Hello helpful STW plumbers. The pressure release device on my electric shower has died. This is the third time in ~6 months this has happened. Last time I replaced the hose and the head as well as the PRD itself. The hose doesn’t have any weird kinks, we don’t tend to take it off the holder unless cleaning the bathroom., and we’re not in a hard water area, so I’m at a bit of a loss as to what’s causing pressure build ups.

Before I call a plumber and get it replaced has anyone got any other suggestions to try?

I repair a lot of showers. Actually, replace is a better term.
What make/model?
There seems to be no set routine for the PRV to pop. Families and little old ladies have the same problem. It is the water getting too hot/steam expansion inside the element that causes it.
The element is usually fine, so, either there isnt enough flow coming from the feed pipe, or, the outlet is choked too much for the showers liking.
Put the shower on its coldest setting,take the head off, see what the flow is like. It should be almost hosepipe like in its spray.There is a filter near the inlet. The usual advice is to clean the filter, though it is rare for it to get blocked.
New head/hose should clear any outlet problems, though you havent fitted one of those silly solid washers with a few tiny holes in it have you?
Thermostatic showers – usually new shower time if it has gone more than once. The thermostatic part is not doing its job, keeping the water too hot in the element, then blowing the PRV. It is a PCB change, possibly also the flow valve, so not economically viable to repair.
Where are you, I have some PRV’s here in Leicester, as well as a couple of good showers going cheap.

Thanks @alanl that’s exactly the sort of comprehensive answer I expect on STW!

It’s an electric one, a Triton Ivory 4. No idea how old the actual unit is (we’ve been in this house five years and it was there when we moved in).

Yeah it runs fine without the shower head. When I dismantled it all last night I did notice there was an almost solid washer with three small holes between the hose and the head. I assume that’s what you’re talking about…

We’re up in Leeds so probably a bit far!

Sounds like I should remove the offending silly solid washer (which I’ve done) and try it again with a new PRV!

Yes, they are the devils doing. I’ve been called to 2 houses that have these solid washers fitted, both were having problems, change the washer for a standard one, and all was fine.
If it is the tiny round Triton PRV, then I have one here, though it may be quicker to mail order it?
https://www.showerdoc.com/triton-prd-82800450

£7.69 for the tiny bit of rubber? You dont need the casing part, just swap the rubber. And they dont sell the rubber separately.

Marvellous, thanks for seeing me right! Will grab it from that link and save you the trouble of posting it. 🙂