Cylinder stat testing

[efiste2]

I have lowered the temprature on our HW cylinder stat a couple of times and it hasnt made any difference. So I am going to check its working correctly but id like to clarify a couple of things with the experts. (btw we have a pumped C/H and H/W system with a worcester bosch 24i)

1) I think I am right in thinking that once the HW in the cylinder is at a temp set on the stat (roughly) it should turn the boiler off, and the boiler will no longer fire up until the temp of the HW is lower than that set on the stat.........
2)Can I test the above function by having a cylinder full of Cold or luke warm water and turning the boiler on, and then by adjusting the cylinder stat lower and lower in theory it should switch the boiler off.

I hope the above waffle makes a little sense and would appreciate any tips/help, CHEERS!!

 

[kevplumb]

short answer is yes

 

[Ihavenojob]

you could try just the central heating on to see if the hot water valve or 3 port valve is letting by.If this is the case the water would get above the set temperature.

 

[petit_pablo]

Lets start with basics.

Whats the actual temperature of the HW at the tap?

Whats the cylinder stat set at?