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 ..

 

[Mark Wright]

What type of shower is this? Thermostatic bar type?

Yep.

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 ..

I've looked at the manual calibration section and taken the dial off etc and had it on Max and still not hot.

But again I know nothing about plumbing.

*But the previous shower worked at some point then didn't
* This is a new shower so should be a new cartridge valve.
*The sink a meter away get boiling hot.

I think at some point it's gonna have to come off the wall and just see without anthing connected does it get hot and then we know where we stand.

 

[brianmoooore]

Some bar showers have filters sandwiched inside the connections to the wall.
Did you turn the shaft of the temp setting end with the knob off?

 

[Mark Wright]

Some bar showers have filters sandwiched inside the connections to the wall.

Didn't know that but don't think I saw anything in the manual about it.

Did you turn the shaft of the temp setting end with the knob off?

The instructions you take it all off including the safety thing. Then connect the nob again and turn. I turned it to max.

 

[brianmoooore]

The safety stop and end stops are built into the knob. with the knob off, mark the shaft so that you know where it was, then turn the shaft whichever direction is hotter and see if that solves the problem.
If the knob was removed and put back in the wrong position, then the calibration (if the knob is marked in degrees) and the correct 'max' temp is lost.

 

[Mark Wright]

Thanks I've done all that it is on absolute max and its not hot. Thanks for the suggestion though.

 

[brianmoooore]

Did you turn the shaft further than it would go with the knob on?

 

[Mark Wright]

Here is the manual it seems pretty simple -unless i'm being totally dense I have turned it to the total maximum

 

[Mark Wright]

Suggested on the plumbing sister site isolate the cold water - Where would the cold only isolator be?
Just for testing.

 

[LukeD]

Suggested on the plumbing sister site isolate the cold water - Where would the cold only isolator be?
Just for testing.

THis ...test the temp of the hot water pipe before and after the mixer. Then if really different .Remove mixer and test flow of hot water . I hate these mixers with all my heart .For me its "ibox" or nothing

hansgrohe iBox 01800180 Universal Fitting Set 1/2 and 3/4 - https://www.plumb2u.com/PBSCProduct.asp?ItmID=28449893&AccID=122267&PGFLngID=1&gclid=Cj0KCQjw0tKiBhC6ARIsAAOXutkBbybNHcpq9ANEIeqJb2cL0y71t7LkCltRobB4O9eCWilzqJfKTUkaAiCxEALw%5FwcB&gad=1 They really are amazing and Ive used them in Bathrooms that cost a fortune .

 

[DPG]

Did you turn the shaft further than it would go with the knob on?

I was going to comment on this post, but I fear it would have been juvenile, so I'll refrain.

 

[Mark Wright]

First thanks everyone for your patience.

The pipe is in the wall. But I guess I should be able to feel the pipe on the tiny bit on left entering the mixer.

 

[LukeD]

First thanks everyone for your patience.

The pipe is in the wall. But I guess I should be able to feel the pipe on the tiny bit on left entering the mixer.

Fastest way is remove cartridge and run hot only if the temp is fine. Mixer is caput or not working set up correctly . hate to say it .... they are sold under a few brand names and the cartridges are always playing up. they HATE hard water

 

[brianmoooore]

Next step is to turn off both hot and cold supplies to the shower and remove the bar by unscrewing both nuts where the pipes come out of the wall. Any filters that are fitted will come off with the bar and be inside the nuts.
Close the shower doors and turn the hot supply back on. Check that the water coming out of the pipe is hot and that it is coming out of the correct pipe.

P.S. Where does the hot water come from? A combi boiler or cylinder?

 

[Mark Wright]

Next step is to turn off both hot and cold supplies to the shower and remove the bar by unscrewing both nuts where the pipes come out of the wall. Any filters that are fitted will come off with the bar and be inside the nuts.
Close the shower doors and turn the hot supply back on. Check that the water coming out of the pipe is hot and that it is coming out of the correct pipe.

P.S. Where does the hot water come from? A combi boiler or cylinder?

Yep I think thats what going to have to be done. I believe its a low pressure gravity system? so hot water from a tank. I think this needs to be done. Luckily I know a bit of an action man and I might ask for his help

Thanks again for your replies.

 

[brianmoooore]

If it's a gravity system without a pump, you're going to struggle to get this to work. From the Esteem website, it looks like your shower needs a minimum pressure of 0.2 or 0.4 bar, depending on the model. This equates to a minimum head of water of either 2m or 4m respectively, and that's without taking pipe losses into account.
In a two storey property, with the tank in the loft and the shower in a ground floor room, you might just about get it to work OK if it's the 0.2 bar version, but any other combination is going to be less than satisfactory.

 

[Mark Wright]

If it's a gravity system without a pump, you're going to struggle to get this to work. From the Esteem website, it looks like your shower needs a minimum pressure of 0.2 or 0.4 bar, depending on the model. This equates to a minimum head of water of either 2m or 4m respectively, and that's without taking pipe losses into account.
In a two storey property, with the tank in the loft and the shower in a ground floor room, you might just about get it to work OK if it's the 0.2 bar version, but any other combination is going to be less than satisfactory.

