Shower valve adjustment

[Elliotb95]

Evening all- I have just moved into a new house and the shower max temperature is only luke warm at best. All the other taps run hot water so I think it’s something to do with the shower. Also the bath only runs Luke warm water too.

The model of the shower is Kartell Pure Thermostatic Exposed Bar Shower - Overhead Drencher - Sliding Handset.

I have seen online that there maybe a valve under the bath which I can adjust but I can’t see anything.

I don’t suppose anyone else has had the same issue?

Thanks in advance.

 

[terryplumb]

What provides your hot water ,is it a combi boiler ,or from stored hot water ( cylinder) ?

 

[Elliotb95]

Hi thanks for the reply. It’s from a combo boiler. I don’t think this is the issue as all the other taps provide really hot water.

 

[terryplumb]

Hi thanks for the reply. It’s from a combo boiler. I don’t think this is the issue as all the other taps provide really hot water.

Not quite ,the bath hot tap doesn't.
If bath hot is turned half on ,does it then give the same temperature as other hot taps ?
Does your shower have any kind of pump fitted to hot pipework ?

 

[CBW]

Probably is a thermostatic mixing valve, although usually just for baths. Looks something like this:

 

[Elliotb95]

Thanks both. True the bath gives exactly the same heat as the shower when fully on hot. From all I can see under the bath there isn’t really any thing like that. I will upload a picture of what I can see under the bath if that is ok?

 

[terryplumb]

If you run your shower with the flow reduced ,do you then get the desired temperature . The handle on the left controls the flow ,the right one controls temperature .

 

[Elliotb95]

Hi terry, no still the same issue. Also the soaked shower head is even colder not sure if that helps any more.

 

[terryplumb]

The thermostatic valve may need to be adjusted ,to increase the hot temperature range ,or it may be just kaput !!

 

[Elliotb95]

Yeah a few people think it will be the valve. Just the only problem I have is I have no clue where it is lol.. all my plumbers are busy till new year so will have to wait if I can’t find it myself

 

[terryplumb]

I am referring to the actual shower valve itself ,not a separate blending valve like one pictured earlier. There would be absolutely no point whatsoever in having one linked to your thermostatic Kartell valve.

 

[Elliotb95]

But would that explain why my bath isn’t getting hot water too? If it’s the shower valve would that affect the bath? The bath on and off has its own faucets

 

[terryplumb]

A combi boiler can rise water temperature by X degrees for a given flow of water. For example if boiler delivers 50 degrees c at a flow rate of 9 litres per minute ,a tap giving 9 litres per minute would give temp of 50c. Bath taps ,and the size of the pipework going to them, can deliver more than other tap outlets ,so bath can be filled quicker. So if yours deliver 15 litres per min when fully open ,there is a corresponding drop in temperature ,as the water flows through the boiler much quicker and can't get as hot. That's why when you reduce the hot bath taps flow ,you get a hotter temp.
Your mixer shower has much smaller pipework ,and restrictive outlets ( shower heads ) so will not suffer from the same problem ( unless it has a pump ,hence me asking earlier ).
Your problem is your shower.
If you can isolate the cold supply to the shower only ,there may be isolation valves on its pipework ,you can then see what temperature it will give you. If its nice and hot ,that's a sure sign that the valve itself isn't blending properly.

 

[JohnD]

Go out and buy a thermometer, and a bucket.

Then you can measure the actual temperatures from your various hot (AND COLD) taps, and by accurately timing how long it takes to fill the bucket, you can calculate how many litres per minute each tap is delivering.

You will be surprised how much information can be gleaned from that data, and what can be diagnosed.

 

[JohnD]

Hi thanks for the reply. It’s from a combo boiler. I don’t think this is the issue as all the other taps provide really hot water.

Yes it is.