only small amount of hot water Baxi Instant 105e

Hi
I'm so sorry if this has been asked before. I did a bit of a search but came up with nothing exactly like this.
When I turn on a hot tap I get the store of nice hot water.
The boiler IS firing up, I have replaced the diverter valve diaphragm previously when it wasn't firing up. It was working fine for a while.
The thing is, even though the boiler is firing up the stream of water goes warm then cool after the initial preheated store.
The radiators aren't getting hot when I run the DHW so no worries there, again a problem I have fixed before.
The CH is working fine.
The boiler does lose pressure but then it always has! I have replaced the PRV previously too. I've been so disappointed with this thing! The installer is not around anymore it would seem. I have to keep topping up the pressure but the DHW problem persists regardless of the current pressure.
I hope that is all the info you need to suggest something.
Thanks very much
Terry

compared to a normal 105e the instant is a pile of sh#te.
If the tap demand light is illuminating on boiler when you turn on tap then i would suggest cleaning the plate heat exchanger and probably changing the hw sensor which is by the plate.

Northants what was your installers initials , a certain guy fitted hundreds of these in the county

Thanks for the reply, and telling it how it is!
I wondered at first if I was just unlucky with a dodgy one but it does seem they are just rubbish!
Anyway, I will try those suggestions and see how I get on.
To be fair, the installer KA was fantastic and did extra work for nothing, it's just the boiler that let me down

Well I first replaced the temp sensor and nothing changed.
I then struggled massively to get the plate heat exchanger out, there was just no space to get it out. I ended up taking the cold water feed and the whole inlet manifold off just to get the thing out! I'm certain this shouldn't be the case so god knows why mine wouldn't come out anywhere.

Anyway, I cleaned it until no more gunge or dirt came out and it ran clear.
Refitted and lo and behold, the problem still persists. I still just get the preheat store and then it runs cold even though the boiler is firing.

So... any more clues please?
Cheers
Terry

Have you changed the D.H.W Differential ?

Could well be a gas pressure problem so you should get a gas safe registered boiler repair person to look at it.

Baxmax said:

Have you changed the D.H.W Differential ?

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No, I haven't. I did change the diaphragm a while back and it's not been long since I had the differential valve off and cleaned it up. I mistakenly thought the boiler wouldn't fire up if that wasn't working properly as that's the problem I had once before...

mrgas said:

Could well be a gas pressure problem so you should get a gas safe registered boiler repair person to look at it.

Click to expand...

Well it's due a service which I guess involves shutting the gas off anyway so I may as well bite the bullet...