Shower pump playing up

[SIDD]

I have a water pump underneath the bathtub which kicks in whenever I open the hot water faucet for shower. The issue is that if I keep the showerhead in the holder at top (so it hangs there and I don't have to hold the shower head) it does not start. I have to take the showerhead out and lower it a bit towards the ground, the pump kicks in. Once the pump has started, then I can put it back at the top and it stays fine. Its just when starting the hot water I need to do the above mentioned process.

It is a bit of a nuisance doing it everytime. It would help me a lot if you can tell me if this issue can be solved easily or would I need professional help and how do I go about doing it.

Thanks in advance

 

[picasso]

Do you know the make and model of the shower pump and if its negative head or not ?

 

[SIDD]

Do you know the make and model of the shower pump and if its negative head or not ?

Sorry I dont, Its underneath the bathtub and the side panel is sealed with silicone. But if needed I can pry that open.

 

[picasso]

It could be something simple slowing the flow like limescale on the shower head, try taking the head off and see if the shower pump starts.