after water has been flushed. If you need general fault checks after a change, see the fridge water filter FAQ.
Figures to check during and after the change
| Check point | Normal figure | What it tells you |
|---|---|---|
| Time to remove and refit the cartridge | About 2 to 5 minutes once access is clear | Longer usually means the housing is hard to reach or the cartridge is not lined up squarely. |
| Initial flushing volume | About 3 to 5 litres | This clears trapped air and loose carbon fines from a new carbon filter. |
| Water flow after flushing | Steady stream, no repeated bursts of air | Bursts after several litres suggest air is still in the line or the cartridge is not fully locked. |
| Leak check period | First 10 minutes, then again after 1 hour | Slow leaks may not show during the first glass of water. |
| Change record | Month and year written at fitting | This avoids relying only on memory or on an indicator that may not have been reset. |
Frequent faults, recovery steps and special cases
If no water comes through after the change, first confirm that the dispenser lock is off and that the door switch is being made when the door is closed. Then remove the cartridge and refit it, keeping it level with the housing. A cartridge that is not fully turned into the locked position can block flow.
If water drips inside the fridge, dry the housing and check again with a torch after dispensing 500 ml. If the leak is at the joint between the cartridge and the head, remove and refit the cartridge once. Do not use tools to tighten it. If the housing itself is cracked, stop using the dispenser until the appliance has been inspected.
If the dispenser flow is weak immediately after fitting, flush in several short runs rather than holding the paddle continuously for several minutes. This lets air move out of the internal pipework. If the flow was already weak before the filter change, the cause may be low supply pressure, a partly closed water valve, a kinked feed tube or a frozen section in the fridge water path, not the new cartridge.
If the old cartridge will not turn by hand, empty the shelf area and dry the cartridge surface so your grip does not slip. Apply steady hand pressure only. Pliers can deform the cartridge end and can also damage the housing. If it still does not move, the safer route is to stop and arrange service rather than breaking the internal head.
Special cases need a different check. A Siemens fridge without an internal filter housing may have an external inline filter fitted behind the appliance or under the sink. In that case, the internal cartridge procedure does not apply. A plumbed fridge that has been unused for several weeks should be flushed for longer than a routine change, often 5 litres or more, because stagnant water may be sitting in the line. More general troubleshooting points are covered in the FAQ.
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