Flow and return temp at the boiler 5c even when rads balanced

[Johnytuono]

All rads balanced to 12-15C difference, yet no matter what I do (even lowering the pump speed), when I look at the menu system on my WB Si compact 30 it only shows a 5C difference at the boiler !
Thought anyone?
Thanks

 

[Johntheo5]

Does the boiler display flow and return temperatures or are you measuring the return (and flow) at the boiler.
The MIs for this boiler show a ABV which may be bypassing even with a very low pump head so even though the flow/return at the boiler may have a dT of 10C or higher, this may only be 5C in the boiler.

 

[Johnytuono]

Reading off the menu display John, would this not be fairly accurate ?

 

[Johnytuono]

What I mean is, am I really only getting 5c or is the way it reads it flawed?

 

[Johntheo5]

It certainly will/should be reading accurately but that doesn't mean that the actual rads return are at the same temperature IF the ABV is bypassing, can you measure or even feel the return before it enters the boiler to get some idea of the actual temperature, obviously if the ABV isn't bypassing then that boiler dT is the same as the rads dT.

You may also have a external bypass so check for one.

 

[Johnytuono]

I know I haven’t an external one. I will have a measure tomorrow John. If it is the ABV bypassing, is it adjustable via a Gas Safe person?

 

[Johntheo5]

If your boiler is the one shown in these MIs then it doesn't mention any adjustment, it just looks like a simple, maybe spring loaded bypass, depending on what your measurements are tomorrow then maybe worth giving WB a tinkle.