Wet End Replacement

There may come a time when you have to replace the Wet End on your pump. The Wet End may be installed either onto your existing pump or a new one. Either way you will need to remove your pump from your Spa, separate the Wet End from the Motor and re0install with a new Wet End.

With a few simple tools (see picture) and this help sheet to guide you through the process, you will be able to successfully replace your Wet End.

Removing The Pump From Your Spa

  1. Start by isolating the electrics and turning off the power at the RCD. Once you have gained access to the equipment area you must now unplug the power lead connected to the electrical control box. This may be a 'JJ' Plug or an AMP type plug. (see picture).

  2. Close any vales (if fitted) or drain your Spa.

  3. Disconnect the two waterpipes connected to your Wet End and screws holding your waterpump down. You can now remove the pump from your Spa and work on it in a convenient place.

Wet End Disassembly / Removal Of Old Existing Wet End

  1. Now the pump is in a comfortable place to work on you can start by removing the front cover of the Wet End and the Phillips screws retaining it (see picture).

  2. Now the screws have been removed, the cover will have to be levered out due to the 'O' ring inside sealing the body and cover. Take a small flat bladed screwdriver and prise the front cover apart in equal measures around the body. As you are going to replace the Wet End you don't have to stand on ceremony with this operation (see picture).  
    You are now ready to remove the impellor.

  3. You will find that there are three easy ways to remove your impellor which will depend on your motor/pump combination. You will have to lock the pump shaft in order to rotate the impellor off it in an anti-clockwise direction and remove it.
    The following are the three ways:

    1. Insert a flat bladed screwdriver through the small hole in the fan casing at the end of the motor and locate it in the shaft screwdriver slot. Holding firmly (you may need a second pair of hands), rotate the impellor ant-clockwise and withdraw (see picture).

    2. As above except that you will have to remove the motor fan casing to insert the correct size screwdriver (see picture).

    3. With a pair of suitably sized molegrips clamp the exposed motor shaft between the motor and Wet End and rotate the impellor anti-clockwise direction and remove. A second pair of hands may be helpful with a 
      stubborn impellor (see picture). This operation is not always possible due to Wet End type/design.

  4. You can now finally detach the Wet End from the Motor body. There are two ways that this can be done, depending upon the make of motor/wet end combination. Either way it is straight forward. The options are:

    1. Take a 7mm spanner and undo the 4 hexagon bolts holding the Wet End onto the Motor Body (see picture).


    2. You may have a Motor where the Wet End is retained by long bolts that run through the motor body. Start    by undoing the screw that retains the Motor cowel at the back and remove  (see picture). Unscrew the 4 long bolts that retain the Wet End, pulling them back just 2 or 3 inches. You do not have to take them out (see picture).

    Your old Wet End back plate can now be removed from the Motor (see picture)..

    You are now in a position where you can re-install your new Wet End. This is just a reversal of the procedures that you have just followed except that you will have to disassemble your new Wet End. You have already done this on the old one but do take more care this time as you don’t want to damage the new parts.

New Wet End Disassembly

  1. Undo the Phillips screws holding the front plate onto the Wet End body. Do not use a drill or an electrical screwdriver as you can damage the Wet End very easily. The impellor and top hat are inside. (see picture).

  2. Now that the screws have been removed, the cover will have to be levered out due to the ‘o’ ring inside sealing the body and cover. Take a small flat bladed screwdriver and prise the front cover apart in equal measures around the body. Take care not to damage the sealing surfaces or the ‘o’ ring (see picture).   There is a wear ring inside which looks like a top hat. Note which way round it is for future assembly (use a sketch of photo) (see picture). 

Wet End Assembly

  1. Locate the impellor inside the backplate housing.
    Some Wet Ends have what is known as a ‘slinger’, a little top hat which slides over the impellor shaft when installed into the housing. The large diameter will point towards the impellor. Slide this onto the impellor shaft. (see picture).

  2.  Re-assemble the back plate onto the motor, taking care not to damage the seal, either with the 4 hexagon bolts or the long bolts through the motor body Tighten opposite screws evenly(see picture).

  3. Rotate the impellor onto the motor shaft, winding hand-tight in a clock-wise direction as you look at it. You will need to lock the motor shaft for you to get enough purchase. (see Wet End Disassembly Section-3 above for locking the motor shaft).

  4. Re-fit the motor cowl if required

  5. Replace the wear ring, (large top hat) noting which way round it goes.

  6. With a smear of grease around the large ‘o’ ring in the front face plate, press firmly the faceplate into the backplate

  7. Insert the screws around the faceplate and tighten opposite screws evenly with a 
    Phillips hand screwdriver. (Do not use an electrical screwdriver or drill as you can  
     very easily crack the housing around the screw hole lugs).(see picture).

Re-Install Your Pump With The New Wet End

Important:   Do Not Run Your Pump Dry – Risk of Overheating the Motor

  1. With your pump back in the Spa, re-position and connect the two water pipes back onto the pump.

  2. Tighten down the pump mounting screws making sure you have replaced any shims that may have been under the motor feet.

  3. Plug-in the motor power lead into your Spa control box.

  4. Resist replacing any covers or trims around your Spa at this point as you may need to re-tighten the water pipe unions.

  5. Open the gate valves if you have them and re-fill your Spa.  Check for leaks, re-tighten if necessary.

  6. Turn on your Spa, check for leaks

  7. Replace covers and trims - and relax!

“Congratulations you have successfully replaced your Wet End”