Advice please on Shower going hot cold hot cold

[mrhill32]

Hi all,

For some reason my shower will not stay hot, it is hot for about 30s and then will go cold for about 10s and repeats this.

I have read forums and people say it could be the heat exchanger needing a clean or a sticky diverter valve but the taps for the sinks etc aren't doing this so does that mean the boiler is fine and the problem is actually with the shower?

I would greatly appreciate any help!!
thank you!

Stuart

 

[ShaunCorbs]

I would say it's your shower thermostat cartridge

 

[Harvest Fields]

What shower do you have?

 

[mrhill32]

Hi guys it is a Sirrus 1500 Antique shower i have been told

 

[JCplumb]

A quick google shows that to be a thermostatic shower. New thermostatic cartridge is the likely cure.

 

[mrhill32]

thank you, do you think i should replace this, (seems to cost around £75) or shall i just buy a new Thermostatic shower?

 

[ShaunCorbs]

thank you, do you think i should replace this, (seems to cost around £75) or shall i just buy a new Thermostatic shower?

Depends how old is the shower

 

[mrhill32]

I honestly don't know, we moved in 3 years ago, i have no idea how long it was in beforehand

 

[Harvest Fields]

Depends on the price of the cartridge I would say.

 

[mrhill32]

It seems the cartridge ranges from £75-£100, if i decide to get a new shower, will something like this be replaced easily (for example) Traditional Exposed Thermostatic Mixer Shower Bar Valve Rainfall Bath Bathroom | eBay

 

[steadyon]

1. You need to work out the centre distance between the pipes coming out of your wall. Measure the distance between the outside of the elbows, and subtract the diameter of one elbow (assuming they are round). If this is 150mm most bar mixer showers will fit.

2. You will also need to check that there will be enough exposed pipe when you remove the existing shower to enable the new one to be connected.

3. You need to make sure that, if you have a low pressure supply (tanks in loft / airing cupboard, no pump) that the shower you choose will give you a decent flow on 0.1 bar of pressure, although you might risk a 0.2 bar one.

4. The one you have linked to looks like a "no name" import, so its highly unlikely you'll ever be able to get spares for it.

5. Have a look at Bristan bar mixers.

 

[mrhill32]

Thank you for the in depth response, I will take a look at what you suggest

 

[JCplumb]

If you can figure out how to get at the thermostatic cartridge, whip it out and take it to a plumbers merchants they may have an exact match or be able to source one for a lot less than £75.
Remember to turn the water off before attempting to dismantle it.
There are a couple of common generic thermostatic valves I think the most common are called type 1 and type 2, I know of a type 6, so not sure how many generic types there are.