Replacing thermostatic head sensor

[DIY_Amateur]

Hi - I'm pretty sure the thermostatic head (with capillary sensor) on my UFH manifold is knackered. 

 

I can get a replacement and the head will just screw onto the valve body but accessing the current sensor and having room to remove it is going to be a pain. 

 

Two questions:

1) The sensor is held in with a grub screw so I assume it's not actually immersed in water inside the manifold (Uponor Vario B, maybe cocooned in a sleeve?) Is that right/likely and if I was able to remove the grub screw and get the sensor out would I need to drain the manifold first?

2) If I really can't get the old sensor out can I attach the sensor directly to the flow side of the manifold with some cable ties and maybe some aluminium tape/insulation - would this work do you think?

 

There are surprisingly few pictures/video of this job so I appreciate any knowledge of what it involves.

 

Thank you

 

 

 

 

 

[PeterW]

Sensor will slide out of its pocket. Just remove the link grub screw and twist it a little to break any potential corrosion. They are dry pockets so no water should escape. 

[DIY_Amateur]

Hi Peter- that's very helpful thank you

 

The sensor is pressed against the wall so would need to slide 10cm or so into the wall! I'm tempted to see if I can find a way to carve a hole for it to slide into but if not it plan (2) - any thoughts on whether strapping it to the manifold would work adequately?

 

[PeterW]

You’d need to work out how to get the new one in too ..! I do sometimes wonder what installers are thinking when they install these ..!!

[Nickfromwales]

Drain down and disassemble. Do the job properly   

[DIY_Amateur]

Thanks Nick - I went for plan (3) and created a hole in the wall that I could slide the sensor into and remove it, so I've saved having to drain down and hopefully the new part will fix things.

 

Thanks for the advice

[ProDave]

16 hours ago, PeterW said:

You’d need to work out how to get the new one in too ..! I do sometimes wonder what installers are thinking when they install these ..!!

Had the same problem with a HW tank and immersion heater,  I had to cut a hole in a wall to get the old immersion heater out and a new one in.  People just don't think.