This question is regarding Watermill Pump WASP 50 - Spare Parts

Noise and temperature variation Wasp 50

I have an elderly (7 years old) Wasp 50. Recently the temperature fluctuates to colder and sound from the pump changes at the same time. This either rights itself within minutes or is corrected by turning the shower control off and back on. The hot and cold feeds are gravity of equal head. The pump ends and flexible hoses have been dismantled and no dirt of foreign object found but originally the input hoses were bent beyond the recommended 45 degrees max. I suspected collapsing of the hot feed due to the bend, heat and age. I have re aligned the feeds to eliminate the bends but the problem still exists. Do you agree with my diagnosis and recommend new flexible hoses or is there another known cause of this problem? Many thanks for your help.
Asked 8 years ago by Rod
From your description of the fault it sounds like you have air getting into the pump, could you have a partial air lock?

I don't think that you will have a problem with the hoses you should be able to look down them and see if they have collapsed internally ,

Answered 8 years ago by Anonymous

Thanks for your advice a couple of weeks ago. I checked thoroughly for airlocks and found none, flow was good in both hot and cold pipes.

Therefore I ordered a new set of flexible hoses and fitted them. This has cured the problem so I can but assume the input hose probably on the hot feed was collapsing due to the depression (suck) on that hose.
There was no blockage or visible problem in the removed hoses or filters.


Answered 8 years ago by Rod Sleigh

View Spares and Order Parts:

Do you need any additional help to find the correct spare part?

Please click the following link if you would like to see other answers or ask a question regarding the Watermill Pump WASP 50 - Spare Parts

If you've landed here and this question is not about your specific product, please take a look at these similar items on our Grundfos Shower Pumps Spares page. Alternatively, if you're looking for any other brands you should view our full range of Shower Spares.

If you do not want to proceed with a repair or you want to buy this item or similar, please consider one of our Replacement Grundfos Shower Pumps

For any other support request please get in touch.