CH plumbing - what's this?

[chris French]

Been investigating the CH system (pretty old pumped CH/Gravity HW) before I repair/upgrade it.

This device is in the CH flow pipe:

For reference the pipe it is 10.5/l 86 C (as in centigrade)

What is it?

[Doctor Drivel]

Could be:

- a non-return valve to prevent gravity circulation into the CH circuit. Or;

- a high temp limit to prevent rads overheating and causing burns.

With modern controls it is redundant now.

[s--p--o--n--i--x]

I'd hazard a guess that it's a non-return valve as my CH system has a weir (But different) valve on it.

It looks like it's a normal tap/valve type base but with a different head on it. I recon there'll be a washer/spring type thingumajig in there that lets the water through one way but not the other.

sponix