Boiler thermostat question

[JohnMcClane]

I had my boiler serviced today. The engineer offered to turn down the thermostat on the boiler saying it would save money.

I previously set the boiler thermostat to around 70 deg, as the hot water cylinder is set to 65 deg. I always thought if the boiler is set to a lower temperature than the cylinder, then the call for heating when the hot water is turned on will never end.

I asked the engineer about this, and he said it doesn’t work that way.

I had a look in the manual for the boiler, which appears to confirm what I was thinking, that the boiler thermostat should be set higher than the hot water cylinder thermostat.

Who is correct? Do I need to turn the boiler up, or the cylinder to below the boiler (I thought water should be 58 deg or above (>50 for legionella and 58 for hand washing)?), or is it ok to leave it as the engineer has set it?

Or maybe I should alter the hot water schedule knowing the boiler will remain on for the whole time it is scheduled? In which case it would be useful to know how long it takes to heat the water and will depend on usage.

 

[CBW]

Engineer sounds like he’s talking shoite. If you have a boiler temperature of 50 degrees, take off a few for natural heat loss from possibly uninsulated pipes, so possibly 45 degrees, when is the cylinder going to reach 60? Set the boiler back to what is was previously, perhaps 65-70?