Thermostatic shower cartridge replacement - Help Please!

[teetoo]

Hi,

My showers giving out cold water most times. Ive been told by many that its the thermostatic cartridge. The shower is a concealed shower unit built into the wall, so i had to take the metal plate off before i could get to the cartridge. I looked everywhere for a brand name but could not find one. I took some pics and wondered if anyone on here can advice which one it is or where i can get one that fits. I dont have the money to spend hundreds getting a new shower unit installed, so am trying my best to find the cartridge or a supplier

thanks, Sid

 

[scotty plumber]

Hi first of all i am sorry but i do not know the type/make of shower you have but i am sure somebody else will however i know that similar looking cartridges like the mira 722 will set you back about 130quid! Also when taking apart parts of a thermostatic shower unit keep all parts in order from left to right as it make's it a lot easier when puttting it back together again! good luck!

 

[PlumbBobBob]

hi sid welcome to the forums. if you send those pictures to the shower doctor (do a google search) they should be able to help you. also probably good idea to take your mobile no. off public forum never know who will see it.

 

[WHPES]

If your shower works some of the times and not others, the moving parts may just need freeing off and greasing.

 

[Paulus]

You should find a filter on the hot water inlet to the valve. It's worth checking if this is blocked with debris before forking out for a new thermostat.

 

[teetoo]

Steveb - thanks for the advise i already showed the pics to the shower doctor waiting to hear back from them

WHPES - thanks, what moving parts are you referring to?

Paulus - Thanks, i will check the filter, however i don't think thats the issue as i do get hot water only for about 10 seconds then it becomes cold again and the only way to get hot water once again is to close the tap, then open wait for about 20 seconds and get luke warm water coming through again for about 10 seconds - having said all this the hot water in the house functions quite bizarrely. Hot water can only be used in one place at a time i.e. if i have the hot water running in the sink and the shower is turned on then the sink water becomes cold. Same as downstairs if the hot water is turned on while washing dishes and i the hot water in the bathroom is turned on then the kitchen's hot water becomes cold. I thought this may have to do with the combi boiler and called the guy who installed it. He confidently said it wasnt the boiler and was purely to do with the shower's thermostatic function. I even had a local boiler repair person come over and he couldnt fault the boiler. All this is driving me mad - i'm just hoping the thermostatic adapter fixes the issue.

Also its worth noting that when i called the local plumber to have a check he opened the valve and took out the thermostatic cartridge...and to no surprise the water came spurting out, we had to close it off from the outside. The funny thing is he said it felt like it was coming out one inlet and the water was cold - should it have been warm or is that the thermostatic cartridge's function to make the water warm?

 

[PlumbBobBob]

teetoo all the cartridge does is mix the water. you have to have hot on one side and cold on the other side coming in to the shower.

 

[Paulus]

As steve b says.

You say that when the plumber took out the cartridge there was only cold water from one inlet, there should have been hot water from the other inlet. If not it sounds like you have a blockage in the hot water feed. The plumber should have picked up on this.

 

[WHPES]

Could be a jammed check valve. If you only get water from one side it's not the cartridge. From what you describe it sounds like it's not been plumbed in correctly to begin with.

 

[Phil]

Steveb - thanks for the advise i already showed the pics to the shower doctor waiting to hear back from them

WHPES - thanks, what moving parts are you referring to?

Paulus - Thanks, i will check the filter, however i don't think thats the issue as i do get hot water only for about 10 seconds then it becomes cold again and the only way to get hot water once again is to close the tap, then open wait for about 20 seconds and get luke warm water coming through again for about 10 seconds - having said all this the hot water in the house functions quite bizarrely. Hot water can only be used in one place at a time i.e. if i have the hot water running in the sink and the shower is turned on then the sink water becomes cold. Same as downstairs if the hot water is turned on while washing dishes and i the hot water in the bathroom is turned on then the kitchen's hot water becomes cold. I thought this may have to do with the combi boiler and called the guy who installed it. He confidently said it wasnt the boiler and was purely to do with the shower's thermostatic function. I even had a local boiler repair person come over and he couldnt fault the boiler. All this is driving me mad - i'm just hoping the thermostatic adapter fixes the issue.

