I have just had a Glow Worm engineer to look at ours because our hot water was only warm (35c). He said this is a design of the boiler as it heats the water to 34c above the outside temp. He slowed the water rate down to 10ltr/min for the default 12ltr/min and it’s made a small difference. Apparently the model above 35cx would do the job better!
Paid British Gas a small fortune to for this and I’m in the process of complaining.
James W
January 2010