Trying to remove shower thermostatic cartridge - help please

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Hi - I'm new to these boards but am looking for some help please. We have a shower cabinet, not sure of the shower type but the control panel says "SaniNova by Maax". We've been in the house 2 years and the shower has been fine until recently where we now get temperature fluctuations and struggle to get a nice warm shower - the only way to get any warmth in it is to run the bathroom hot tap until that is hot (almost scalding) and then turn on the shower, but even then it tends to only be tepid, which is no fun. I've researched this a bit and reckon it could be the thermostatic cartridge. Our plumber says that the combi boiler is OK. The nice people at Showerdoc say they need to see it removed from the housing to be able to identify it, and therein lies my problem, I can't remove it.

I've removed the temperature control knob and the plastic temperature lock beneath it but am unable to remove the cartridge (turning anti-clockwise). All I'm doing is churning the brass knurled nut (see pic). I couldn't see a grub screw to remove (as mentioned for some cartridges) but there is a circlip in front of the nut - does that need removed? Showerdoc also said I need to remove the chrome plate and try to get a spanner on the two slots on the front of the cartridge as this one looks like its screwed in to the body. However, looking at it, even if I manage to unscrew the chrome plate, I don't think I can get a spanner onto the cartridge as it's recessed - unless I'm missing something. Any help/guidance would be most appreciated - the wife & kids are getting fed up with not having hot showers.
 
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Sorry, I said I was new to this. I thought I'd included a picture in the post, but obviously not. I'll try again here..
 

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OK thanks jeff the gasman. Do you mean the chrome surround? If so, wouldn't this still leave the flats of the cartridge inside the housing so not sure how I'd get a spanner on them. Could you suggest how to do this please. I've tried by hand (anti-clockwise) but it won't shift.
 
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I would look at your hot water supply before blaming the shower unit. How is the water heated?
 
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Thanks spareshunter. The hot water is provided by a Baxi combi-boiler. This has recently been checked by a plumber who said he didn't think that it was the cause of our problems. Having said that, it doesn't always fire up straight away when we demand hot-water, so there could be an issue there. Then again, we can have almost scalding water coming out of the bathroom sink tap and only tepid from the shower! Any ideas please???
 
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This has recently been checked by a plumber who said he didn't think that it was the cause of our problems
You need someone other than a plumber. If he just looked at it and came to this conclusion on what you have just posted then look elsewhere for advise. Always the first port of call is the heat source when a shower goes hot and cold and the other taps in the dwelling are working as they should.
 
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To be fair to him, he did a bit more than just look at it, but in the end he couldn't suggest anything other than that we might need a new shower - he didn't even mention that it could be the cartridge. What sort of person do I need, if not a plumber?
 
D

durhamplumber

my advice would be a new shower.if the hot water is constantly hot from a tap then i would say its your shower thats the problem.By the time you have dismantled it,traced the part.dug out the old part.o rings etc they are not worth pratting on with.
 
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To be fair to him, he did a bit more than just look at it, but in the end he couldn't suggest anything other than that we might need a new shower - he didn't even mention that it could be the cartridge. What sort of person do I need, if not a plumber?
Someone who understands combi boilers and a Gas Safe person. You haven't mentioned the specific model of boiler which could be a pointer. Just what did your "plumber" do? You have to be specific if you want an honest reply.

my advice would be a new shower.if the hot water is constantly hot from a tap then i would say its your shower thats the problem.By the time you have dismantled it,traced the part.dug out the old part.o rings etc they are not worth pratting on with.
Yes they are especially when they are buried in the wall. "We repair when others despair".
 
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Someone who understands combi boilers and a Gas Safe person. You haven't mentioned the specific model of boiler which could be a pointer. Just what did your "plumber" do? You have to be specific if you want an honest reply.

The boiler is a Baxi Combi 105e. Since I've been trying to remove the cartridge, the last couple of times I've turned on the shower (without first turning on the hot tap to get the water hot) the boiler has tripped out with a hot water temperature fault light, and I've had to switch it off and on again. It's then fired up OK (with the sink hot tap 1st). So maybe it is the boiler? Should I be looking for a heating engineer, not "just" a plumber?
 
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my advice would be a new shower.if the hot water is constantly hot from a tap then i would say its your shower thats the problem.By the time you have dismantled it,traced the part.dug out the old part.o rings etc they are not worth pratting on with.

I really don't want to have to replace the shower as it's part of a steam cabinet, and whilst it's accessible as the cabinet can be moved away from the wall, I suspect I'll struggle to find a shower to replace it.
 
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I very much doubt it is the boiler at fault ( on this occasion ).

Looks as if it may need a special tool.

Have you showed that photo to showerdoc?
 
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