Worcester bosch 30i

Silverbird65

I have set boiler 65° heat. And 54° water. Is that ok for best condensing thing. As I don't know what is best . The boiler blokes put it on 75° and 60° water which was burning hot. Will still get best energy usage.
Thanks

daveyjp

Set them to whatever you are comfortable with.

Ours are both set at about 50 degrees.  Water is hot enough for baths and showers, heating circuit water is hot enough to reach the set temp.

matelodave

The lower you set it the more economical it will be so try it at 50 for heat and 55 for hot water and see how you get on. Even if it takes a bit longer to heat the house it will use less energy as the boiler will be running in condensing mode for more of the time.

Silverbird65

Thank you. If I set the boiler on 50° for heat we would waiting hrs to reach 19°. The engineers set it at 75° in very cold snap took 4hrs to heat up in morning. I have it 65°. 
Thanks

binao

matelodave said:

The lower you set it the more economical it will be so try it at 50 for heat and 55 for hot water and see how you get on. Even if it takes a bit longer to heat the house it will use less energy as the boiler will be running in condensing mode for more of the time.

@matelodave
What criteria causes a Worcester boiler to flip in and out of the condensing mode?

I'm sorry for the sorta hijack,  it's a bit late to start my own thread.

Silverbird65

I think there has to be 20°difference at least between in flow and out flow. Whatever that means 

matelodave

This is a simple explanation of how a condensing boiler works and it suggests that the return temperature should be at 55 degrees or less otherwise it wont condense. Obviously if the lower the temperature you can get away with, commensurate with reasonable reheat times, then the less energy it will use.

Personally I like to start low and then crank it up a bit to try and get the optimum. You might find that turning the temp down but starting the heating a bit earlier might use less energy than running it it hotter for quicker warm up times. - you'd need to monitor your consumption as well to see what happens.

The principle is much the same as driving a car. Take it gently and you'll get better MPG than if you thrash the life out of it. You'll still get there, it will take a bit longer but you'll use less fuel. The clever bit is working out the optimum speed that gives you acceptable MPG and travel times.

https://www.trustedreviews.com/news/whats-best-temperature-condensing-boiler-set-3649148#:~:text=For the condensing boiler to,dew point is around 55C.

[Deleted User]

Most installed condensing boilers never condense. Even when the magic 55c return flow temperature is reached do not expect high efficiency as this link explains:

https://www.theheatinghub.co.uk/why-our-condensing-boilers-do-not-condense

The problem is that when a new boiler is installed on an old system, the radiators are undersized for running at a lower boiler flow temperature. This will become a much bigger problem when heat pumps are the only option.