Thermostatic Shower lukewarm

DJ123

Hi

I have recently had a new worcester bosch combi boiler fitted, along with a new mixer tap shower (Bristan Artisan AR2 THBSM C Thermostatic Bath Shower Mixer Tap.) This was all installed by a heating engineer. The problem that I am having is that the water coming out of the shower is lukewarm, and I am unable to make it any hotter. I did some reading of the instructions, and it explains how you can reset the maximum temperature by removing the handle that controls the temperature and then turning the valve spindle underneath it towards hot or cold. I did this, and I had an awesome hot shower afterwards! Each shower I have had since then has got progressively colder until I am back where I started (after about 3 or 4 showers I would say) . The valve spindle will not turn any further in the hot direction now, and I am not sure what else to do. I have measured the water temperature, and it is 37 degrees on the hottest setting. The shower says that it should be 38 degrees, with the option of going hotter than that if you press the override button (which I have done). 

My boiler has temperature settings for the water, and I have tried 50, 55, 60, and 65, and they all result in the same lukewarm shower temperature. The other taps in the house reflect what I have set the water temperature to be on the boiler, so I don't believe it is the boiler, and I think the shower is somehow limiting the temperature of the water. I have checked the pipes leading to the shower mixer (hot on the left as I look at it), and the hot side is blazing hot. The water pressure is really good too. I have tried varying the water flow whilst in the shower, and it doesn't make any difference.

At this point I'm really not sure what to do. I guess I should be getting in touch with the heating engineers who fitted it, but I'm trying my best to avoid having to shell out even more money. I wonder if anyone has any ideas?

Many thanks for any help

grumbler

DJ123 said:

... mixer tap shower (Bristan Artisan AR2 THBSM C Thermostatic Bath Shower Mixer Tap.) 

bath or shower?

Regardless, if you managed to adjust the temperature first, but it then dropped gradually, this looks like some fault to me.

DJ123

Hi 
Thanks for the reply. It's a mixer tap that allows you to select between a bath or shower. This issue affects both the bath and shower temperature.

Jeepers_Creepers

No obvious explanation I can think of - that mixer should be decent quality, and is totally suited to your combi boiler.

Sometimes - rarely - a modern shower which has flow restrictors fitted for environmental (water-saving) reasons can reduce the hot flow through the boiler to the extent that it shuts off or cycles on and off, but I doubt very much that's what's happening here - modern boilers 'modulate' to cope with changing demand, rather than go 'on and off'. Ie they constantly adjust their output to match demand, like turning a gas hob up and down to keep a pan simmering. 

The only thing I can think of, then, is that perhaps debris from the installation is gathering in the thermostatic valve and preventing it from working properly. 

I'd contact Bristan first just to see if they have any ideas, but you'll almost certainly need to call the installer back to sort it.

(If it's debris, then I assume he didn't flush the boiler/pipes out properly). 

neilmcl

DJ123 said:

Hi 
Thanks for the reply. It's a mixer tap that allows you to select between a bath or shower. This issue affects both the bath and shower temperature.

How long does it take for the water to get fully hot in the sink? I ask this because in some installations the hot water takes such a circuitous route that it can take a minute or two for the hot water to get up to temperature. At my parents for example I have to let the hot water tap run for a few minutes first before using the shower, whereas in mine the bathroom is directly above the combi and the hot water is pretty much instant.

DJ123

Jeepers_Creepers - thanks - I hadn't thought to contact Bristan. That's a great idea

neilmcl - thanks and good suggestion. The water takes around 1 minute to get up to temperature I would say, but I am definitely leaving it long enough to get up to temp (I had a miserable 37 degree shower in it today haha). I know exactly what you're talking about though, as one of our taps takes around 5 litres of water to flow out of it before getting up to temp. Not all taps in the house are like that.

Norman_Castle

Contact the installer, as they fitted both they can't blame someone else. A decent company should consider this their responsibility until proven otherwise. Who supplied the tap, you or them?

DJ123

Hi Norman_Castle, they supplied the tap. I think you're right too. I guess I'm trying not to get them involved unless I have to, as I imagine it's going to involve a fee. I guess I can at least try asking though

Rosa_Damascena

Sounds like a dodgy valve to me but I'm no expert. These things are easily replaced but the cost should not be yours to bear.

DJ123

Thanks for your help everyone. I have contacted Bristan, and they think that the cartridge needs replacing. It's all under warranty, and they were going to send an engineer out to fix it without any charge. Only problem is, they don't cover my area (weird - I live in a large town!) So now they are sending out a replacement cartridge, and I have to either fit it myself, or get a plumber to do it. Bristan will cover all the plumber costs up to £89. 

TELLIT01

You really should have got the installers back rather than getting involved with the manufacturer.  Your contract is with the installer and it is their job to address problems whilst the system is under warranty.  The installer may appreciate you identifying the problem but may not.