Water in the shower doesn't get as hot as before

[CatAndHisKit]

....and doesn't stay hot for long as previously. It's a mains shower on a pump, relatively new (5-6yrs), Mira. The pump is not the best one from memory as I was trying to save money when installing. It's a good strong pump and pressure still as usual. I don't know if pump and thermostat are linked?

Anyway, hot water stayed hot for hours after the hot water cylinder heated up - now it's about 2 hrs, and apart from that, the hot shower lasts less time as it never gets as hot as before .

When on max temperature it's not scorching like it used to be, so need to turn it up to max very soon after starting and that increases the water flow which means a shorter shower time.

Can this be repaired or does it mean the pump is a goner (they did tell me pumps need to be changed every few years).

Btw hot water in taps is very hot as before.

We had similar and it was caused by a leaky valve in the shower, allowing water to flow back into the boiler. It was a quick, easy fix. Hopefully yours will be something simple like that - get a plumber to check it out before assuming the worst
Ps - When the pump started to go on our old shower we definitely knew about it as it got noisier and noisier!

thanks you, Amazing. I did wonder if this was aplumber's thing or I'd need a bolier engineer in case it's some commection.

This is likely down to two things. It sounds like the mixer cartridge on your shower is not reading the temperature correctly and is then mixing the water incorrectly. This can sometimes be fixed by recalibration, but if the shower is over 5 years old, it is very likely you will need a new thermostatic cartridge. Depending on the make of the shower, you can probably just order a new one from their website and if you feel confident enough, they are relatively easy to replace.
If you are running out of hot water from your cylinder, then this is likely to be down to your cylinder thermostat not reading the temperature properly. It may have just come lose and need reseating, or it may have also broken and need replacing. There are a few things you can check yourself before calling someone out to deal with it. If it is an unvented cylinder (runs on mains) then look up the manual and it will tell you where your thermostats are on the cylinder, check that they are sitting correctly in their pockets and the retaining screw is holding it in correctly. If it is an vented cylinder (runs from water tank in the loft), then you will likely have a rectangular thermostat about a quarter to a third of the way up the tank normally held in place by a wire coil. Check that it is sitting in the polystyrene insulation directly against the copper tank. On both thermostats, you should also hear a click when you move them from hot to cold and vice versa. If that doesn't help, then definitely call out a heating engineer, who should be able to do the shower for you too

Muchly, as I mentioned, the hot water in taps is not affected, it's hte opposite actually - so when the shower runs out of hot water, the tap water is still very hot. It used to be more simultaneous - so I'd think it's not to do with the cylinder, or can it still be?
Cartilage sounds more of a possibility. But if it's not an exopensive job (as could be also the valve as orevious poster said) I'd rather plumber changed it, I'm not hands-on with these things.

Sorry, misunderstood. Thought you meant that you were running out of hot water on the taps too. If you are unsure of anything, it is always a better idea to get someone else in to do the job. If you do know the manufacturer of your shower, check the price of the part on their website, your plumber may be able to get it cheaper and it should then be a chargeable hour to replace the cartridge.

is cartridge and valve the same thing, Muchly?

I am quite sure it's just the shower - but was asking on here as I thought it was to do with pump, thankfully it sounds like a lesser issue so I'm glad I've asked.

Pretty much. It's a part of the valve. It is what mixes the water, so that you get the correct temperature from your shower head. Over time, what can happen, is that it can get furred up with limescale and this causes it to read the temperature incorrectly. Sometimes, just the cartridge itself breaks down and reads the temperature incorrectly. It is normally an easy job, as long as you can isolate the water to the shower and know the make of your shower. If it is just a cheap £80-£100 shower, it is more cost effective to replace the whole shower

thanks, Muchly. It's Mira, wasn't as cheap.