Is Piglet John about? Boiler/bath issue still troublesome...

[LonelyandTiredandLow]

Hi,

I mentioned this a few weeks ago on another thread, but my bath is running lukewarm. The water seems to only be warming when I have the CH on. It's a combi boiler with underfloor heating downstairs. On a side note all of my green lights for that are flashing which I assume isn't quite right?

Anyho... the downstairs sink seems to run very hot, the tap for the sink where the boiler is is boiling hot, yet, on the same system, I've had to change my shower head to the thinner stream to make the water hot upstairs in my en suite (which dd and I have been using) and the bath runs lukewarm and no hotter.

If PJ is reading this - you advised to run the bath tap at half until it got hotter, which I tried. It didn't seem to get any hotter no matter how little water came out. The pressure isn't great (not sure but think it is worse than it was). Is there any other remedy?

I've turned the hot water dial up to max on the boiler. It started when I had a plumber over to fix a small leak on a pipe underneath the boiler that had caused a limescale build up that was dripping. He fixed that issue but we've not been able to have a bath since - that was in July! I've tried to get plumbers over three times since but haven't even had a call back, so I assume it is an easy fix that they can't be bothered to come out for?
TIA!

In case it matters, the boiler is a Worcester-Bosch

turn off the radiators using the wall stat and let them go cold.

Now turn on the bath tap at about half flow (about 5 litres per minute).

While it is running, go and feel all the radiator pipes (both ends). Have any of them started to warm up?

Use a thermometer to measure the temperature of the water coming from the cold taps. Then the hot taps. What is the difference?

How many litres per minute is the hot tap delivering while you do this?

The numbers will be different at the sink and the bath taps (which are bigger)

Post a photo of the bath tap please.

Literally no clue about boilers and whatnot so blind faith that you’re right (), @PigletJohn you’re amazing. I’m sure you’ll be modest about it, but it’s incredible how much help you’ve given on MN over the years. It’s very charitable.

Thank you @PigletJohn i'll get that done today and let you know.
As pp said, huge thanks and lots of

Back again @PigletJohn. I had the tap on for about 8 minutes and the radiators didn't get warm again. Here's a pic of the tap running and the top heat of 38C.

And that pic is full flow - but just on hot.

only 38C? Like a cat peeing on you?

How many litres per minute is it delivering? (fill a bucket and time it)

show me the tap please.

Yup, like a cat. I'll get the mop bucket up there shortly and time it.
The shower actually feels hot, which is what I don't understand.

OK it takes 2 mins 10 sec to fill the mop bucket and I noticed it starts hotter for about 5 seconds after the initial warm up then goes down to the 38 degrees. Here's a pic of the tap.

@PigletJohn

how many litres does the mop bucket hold?

@PigletJohn it's 12 litres.

the amount of warm water, and the temoerature rise, make me sspect the heat exchanger in the boiler. Your mixer is not a type likely to allow incoming cold to overwhelm the hot flow. Are you in a hard-watere area?,

it would be interesting to know the numbers from your sink hot tap.

the lights on your boiler can be decoded using the instruction book for your model.

if you find it difficult to get a local mender, see if the boiler manufacturer has a fixed-price repair scheme.

Hi @PigletJohn - sorry for the delay, I lost the thread!
Yes it is a hard water area - could that have caused a boiler issue?

The downstairs tap with the boiler in the room gets so hot it almost burns if you don't add cold. Sink in kitchen (about 8 meters away) is hot but not as hot as sink in the boiler room.

The flashing lights are for the underfloor heating - I do have the manual somewhere; was worried it could be linked.

I'll try contacting plumbers again now it's the weekend and mention the possible heat exchanger problem. If it is that, will it be an expensive job to replace/fix it?
again!