Before you start
This is the pump-internals repair demonstrated in the video, not a universal diagnosis for every low-flow fault. Pump removal and refitting involve mains wiring.
Before you work
Unplug at the outlet and prevent reconnection before internal work. The front-panel power button does not isolate the machine.
Allow the machine to cool and release stored pressure by the correct service procedure before opening any boiler connection.
Mains wiring and electrical safety checks belong to a suitably qualified repairer. Refit all protective parts before a powered check.
Tools and supplies
Model-appropriate drivers for pump access
Calipers for checking the ball and seal dimensions
Matched EPDM seal and any other verified pump wear parts
A record of wiring, hose routing and small-part order
This guide follows the correction in the current video description rather than silently repeating the spoken seal size. It does not reproduce the live mains measurements or exposed variable-AC bench test.
Part 1 of 3
Assess and prepare
01
Confirm that pre-infusion is the failing stage
The source example delivers no water during pre-infusion, then begins flowing when full pump power arrives. Record whether your symptom has the same pattern.
A general lack of pressure, a blocked water path or no delivery at all requires broader diagnosis. Do not assume every low-flow symptom is this internal seal.
View this section in the original video0:16 Reference: Video 0:16 · Guide checks
The front-panel and group-flow example at the start of the pre-infusion video. 0:30 in the video Part 2 of 3
Workshop walkthrough
02
Isolate and remove the pump for bench work
Unplug, cool and establish safe pressure conditions before access. Photograph and identify wiring, hose routes and the pump mounting before removal.
The access montage moves the electrical enclosure aside and removes the pump. Follow the verified procedure for the actual model rather than guessing from the sped-up views.
View this section in the original video2:06 Reference: Video 2:06 · Guide checks
03
Open the disconnected pump and preserve the order
Open the removed, disconnected pump as demonstrated. Lay the small internal parts out in order while withdrawing the piston and spring assembly.
Keep the ball and seal from being lost; they are small and easy to miss during cleaning.
View this section in the original video4:37 Reference: Video 4:37 · Guide checks
04
Match the seal to the actual pump revision
Inspect the worn seal that the video identifies as a common cause of failed pre-infusion. Replace it with a verified match for the pump variant.
Use the corrected description when sourcing: it specifies a 1.8 or 1.9 mm cross-section, 9 mm outside-diameter EPDM seal; it separately notes some pre-2022 ULKA EFM pumps use 1.5 mm cross-section × 5 mm inside diameter.
The spoken 2 mm cross-section × 4 mm internal-diameter specification differs from the current description. Do not use it as one universal size. Confirm the actual seal and pump before ordering.
View this section in the original video5:28 Reference: Video 5:28 · Guide checks
05
Inspect the pump ball as a separate wear item
The source checks the small ball with calipers and compares it with a badly worn example. The stated nominal diameter is about 4 mm for the demonstrated pump.
Keep a serviceable ball only when it matches the correct specification and condition for that pump. Overall pressure loss may involve this part even when pre-infusion still works.
This is a component check from the example pump, not a pressure-test pass certificate.
View this section in the original video5:53 Reference: Video 5:53 · Guide checks
06
Reassemble the pump and restore its connections
Reassemble the matched parts in their recorded order and refit the pump using the original mounting and hose routes.
Restore all documented wiring and protective parts. A qualified repairer must check the electrical work and leaks before the machine is returned to use.
View this section in the original video6:25 Reference: Video 6:25 · Guide checks
Part 3 of 3
Finish and verify
07
Check pre-infusion with the machine closed
With the machine fully reassembled, compare the pre-infusion flow with the original symptom and confirm normal delivery afterwards.
The source also discusses temporarily increasing pre-infusion strength. That changes operation; it does not repair worn pump internals.
View this section in the original video7:24 Reference: Video 7:24 · Guide checks
The archive’s final pre-infusion demonstration still has the casing open. The written functional check requires full reassembly. 7:50 in the video The original workshop film
Watch the repair in context
The original film includes live voltage measurements and a powered bench rig. Those are technician demonstrations, not instructions in this written workflow.
Final checks
Use this checklist to review the work and the evidence. It does not claim that these checks were completed on your machine.
The pump variant and corrected seal size have been verified.
The ball, seal and internal assembly are complete and correctly ordered.
Hoses, electrical connections, mounting and covers are restored.
Closed-machine pre-infusion and normal flow are checked; leaks and electrical safety are signed off.
Sources and model notes
Written from the original BrevTech footage and its current description. Every screenshot links to the matching video time. The film may omit service detail; model and procedure limits are stated above.
Use the procedure and parts that match the actual machine. Stop if the fault, connections or required safety checks cannot be established. Read the BrevTech repair disclaimer .
