Plumbing Question - Shower not hot

brianmoooore · May 5, 2023

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

Mark Wright · May 5, 2023

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

[ElectriciansForums.net] Plumbing Question - Shower not hot

Mark Wright · May 5, 2023

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

LukeD · May 5, 2023

Mark Wright said:
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 · May 5, 2023

brianmoooore said:
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 · May 5, 2023

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 · May 5, 2023

Mark Wright said:
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 · May 5, 2023

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 · May 5, 2023

brianmoooore said:
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 · May 5, 2023

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 · May 6, 2023

brianmoooore said:
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 · May 6, 2023

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 · May 6, 2023

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 · May 6, 2023

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 · May 6, 2023

Mark Wright said:
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.

Mark Wright said:
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 · May 6, 2023

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 · May 6, 2023

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 · May 6, 2023

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

Mark Wright · May 6, 2023

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

brianmoooore · May 6, 2023

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

LukeD · May 6, 2023

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 · May 6, 2023

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 · May 6, 2023

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 · May 6, 2023

Can you

mainline said:
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 · May 6, 2023

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.

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