Plumbing Question - Shower not hot

[Mark Wright]

I know I'm cheating a bit but I'd put money on it that some of you guys know a bit about plumbing.

Basically, the Shower doesn't get that hot. I don't think it has since the boiler( I'm not 100% this was when) was changed. But the Sink and everywhere else does. They paid to have a new shower fitting etc put in but it's still not that hot. I don't have the heart to tell the owner an old lady that I don't think this has fixed the problem.
Obviously, she will notice eventually.
P.S. I know nothing at all about plumbing.
Thanks in advance.

 

[mainline]

I know I'm cheating a bit but I'd put money on it that some of you guys know a bit about plumbing.

Basically, the Shower doesn't get that hot. I don't think it has since the boiler( I'm not 100% this was when) was changed. But the Sink and everywhere else does. They paid to have a new shower fitting etc put in but it's still not that hot. I don't have the heart to tell the owner an old lady that I don't think this has fixed the problem.
Obviously, she will notice eventually.
P.S. I know nothing at all about plumbing.
Thanks in advance.

Is this an electric shower, if so what is the Kw.

 

[Mark Wright]

No, it's not electric.

Another thing ill add if anyone knows a good and honest plumber in the Surrey area?

 

[mainline]

No, it's not electric.

Another thing ill add if anyone knows a good and honest plumber in the Surrey area?

If it's a thermostat type mixer, then it will most likely be a fault with the thermostat.
I have also seen these where the hot/cold are the wrong way around, which can damage it.

 

[loz2754]

Mixer showers usually have a stop on the temperature control which is set fairly low. You bypass it by pressing a button to enable you to turn it further.

 

[Mark Wright]

I'm suspecting it is something to do with the water thermostat? the shower has been replaced - presumably when they did this he would have had access to the mixer unit and if so would have set it appropriately.

Where would the water thermostat be located?

Again ill point out all sinks get hot/boiling.

 

[Intoelectrics]

I'm suspecting it is something to do with the water thermostat? the shower has been replaced - presumably when they did this he would have had access to the mixer unit and if so would have set it appropriately.

Where would the water thermostat be located?

Again ill point out all sinks get hot/boiling.

If the water is hot at all other outlets then this directly points to the shower mixer valve as first point of call. However, I have come across once a bath that had the same issue, but this was down to the water flow rate, where if you turned down the hot tap to slow the flow rate the boiler would keep up.

I'm assuming its a combi boiler?

 

[MJPD29]

Is it possible this is due to water flow/pressure issues?

 

[Avo Mk8]

When you say "not that hot" do you mean it doesn't reach 38 degrees? The thermostatic cartridge would normally be set up to 38 max by an adjustable stop in the mixer, and as has been said you would normally have to press the little safety button to get any hotter. If not set properly by the installer that just might be contributing to the problem. Installation instructions cover all this stuff, but nobody (Edit - make that no plumber) seems to read them

 

[Mark Wright]

When you say "not that hot" do you mean it doesn't reach 38 degrees? The thermostatic cartridge would normally be set up to 38 max by an adjustable stop in the mixer, and as has been said you would normally have to press the little safety button to get any hotter. If not set properly by the installer that just might be contributing to the problem. Installation instructions cover all this stuff, but nobody (Edit - make that no plumber) seems to read them

Great question - I guess I should find some way of measuring the the temperature.



The tap is turned all the way up past the safety button. I mean for a little old lady in summer it's ok but in winter I personally wouldn't be happy.

 

[Avo Mk8]

The tap is turned all the way up past the safety button. I mean for a little old lady in summer it's ok but in winter I personally wouldn't be happy.

you're right, there must be something wrong if it's on max and still only lukewarm!

 

[Mark Wright]

Any ideas what might cause this? Again all other taps can reach very hot/boiling.
I assume without wasting too much money a good plumber could diagnose this in 5 minutes?

 

[timhoward]

Any ideas what might cause this? Again all other taps can reach very hot/boiling.
I assume without wasting too much money a good plumber could diagnose this in 5 minutes?

A good plumber could probably give you an answer in 15 minutes. It would be tempting to immediately blame the shower itself as it's the most logical explanation.
Personally I'd turn water off (assuming combi boiler this is enough, otherwise more care needed), open downstairs and upstairs taps to drain down (and allow air in to avoid a vacuum) and remove shower unit.
Then fit a 1/2 inch BSP to 15mm flexible hose to each side, and put a normal isolator on the 15mm end.
Then turn water on again, and try the hot side as a simple tap.
If it gets as hot as the other taps, it's the shower. If it doesn't there's a curious problem that needs further investigation.

 

[Mark Wright]

Thanks for the response.
The shower is brand new the previous one was worse. I have the manual. I was thinking take it apart adjust the valve/callibrate so in theory would allow maximum hot water, if after this its still lukewarm its not the shower the fault lies elsewhere

 

[Mark Wright]

A good plumber could probably give you an answer in 15 minutes. It would be tempting to immediately blame the shower itself as it's the most logical explanation.
Personally I'd turn water off (assuming combi boiler this is enough, otherwise more care needed), open downstairs and upstairs taps to drain down (and allow air in to avoid a vacuum) and remove shower unit.
Then fit a 1/2 inch BSP to 15mm flexible hose to each side, and put a normal isolator on the 15mm end.
Then turn water on again, and try the hot side as a simple tap.
If it gets as hot as the other taps, it's the shower. If it doesn't there's a curious problem that needs further investigation.

I just tried to take this in. Now I know nothing about plumbing but I assume a good plumber could do this in half an hour and rule out the shower? I could also check the pressure doing this?

 

[timhoward]

I just tried to take this in. Now I know nothing about plumbing but I assume a good plumber could do this in half an hour and rule out the shower? I could also check the pressure doing this?

A good plumber might have an even better idea, but from a logical stance checking the hot feed to the shower is the aim and that's one way it occurred to me to do it. Depending on the details of the plumbing and the presence of compression fittings or john guest push-fit fittings there may be even easier ways.
I'd go on your local Facebook free/swap group and ask for a recommendation of a good local plumber who can help diagnose a problem with a mixer shower.

 

[Mark Wright]

Thanks for all your help.

 

[loz2754]

Don't forget we have a plumbers forum next door

 

[brianmoooore]

What type of shower is this? Thermostatic bar type?

 

[LukeD]

lets use the example its a "IBOX" Mixer (Bloody fantastic and good value ) . Many fitters dont bother setting the mixer up correctly and tell customers "showers are not legally as hot as they use to be " etc etc . Even the Override setting button is worthless if the mixer itself has been set too low . Many mixers instructions clearly show exactly how to install and test using a Digital temp gauge etc .5 mins work and many cannot be bothered ..