I have no idea what you just said but I'm learning and ill look into it. Thanks again for your reply.

 

[Mark Wright]

Ok another thought I'm having is maybe this has happened since the new boiler - so the hot water pump is not working correctly?


Bear with me I think the boiler is "GREENSTAR FS 30CDi & FS 42CDi Regular - Worcester Bosch" should a pump be coming on to pump the hot water in shower?

Or am I way off.

Lets say there is not enough pressure for the hot water - how can this be increased?

 

[LukeD]

You say the hot water is fine in the basin/kitchen " 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. " SO the supply of hot water is not the issue . The issue is probably not the boiler .Its the mixer valve hindering the full flow and limiting it temp. The fastest way .....If the supplies have isolators . Undo the got one and attach a flexi pipe and then open the isolation valve and check the temp. Or just remove the valve cartridge and see if the water gets a lot hotter and matches the kitchen sink etc etc

 

[Mark Wright]

Ok I have found a good plumber listed in the area. Do you think if I do this I sound like a total A hole or its ok?

I say I want the mixer off - and test the temperature of the hot water enetring the mixer
I want the pressure tested for bar value.
Mixer put back on wall.
I think an hour should be enough time.

Then ill decided what to do next.

 

[LukeD]

Yep I think thats what going to have to be done. I believe its a low pressure gravity system? so hot water from a tank. I think this needs to be done. Luckily I know a bit of an action man and I might ask for his help

Thanks again for your replies.

Ok I have found a good plumber listed in the area. Do you think if I do this I sound like a total A hole or its ok?

I say I want the mixer off - and test the temperature of the hot water enetring the mixer
I want the pressure tested for bar value.
Mixer put back on wall.
I think an hour should be enough time.

Then ill decided what to do next.

THis is where it can go wrong. We need to know what his responsibilities where .Ive fitted taps that a client told me to knowing the pressure was wrong and the hard water would kill the ceramic valves . But they did not listen . I got paid as I made sure I emailed them my concerns) If he was asked to just swap over the mixer , did he provide it , did he recommend it , did he check the entire system before etc etc etc ? The whole picture has to be painted first !

A good DIY person if there is access could work out the issue in 15 mins . leave the mixer on. Find under bath isolators (With luck full bore types !!) run only hot .Using a digital temp gauge gun . See temp of water before shower mixer and after . I really think its a easy "fault find" . Even just checking the hot inlet pipe by hand will soon tell you if its hotter !

 

[brianmoooore]

The boilers you list are conventional , not combi rubbish, so it looks like you probably do have a gravity hot water system, fed from a tank in the loft. Hopefully, the cold water supply to the shower is also from the same tank.
The problem is almost certainly that the new shower has a higher minimum pressure requirement than the original.
It is becoming almost impossible to find taps, mixers, showers, etc. with really low minimum pressures since the rise of the combi boiler and a regulation change some years ago that replaced a minimum flow rate with so called water saving specification.
To make this work, I suspect a shower booster pump will have to be fitted.

 

[plugsandsparks]

There is the other think to check and thats the source of the hot and cold. Typically gravity fed shower mixers require that the cold supply also comes from the same header tank as the hot supply. Its possible that the mixer is not suitable for gravity supply and if the cold is coming directly from the mains it may be pushing past the mixer thus diluting the incoming hot even from the mixer is on full hot.
Suggest ask plumber whether mixer is even suitable for the install..

 

[LukeD]

YOu sure there is a Hot water tank in the loft ??

 

[Mark Wright]

Water tank in loft
Hot water tank upstairs
Boiler Kitchen
Shower down stairs.

 

[brianmoooore]

In that case, the 0.4 bar version may have been fitted. Can you determine the exact model?

 

[LukeD]

Here is a "tangent " to the debate ..... !! Ive seen the very reverse . And a child was badly injured .The water came from the shower at full temp causing the child to "throw itself through a shower door . NO matter what .There should be a "master " control that limits showers and taps in homes . I use valves to ensure when taps are open the volume of water entering a basin etc is not to much and sprays all over the place .But also to ensure that people dont get scalded .

 

[Mark Wright]

Thanks guys again for all your input.

Here is a link to the manual. If you can't download let me know
https://tinyurl.com/3p6un49r

Better upload https://tinyurl.com/49rfynrd

 

[mainline]

We still don’t know if this is gravity fed or not as it could be an unvented tank and the header tank could be for central heating.

Run a hot water tap and check if the header tank ball cock starts putting water in.
Then do the same with shower just using cold.

 

[LukeD]

Can you

We still don’t know if this is gravity fed or not as it could be an unvented tank and the header tank could be for central heating.

Run a hot water tap and check if the header tank ball cock starts putting water in.
Then do the same with shower just using cold.

exactly .....And God bless the King !

 

[brianmoooore]

The manual confirms you have the version with a min pressure of 0.4 bar, so it's odds on that this is the problem.
Manual also confirms that there are inlet filters (part #3).
The filter also incorporates check valves, which aren't needed if both hot and cold supplies come from the same header tank. Removing the hot one may solve the problem, to a degree, at least.