Also its worth noting that when i called the local plumber to have a check he opened the valve and took out the thermostatic cartridge...and to no surprise the water came spurting out, we had to close it off from the outside. The funny thing is he said it felt like it was coming out one inlet and the water was cold - should it have been warm or is that the thermostatic cartridge's function to make the water warm?

Do you mean he removed the cartridge live and then ran outside to turn the water off when he realised?

In those breif few seconds the boiler wouldn't have time to kick in anyway.

May not be the cartridge, what is the water pressure like, does the shower get hot when you run the cold basin tap?

 

[teetoo]

To answer you first question - yes, I just realised why there wasn't hot water is because the hot water outlet was closed off at the combi boiler at the time.

The water pressure is very good. I ran the cold basin tap and the shower pressure became noticeably low, warm (not hot!) water started emerging, but this time it was a constant flow of warm water which lasted several minutes- success

There is another way I found in getting constant flow of warm water - by putting the shower on low pressure I do get a constant flow of warm water lasting several minutes

So it seems as though pressure has a lot do with it. Doesnt the thermostatic cartridge controls the balance of hot and cold water? Maybe the pressure function of my current thermostatic cartridge does not work and is letting more cold water in than hot?


Thanks for all your help

 

[teetoo]

Can anyone tell me if the thermostatic cartridge controls the balance between hot and cold and also the pressure I.e if the cold water has lots of pressure and the hot water only a small amount then is it the cartridges job to balance the two and give equal pressure?

 

[nickelarsed]

thermostatic cartridges fix the temp not pressure. What's the hot like at other outlets? Do you get a strong flow from the hot at the sinks/basins?

 

[teetoo]

Yes they are strong at other outlets and could also be strong at the shower, but I never got to experience powerful hot shower...well tell a lie I have a couple of times, but then it dips to cold very quickly....I'm so confused if it's the cartridge or something else that's the issue

 

[nickelarsed]

well someone might correct me but sounds like it's either the shower, or maybe the pipework to it. As someone said worth checking the filters because it does sound like it's not receiving enough hot water. If you can isolate the shower it may be worth removing the shower, leaving the cold isolated and just turn on the hot (put a hose on the pipe). If you get a good flow of hot water, similar to other outlets then you know the pipework is good with no blockages, which just leaves the shower, probably the cartridge, presuming the filters are clear. If bad flow then you know it's the pipework to it.

 

[Phil]

The boiler can't keep up with the high water pressure as you've proved by turning on the cold tap, I would install a pressure reducing valve after the mains stoptap.

Turn on the cold kitchen tap and the basin/bath taps and see if the shower gets hot to test.

 

[teetoo]

I believe I've already got a pressure reducing valve, shown far left called the "water pressure gauge" in the manual. I believe the tiny red lever next to it allows you to control the pressure. I tried pulling it down as it currently on 1.75bar but should be less than 1.5, but it's jammed. Am I right in thinking that it is a user control - I don't see it being mentioned in the manual?


Tried the running of the cold water test, but water doesn't get hot. But I did notice that when shower on low then water does get warm. I believe if I reduce the cold water pressure then there will be a higher proportion of hot water, but how do I reduce the cold water pressure alone without affecting the hot water pressure

I see on the manual that variable central heating and domestic hot water controls are fitted on the user control of the boiler - do I need to adjust he DHW preheat facility?

 

[enragedlime]

I know I'm bumping this from years ago and bring it back from the dregs but there isn't an answer to this question, therefore for future readers of this thread, this is an IB Rubinetterie thermostatic cartridge in the original posters' images - Thermostatic Cartridge for IB Rubinetterie Concealed Shower Mixer Valves