New bathroom and the bath tap runs cold

[BuggerFlip]

Hello,
I have recently had my bathroom refurbished. It was quite a big job in that the bathroom was gutted and everything replaced, bath location moved etc to accommodated a big walk in shower. It took a long 4 weeks by the 2 guys recommended by the bathroom shop. Overall I'm happy with their work but we kinda fell out slightly when I suggested they work longer days to finish the bathroom. This was the week before Christmas and the 2 1/2 week job was going into week 4. We couldn't put xmas tree up as lounge housed the bathroom suite and there was dust everywhere. For context the bathroom guys would turn up at 9.20 and work for an hour or so then go off for breakfast at 10.30 til 12 then finish at 3. There was no mention of their 4 hour day when they accepted the job. All I asked was that they try and get the work finished by the end of the week as kids were desperate to get xmas tree up and suggested they have breakfast before starting work for the day - that didn't go down too well!

Anyway, getting to the point. The bath was only used for the first time a couple of weeks ago and when running the hot tap only (through mixer spout thing) it runs hot then stone cold then hot for a bit then stone cold for a bit. It's almost impossible to run a bath of a decent temp. I've checked the boiler and it's running an error code of U9 which I believe just means the temp is 109. Before the bath refurb the bath hot water tap was fine and we had no issues at all. I contacted the plumbers reluctantly and was told it was a problem with my boiler. Would you agree it is their responsibility to ensure that the bath produces constant hot water or no? Having spent over £6k just for installation I'm quite upset that the bath isn't working as it should. There are no other issues with any other tap in the house or central heating from this combi boiler. Any advice on how I should tackle this with plumbers?

[Ridingthegravytrain]

If they won’t come out go to the bathroom shop and ask them about it. If it’s a mixer tap there could be an issue with the thermostat thing in it (I’m really technical )

If they recommended them I’m sure they can get them out if you cause a fuss. If that’s the only tap with an issue I don’t see how it can be the boiler?

[PigletJohn]

presumably you have a combi boiler. What make and model is it?

Run the bath hot tap into a bucket, time it to full, and calculate how many litres per minute you get. A photo of the tap, and the pipes and the pipes and connectors underneath, may be surprisingly informative.

Do the same with the kitchen sink hot tap.

And again with the kitchen sink cold tap.

You might find it works better if you run the hot and the cold separately, not together.

[BuggerFlip]

Thank you for your replies. Yes, it's a Worcester Bosch Greenstar 30Cdi. It's coming up to 12 years old. Not had any other issues though. The bath tap has a separate hot and cold handles (if that's what you call them) that come through one mixer tap. It's this one and is wall mounted. www.tapwarehouse.com/product/proflow-fusion-wm-bath-tap There's new flooring, underfloor heating etc and the bath is right up against the wall. Can't see how I can look at any pipes etc.

[PigletJohn]

you take off the bath panel, same as if you have to replace a tap or mend a leak. Some fitters like to pretend plumbing is immortal, and make the panels difficult to remove.

I can't see the performance figures for a 30CDi combi, but it can probably produce about 12 litres per minute of hot water. It might be that your bathtap is delivering less, or maybe the thermostat in the boiler is set too high and is overheating. So it will be useful to see your lpm tests.

It's also possible the flow sensor is not working right, but restricted flow is easier for you to check.

When you test lpm we will have an idea of if you have poor flow, or if you need to call out a boiler mender.

[BearPear]

We moved house last year and the stand-alone bath has a wall mounted mixer tap which gave an at best tepid bath. I had a chat with a plumber who suggested to only turn the hot tap a fraction. They are 1/4 turn taps which I only turn about 1/8 of a turn. Takes a while to fill the bath but at least it's really hot. Apparently it's something to do with there being wider pipes for a bath (compared with a kitchen sink for example) and the water travels too quickly through the boiler to be sufficiently heated.

[PigletJohn]

yes, that's typical of a combi. It's worse in winter when the incoming water from the main is colder and needs more energy to get it hot.

[Snowdrop18]

Isn't their work guaranteed even for a month, I mean at leat in the sense that they'll come out and look at it? Seems really crap for them to just assume it's the boiler.

[BuggerFlip]

Thanks everyone. I will do the test tomorrow (parents meeting this evening and tube disaster last night).

We too have a freestanding bath with wall mounted mixer taps BearPear (no bath panel PigletJohn and taps behind the tiles). I know what you mean about the turn so will definetly try the smaller turn and turn the thermostat down too. I have it up high as the water temp isn't great otherwise.

[BuggerFlip]

Just an update - turning the tap just a 1/8th did the trick. The bath runs constantly hot and the boiler doesn't show an error message. Thank you SO SO much BearPear. You saved me a whole lotta hassle!