electric shower unit - dying?

[Mr-H]

The shower over my bath has started making an intermittent banging noise, and the water pressure momentarily reduces as it bangs. We live in a hard water area, and whilst I was showering this evening the flow reduced almost to nil and the water temperature increased dramatically. Is this an indication that the heater tank in the shower has become clogged with limescale? I believe there is nothing I can do about it if that is the case, so does this indicate the shower's life is coming to an end?

[The Builder]

When they start doing that, it's a bit scary. It can happen when there isn't enough water getting into the heating element. The little water that's in there overheats rapidly producing violent banging. A full service kit, if it's available, might fix it. Otherwise, if it's getting on a bit, probably cheaper and easier to buy a new shower.
If it is limescale, I guess the same applies... unless you can get a new tank relatively cheaply.

[alavahalf]

Another cause is the hose that links the shower unit to the handset is twisted or kinked internally. This will redude the flow, and the water overheats as TB stated.
Remove your handset and drop the hose into the bath and turn the shower on at it's coldest setting (this will increase the flow). Any rubbish or loose scale should flow out easily. If it does'nt try twisting the hose to see if the flow increases. If it does it may well be worth replacing your hose.