Combi boiler temperature differential

[Robert Tyrrell]

2 years ago I installed a Baxi 836 and every year the owners complain about the water temperature. Last year I couldn't find anything wrong but this year there's definitely a low-temperature hot water output.
Although this is usually a warranty claim I'm having difficulty with this as I messed up the warranty registration and they are being slow to sort it out.
My boiler, which is the same, raises the temperature from 10.6 (Cold water supply) to 51.6 (Hot water outlet) but the figures for the other boiler are 10.4(CWS) and 39.4 (HW).
I'd really like to be armed with the correct info before I tackle this with BAXi so if anyone has any ideas as to the cause I'd be grateful for the input.

 

[Chuck]

What are the DHW flow rates? Are they consistent with 36kW being used to heat the water?

 

[John.g]

If both boilers are outputting 36kw then one is flowing 12.6LPM at 51.6C, the other, 17.9LPM at 39.4C. so measure the flowrates and temperatures.

 

[Robert Tyrrell]

Thanks for the info. Flow rates are something that I do know about - just forgot when put on the spot. I'll have to find my flow rate jug now and go back tomorrow as I'm just getting my kit together to take one of my kendo students to another club for training this evening and he's only been taught by me for the last two years