In the last couple of weeks, my shower has cut out about half way through. I haven't touched anything, but suddenly there's a drop in the water pressure as if I'd turned it way down low, the pump stops (temporarily) and the water increases in temperature.

A few moments later, the pump kicks in again and I get full pressure to complete my shower. Sometimes it'll happen a couple of times before I complete a rinse.

The problem doesn't seem to occur with any of the other water uses - kitchen faucet, bathroom faucet, toilet tank, or even the washing machine.

Any idea what's causing the problem, why it occurred a short time ago, and what I might try to correct it?

Water Heater is a Sharp 3500 watt unit, about 4 1/2 years old.

I'd be looking at the filter gauzes as a first step, probably bunged up with carp causing the pressure to rise and switching off the pump.

First place to look is on the inlet side of your heater.

Okay. I'll take the hoses off and at least blow them out. I might have mentioned that when that pressure drops, there's a gurgling sound comes from the heater.

Edit: Learn something new all the time. I took that small hose off and discovered a very small concave screen filter right inside the opening to the heater. Finally managed to pull the rubber casing of it out and it does look as if there's some mineral build up in there. Soaking in vinegar for a few hours and I'll see if that helps tomorrow morning.

Wow! What a difference from such a small thing. That little screen almost hidden inside the heater at the water intake has slowly accumulated minerals over the years, unnoticed as it's been a slow process.

As mentioned, I pried it out yesterday and soaked in in vinegar, and gave it a bit of a scrubbing with an old toothbrush.

Water flow was immense this morning, more than I can remember. It was stinging!

Thanks, Crossy.