Ideal c30 shower problem

[Bob1410]

System is an Ideal C30 combi
Have had an issue lately when having a shower.
Sometimes there seems to be an audible noise in system then shower hot water pressure drops so there is hardly any water coming out of shower head.
Any idea as to what the problem is?
Thanks

 

[MeldrewsMate]

Does the water 'pressure' drop elsewhere in the house at the same time?
When does the 'pressure' recover?

 

[Bob1410]

Will try running another tap elsewhere
I can get pressure back by twisting shower control back and forth between cold and hot

 

[Deleted member 267285]

Check the shower hose.

 

[Madrab]

Sounds like the thermostatic valve is shutting down, anti scald may be kicking in. What kind of shower is it? /are you in a hot water area? If the shower isn't getting too hot then it may mean the thermostatic valve/filters need looked at.