Max temp too low - new thermostatic shower mixer valve

[AnnaD2002]

Hi, I hope someone can help so I can be armed with a bit of knowledge before trying to sort this out with my builder/plumber.

We have recently had new central heating (combi boiler) and a new shower installed with a concealed thermostatic mixer valve. All the taps in the house can be turned up to a very high temperature but the shower only runs to a max of just-a-bit-hotter than lukewarm which is not nearly hot enough for me (will definitely not be in the winter). My question is, idoes this sound like a maximum temperature restrictor/safety mechanism in the shower valve? It goes hot for a split second at the highest setting then back to lukewarm.

As it is concealed (it is this model http://www.bathdisc.co.uk/product_info.php?cPath=32_122&products_id=1438) does this mean having to pull tiles out to adjust or would it be in the valve unit itself and therefore less disruptive?

Any advice would be much appreciated!

 

[Charnwood]

May need:
Commissioning properly. Probably described in the Installation Manual (IM)
Presure Reducing valve in the cold feed. Probably suggested in the IM
Flow restrictor on the cold feed. Probably suggested in the IM

Commissioning should be able to be done with the shower in situ
The other 2 options involve adding something to the cool feed pipework

 

[AnnaD2002]

Thanks Charnwood.
Spoke to plumber suggesting below, and he is convinced it is the manufacturer's setting to prevent scalding and refuses to make any adjustments. Is this fair? Incidentally I tested the temperature this moring and it is between 39.5 and 40C - am I just being fussy?!

 

[Charnwood]

he is convinced it is the manufacturer's setting to prevent scalding and refuses to make any adjustments. Is this fair?

Fair, almost certainly not because most, if not all, manufacturers instructions state that the shower needs commissioning to set the temperature correct. The max temp from a shower mixer should be in the mid-40s°C.

Showers with a temperature-stop are set at 38°C. Pushing the stop allows the temperature control to be turned further allowing the temperature to be raised a few degrees.

If 39.5 - 40°C is the max you can get there is something wrong. Not necessarily with the shower but more likely the installation/commissioning.
This could be a pressure differential problem, a flow rate problem or a hot-inlet problem, i.e. inefficient boiler (not likely). Does the boiler deliver very hot water to taps?

 

[AnnaD2002]

Thank you.
Yes the boiler does deliver very hot water to the taps so musn't be a problem with the boiler. Unfortunately there is no convincing our builder- plumber that it is anything other than the manufacturer's settings and he won't investigate it and I just want to see the back of him now. Would this be a very costly/disruptive thing to rectify if we got someone else in to do it i.e. sort out differential problem or flow rate problem

 

[Dan Robinson]

If installed properly it should be a 20 minute job.

If it is a built in shower let's hope the hot and cold feeds are the right way round.

 

[AnnaD2002]

0k thanks that's reassuring to know. thanks for all your advice.

 

[Charnwood]

Commisioning: fairly easy to do. Did he leave any instructions for the shower?

Pressure or flow rate: not so simple. Both require something fitting to the cold pipework.

When you say builder/plumber do you mean 'jack of all trades, master of none'?

 

[JohnD]

if you have not got the installation instructions, you can probably download them from the manufacturer's website.

have a look through it.

 

[Charnwood]

I looked and could not find a manual.........





just a thermostatic!

There is a brochure and a line drawing, but that's your lot.

 

[AnnaD2002]

Ah thank you for checking anyway! I have been trying to get hold of the shop I bought it from to see if that model does have a max temperature inhibitor

 

[Charnwood]

You could contact Crosswater direct.

Tel: 0845 873 8840
Fax: 0845 873 8841
Email: [email protected]

 

[JohnD]

I thought it was normal for modern shower mixers to have a max temp limit. Mine has a "release button" to go past the limit. Isn't that usual?

 

[AnnaD2002]

Hi - mine doesn't have a release button.

I have called the manufacturer and they have said it could be either the fact that the pressure is unbalanced so solved with a pressure reducing vavle to the cold feed; or the cartridge needs recalibrating. I am going to go back tonight and check the balance (flushing toilet, cold tap in basin on, shower on to max).

The plumber refuses to recalibrate it if it isn't the latter. I have just had a shouting match with him on the phone, not pleasant - he accused me of telling him he had installed it badly. So anyway I really hope it is the pressure thing.

 

[AnnaD2002]

And yes Charnwood I do mean jack of all trades master of none - not impressed at all.