20 – Retrofit New Water Pump

For all Westomatic machines with a High Pressure Brewer

Downloadable PDF Version of this Bulletin – 20 – Retro Fit New Water Pump

Retrofit Water Pump

On our High Pressure Brewers (HPB), we have introduced a new water pump.The original water pump we used has been made unavailable by the supplier.We believe this new water pump will also increase reliability of the HPB.

It is essential you feel comfortable decommissioning and removing the HPB from the machine – if not, we have a technical support team/support videos available that will guide you through the process.

You will need some equipment to complete this job:


1 x Small Crosshead Screwdriver
1 x Large Crosshead Screwdriver
1 x Small Flathead
10mm Spanner
13mm Spanner
Wire Strippers

1 x Complete High Pressure Pump Kit with regulator fitted
1 x 6mm John Guest Fitting for Espresso Boiler (tube pre-fitted)
2 x Faston Terminals

Replacing the Water Pump

1. Decommission HPB – this step requires specialist knowledge – please reach out if you need help. It MUST BE DONE before the HPB can be removed. There is an Emergency Decommission procedure if the pump has been removed already – see our technical support page.

2. Carefully remove the HPB brewer from the machine

3. Remove the 2 nuts at the top of the HPB that hold the brewer to the support bracket. Be careful not to pull the brewer out. The HPB will be attached to machine by a safety chain – this needs unscrewing. The HPB also has a water pipe, a main drain and the overflow pipe. These all need to be removed from the bottom support bracket.

Once these are removed the brewer can be carefully lifted up and out of the machine, and placed on a level surface to refit the water pump. 

4. Both side panels on the HPB need to be removed. There are 4 screws that hold each one in place – a large crosshead screwdriver will be required. Ensure you carefully remove the Earth terminal from the side panel. 

5. Next the old water pump needs to be disconnected and removed. 

  1. Remove the power to the pump using a small crosshead screwdriver
  2. Unclip the pump from the springs on the side
  3. There are 2 silicone tubes attached – one at the top of the pump and one at the bottom, these both need to be removed. 
  4. Lastly the John Guest fitting from the nylon pip to the boiler needs to be removed – push up the green clip and remove

6. In the kit we have supplied a new pump with all the connectors and tubes attached. We have also supplied a new 6mm John Guest fitting for the espresso boiler (pre-fitted with the correct length tube).

Now the old pump has been removed completely – including silicone pipes…

  • Remove the T-Piece from the boiler pipe.
  • Using a 10mm Spanner remove the 6mm self-forming fitting from the boiler. (It will feel stiff to remove this part).
  • Fit the new 6mm John Guest Fitting for the espresso boiler into the boiler and tighten using a 13mm spanner. Ensure this fits very tight to create an effective seal.
  • Thread the T-Piece through the cut out in the base of the housing -this will help with fitting the new parts.
  • Fit the complete new pump kit – the pipe fits into the T-Piece, and the T- T-Piece is then fitted to the pipe on the boiler fitting.

7. Next we fit the new pump into the HPB

  • Connect the pump to existing bracket/springs.
  • The shorter length of silicone attaches to the base of the pump (the non-pressure side).
  • The longer length of silicone attaches to the pressure regulator. The pump can pump up to 15 Bar – the pressure regulator opens up if it exceeds 14 Bar – maintaining pressure.
  • You should be left with the old pump + elbow + pipe, and also the old 6mm boiler fitting.

Rewire power connector

1. On the power cable for the original water pump (removed in the early stages) – locate the connector. 

  • Using a small flathead screwdriver unclip the cover
  • Using the small crosshead remove the wire connectors from the block
  • Also remove all the plastic connectors as shown in the below image -these can be recycled.

2. With these parts removed the 3 wires should now be clearly visible – Earth(yellow+green), Live (brown) and Neutral (blue). You may need to strip some of the covering back to have enough usable wire.

  • The earth wire is no longer used – this can be taped back to the covering out of the way/or cut off.
  • Supplied in the kit are 2 x 6.3mm Faston terminals.
  • Using the crimping section of the wire strippers – locate the red dot!
  • Place terminal in position on wire strippers, and insert the wire into the end – crimp down hard to attach to the wire. Repeat for both Neutral and Live.
  • The terminals can now be replaced on the new water pump. As shown in the image below. Blue then Brown as shown.

Complete Setup

3. Complete a final check of all the fittings to ensure they are fitted correctly.

  • Silicone pipe to base (non-pressure end) of water pump.
  • Longer length of Silicone pipe to pressure regulator – no kinks.
  • New 6mm John Guest fitting on the boiler – securely fitted to boiler. Faston Terminals attached securely- Blue then BrownWater Pump clipped to side of HPB

The next stage is to reassemble the HPB

  • Replace the EARTH terminal on the inside of the side panel, then reattach both side panels with 4 x screws on each side
  • Ensure you carefully fit the HPB back into the machine, ensuring the safety chain is reattached, the pipes are refitted and the main drain located into the support. Lastly reattach the HPB to the bracket with the nuts.
  • Now the boiler must be RECOMMISSIONED. There are tutorial videos on commissioning the HPB on the We:Support section of the WVS website or support via the technical call line.

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