Bath tap hot water not heating

[BobbyJoe]

Hi everyone,

I had my gas combi boiler serviced last month and the engineer completed the job, filled out the paperwork and said it was in good shape as it is just over 2 years old.
Today I ran the hot water tap in the bathtub and it was lukewarm (36 degrees Celsius), I checked the kitchen and basin hot water taps and they were hot 47 to 52 Degrees C.

I checked the boiler dials and the pressure wasn't dropping when running hot water, I looked at the pipes in case of leaks and couldn't see anything, the water from the bath tap was flowing as normal not dripping or weak yet the temperature was not as hot as it has been.
I turned up the DHW to full and once again all other taps were delivering hot water yet the bath tap was luke warm.

Any idea what the issue could be as a few months ago it was hot but not now, I would be grateful for any information.

Should I turn the boiler off or reset it, it might not do anything but I have no idea why the bath tap is not hot anymore, thank you.

 

[townfanjon]

Slow the bath tap down and see what happens

 

[BobbyJoe]

Hi thank you I gave that a try and still no difference. I also turned the boiler off for a bit to see if it would help reset it but unfortunately the water is at 36 DC.

 

[EvilDrPorkChop]

Are you in a new house? There's probably a mixing valve under the bath.

 

[BobbyJoe]

Hi thank you for the replies, I am not in a new build and the hot water in all taps was fine last weekend however it maybe something else. Around 2 months ago the lead on the roof of the building was leaking it was a leak just under the gutters and it just happened to be fixed this week and this is the week the hot water in the bath cooled down as last weekend it was fine.

I live in a top floor flat and all the pipe works go up into the attic which only the factor has access to, so I am going to contact the factor to ask what the issue was as it may be something to do with it or it may be nothing. What I am baffled about is it's only the hot bath tap that is affected, I will contact my factor and see what they say before I call a plumber as I am baffled by it and somewhat annoyed as I require hot baths to treat certain conditions.

 

[BobbyJoe]

Update: So this morning I tried the bath hot water tap and opened it less than half way (slowing it down more than usual) and then temperature was then 47.5 DC, where as yesterday it was 36.5 DC fully opened.
The question I have is what would cause this issue and do I need to replace the tap or other?

Throughout the flat the water flow for both hot and cold taps is fine no issues there all are mains fed, the mixer taps, bathroom, copper/pipe works and gas combi boiler are all around 2.3 years old as I replaced everything when I got the flat. Boiler was serviced in October.

I have never had any issues with the hot water tap for the bath and this week is the first time, I would be thankful for any advice or information thanks. 😀

 

[ShaunCorbs]

Colder incoming mains this time of year and full flow baths taps always cause an issue / complaint