Thermostatic mixing valves - rebuild?

[julianf]

The thermostatic mixing valve on our thermal store is misbehaving. Ie will start spitting out cold, when theres plenty in the store, etc.
Running through its range of settings (screwing the top in and out) does not resolve it.

This is the valve -

Im fairly sure its a Gledhill XC007.


Theyre £120 to replace : (

I was hoping there would be a rebuild kit available, but i have not found one.


I found this in my box-o-junk -

Its a valve by someone else, but the top implies it only goes to 40c?

So i guess thats useless to me.



My question is simple -

What should i do? Spend £120 on the gledhill, and just replace, like for like, or get some other valve? I dont mind if the ports are different, as theres plenty of space etc.

Thank you.

 

[123hotchef]

I used a cheaper one for my hot outside tap,

 

[julianf]

I used a cheaper one for my hot outside tap,

It seems there are plenty of cheap ones about, but the ports are much smaller, i assume for different applications?
This one is going direct on the side of the thermal store, so all the hot for the DHW passes through it. It maybe needs to be larger ports for the flow or something?

Thermal stores also get hotter than normal DHW tanks ever do - i guess that's a consideration in product choice?

I mean, I'm all for a cheaper alternative! I'm just cautious...

 

[123hotchef]

I am no plumber one for @Kayos maybe,

 

[Kayos]

Get the proper one, it should be fitted by a G3 qualified engineer but I know the response this forum will give that

 

[123hotchef]

Get the proper one, it should be fitted by a G3 qualified engineer but I know the response this forum will give that

ha ha yeah my mate said that about my unvented cylinder install also

 

[julianf]

Get the proper one, it should be fitted by a G3 qualified engineer but I know the response this forum will give that

Its a vented store, connected to a solid fuel appliance.

 

[julianf]

Its a vented store, connected to a solid fuel appliance.

ps. does that change the choice / recommendation of TMV at all?

 

[minimutly]

Get the proper one, it should be fitted by a G3 qualified engineer but I know the response this forum will give that

Lol...

 

[addjunkie]

Get the proper one, it should be fitted by a G3 qualified engineer but I know the response this forum will give that

I googled that, sounds like another tax on the competent heating engineer! With out digging further I guess being unvented its all about having PRV in the right places!

 

[Kayos]

I googled that, sounds like another tax on the competent heating engineer! With out digging further I guess being unvented its all about having PRV in the right places!

It's a tad more complex than that, the unvented course is usually done with the 5 yearly ACS

 

[Kayos]

Its a vented store, connected to a solid fuel appliance.

G3 still covers them, as it's connected to an uncontrolled heat source

 

[addjunkie]

It's a tad more complex than that, the unvented course is usually done with the 5 yearly ACS

Is that the thing they now do to-be gas safe?

This is what I found on the Kingspan site..makes it sound like a plumber tax, guess it depends on the levels of process complexity your used too.

What does a G3 course involve?​

A G3 qualification is typically a one to two-day course.

To do the course, you’ll need to prove you know your plumbing stuff already, for example by showing your NVQ 2 certificate or equivalent plumbing and heating qualification and experience.

You’ll be expected to do some study before the day, and the course itself will cover the safe installation and maintenance of unvented hot water storage systems in line with the G3 regulations.

There will then be an assessment. If you’re successful you receive an Unvented G3 Certificate, commonly called a G3 ticket, which is valid for five years.

In some parts of the UK, you may see G3 being called a HWSS course, and the qualification called a Hot Water Systems & Safety Certificate.

 

[julianf]

G3 still covers them, as it's connected to an uncontrolled heat source

Im sure you know more than me. Ive been looking about, and can find nothing that specifies G3 for vented work?

eg this -

G3 Certificate | Unvented Hot Water Storage Systems

Unvented G3 Certificate course – learn how to install and maintain unvented hot water storage systems (HWSS). Call 0800 345 7492.

www.accesstraininguk.co.uk

Its got "unvented" plastered all over it, as do all the other courses.

When we installed this tank, it was inspected by buildings control, along with the solid fuel appliance connected to it. At the time i was way more interested in meeting Document J specifications, and didn't think that much about the rest of it, but, again, so far as i could ever tell, no special paperwork was required to install a vented thermal store.

You have said otherwise. You are probably right, but, still, id like to be certain. Could you point me towards something that clarifies it for me, please?


In short, someone has told me that swapping a valve on vented cylinder is something that i cant do. Id like to be sure of this rather than, with respect, going by the comment of someone on an internet forum (again, I'm aware you know a lot about this stuff, but, again, id just like confirmation from somewhere external)

Thank you.

 

[JimmyS]

That looks like an oventrop valve. I'm not sure if they are serviceable. Gledhill would have bought it in.

 

[Kayos]

Im sure you know more than me. Ive been looking about, and can find nothing that specifies G3 for vented work?

eg this -

G3 Certificate | Unvented Hot Water Storage Systems

Unvented G3 Certificate course – learn how to install and maintain unvented hot water storage systems (HWSS). Call 0800 345 7492.

www.accesstraininguk.co.uk

Its got "unvented" plastered all over it, as do all the other courses.

When we installed this tank, it was inspected by buildings control, along with the solid fuel appliance connected to it. At the time i was way more interested in meeting Document J specifications, and didn't think that much about the rest of it, but, again, so far as i could ever tell, no special paperwork was required to install a vented thermal store.

You have said otherwise. You are probably right, but, still, id like to be certain. Could you point me towards something that clarifies it for me, please?


In short, someone has told me that swapping a valve on vented cylinder is something that i cant do. Id like to be sure of this rather than, with respect, going by the comment of someone on an internet forum (again, I'm aware you know a lot about this stuff, but, again, id just like confirmation from somewhere external)

Thank you.

It's a thermal store connected to an uncontrolled heat source. It's your house, your choice but I know what I'd do

(Along with sticking to my rule about not replying to plumbing posts)

 

[JimmyS]

Thermostatic Mixing Valve 22mm connections - Plumb Spares Direct

thermostatic mixing valve 22mm connections 448-373-0002

www.plumbsparesdirect.com

 

[julianf]

That looks like an oventrop valve. I'm not sure if they are serviceable. Gledhill would have bought it in.

Thank you. Google spits out the prices of them at, all but identical to, the gledhill price, so I suspect you're right.

...for all the good that does me!

When I realized it was stuffed, I said to my partner "these were £65 years ago, so I bet they're £120 now".

Sadly I was pretty much exactly right : (

 

[julianf]

Thermostatic Mixing Valve 22mm connections - Plumb Spares Direct

thermostatic mixing valve 22mm connections 448-373-0002

www.plumbsparesdirect.com

Ahh, thank you. You did better than me!

 

[JimmyS]

Have a look on ebay check the max temp is ok as some will be for domestic water you want the ht one