Weird hot water issue

[Riley]

Scratching my head a bit with this one. I don’t know if anybody has come across this before. Bath in a property has very basic nonceramic taps when she runs h & c, hot runs cold after about 10 mins. It’s off a combi boiler sonoy a lack of water. When she run just the hot tap it runs continuously hot.

Hope somebody might be able to offer a pearl

 

[Riley]

Ha ha it’s a valid point and may well be worth I try. It just seemed so odd that tap runs for 10-15 mins then goes Stone cold

 

[Riley]

its not new build is it?

No mate

 

[peter0504030201]

is your boiler pressure gauge set higher than 1.5 bar , The system may be slightly over-pressured , the increase in temperature results in an increase in pressure, this might push it over its limit and again it will cut-out ?

 

[Riley]

The boiler doesn’t cut our

 

[Gasmk1]

then if all else is ok it must be the bath taps. can you put your temp sensor on the hot flow from the boiler and watch that

 

[Riley]

then if all else is ok it must be the bath taps. can you put your temp sensor on the hot flow from the boiler and watch that

I completely agree with you from what I can tell the boiler works perfectly albeit is the Biasi

 

[fixitflav]

Yeah and the boiler continues to fire. It’s almost as if the hot water is diverting elsewhere but it’s not

The heat must be going somewhere. Are you sure the rads aren't getting hot (whether you want them to or not) when the hot runs cold? Might be problem with the 3-port valve in the boiler. I would switch it to hot water only mode and see if it happens, and if the boiler continues to fire if it does.
My son has a combi (Vaillant if I remember right) which was behaving oddly, not unlike your symptoms. They said it was an uncommon but known fault, and replaced the valve under warranty. Been OK since.

 

[Riley]

I went back last week the radiators are categorically not getting hot. I have quoted for new taps

 

[fixitflav]

I went back last week the radiators are categorically not getting hot. I have quoted for new taps

Sounds like you have discovered a new law of thermodynamics

 

[townfanjon]

I went back last week the radiators are categorically not getting hot. I have quoted for new taps

I wake up in the middle of the night thinking about this one, make sure you report back lol
If its the taps I will show my arse on the townhall steps.

 

[Harvest Fields]

I wake up in the middle of the night thinking about this one, make sure you report back lol
If its the taps I will show my arse on the townhall steps.

Make sure you get a photo

 

[townfanjon]

Make sure you get a photo

I will do a selfie with the mayor eh

 

[Riley]

Sounds like you have discovered a new law of thermodynamics

Ha ha perhaps I have, the only thing changed there is the taps, from speaking to the last tenant there was never a problem since they’ve put these ones on with a much greater flow there has been a problem. There’s no other logic to it unfortunately

 

[Riley]

I wake up in the middle of the night thinking about this one, make sure you report back lol
If its the taps I will show my arse on the townhall steps.

I’m glad it tortures your brain like it does mine

 

[fixitflav]

I’m glad it tortures your brain like it does mine

I still think the 3-port valve is the most likely culprit.