Electric instant units die on the element and the high-limit thermostat. Gas instant units die on ignition packs and water-flow diaphragms. Both hate hard twin-city water. We descale where it is honest to do so; a pinholed exchanger is a replace.
We check earthing on electric instants. An unearthed 3kW unit in a DHA bathroom is not a job we will energise.
If you wanted a storage geyser instead, see the electric storage and installation pages — we will say which fits the bath better than a 7-litre instant trying to fill a tub.
Questions we get on this job
Gas or electric — do I need to know?
Look at the hose. A gas pipe means gas. A thick flex means electric. Send a photo if unsure.
Why does it trip the breaker?
Usually element or wiring. We megger and check the point — see also electrical.
Can you install a new instant on the same fittings?
Often. We still leak-test gas and check the electrical load.
Scale every year?
In this water, yes, if you run it daily. A service before December is cheaper than a winter emergency.