Issue with automatic bypass?

[Stuckinarut]

I've had a look through some pages relating to automatic bypass valves, but a lot of them cover installing one and overheating, so mine might be a different issue.

I understand what the valve is for, however I'm wondering if it's stuck open? When I have the heating on or dhw the outlet pipe from the abv is red hot to touch, now I know this shouldn't be the case.

My hot water also seems quite hot to touch, so if this abv is broken, could it also send the pump overrun water back through the return of the cylinder?

Thanks

 

[Johntheo5]

It should only send water back via the cylinder to the boiler on pump overrun or very low flowrates if rad TRVs start throttling down.
What make is the ABV and what is its indexed setting at?

 

[Stuckinarut]

No idea on make, couldn't see one. It has a thin red cap, everything else was Myson, so maybe Myson? I think it's 0.2 the reading.

 

[Johntheo5]

Turn the red cap slowly clockwise to setting 0.25/0.3, see if the pipe cools down with system running normally and gets hot on pump over run if not just make very small adjustments until it does.

 

[Stuckinarut]

Ok, I'll try this when I get home, thanks

 

[Stuckinarut]

Just done an internet search and found this which looks similar or the same as mine