How long should my hot water actually stay hot

[Noxer]

Hello, Ive moved into a new place. I put my hot water on from the timer for 1 hour setting. about 1pm,
its now 2am in the morning. I feel the openvent pipe and its still hot, and it sounds like water rushing around.
The primarys are hot going to the cylinder and i got a 3port. So i check the boiler and press the hot water switch on and the boiler light comes on , so its calling when its suppose to be and going off when its suppose to be.

I just had the Old drayton programmer changed as the buttons on the old one was ****ed so engineer came and changed it. So maybe just maybe could of wired wrong? but i doubt it.

So is it just a good cylinder which can keep heated for 10 hours LOL

[fuzzy]

if primarys are hot and the boilers on when it should be off then yes there is something wrong