DHW SETTINGS on Gas Boiler

[Jon999]

Why are there options for setting time periods for DHW?

If set for 24hours, ie 24/7 won’t the boiler simply turn on .. on demand?…no need for time periods!

What am I not seeing?

 

[Deleted member 120897]

What we’re not seeing is what type of boiler/system you have

 

[Jon999]

What we’re not seeing is what type of boiler/system you have

Sorry….I thought all CH systems were generally the same!
NG - Worcester GREENSTAR 8000 life CH-15Rads/DHW

 

[Chuck]

If you have the DHW on 24/7 the boiler will try to keep the tank at 60°C all the time which means the return temperature from the heat exchanger in the tank will be at 60°C, which is inefficient, and there will be unnecessary wear and tear on the zone valve and boiler. Also, having the boiler cycling on and off can be annoying to occupants, particularly at night, due to noise.

 

[Jon999]

If you have the DHW on 24/7 the boiler will try to keep the tank at 60°C all the time which means the return temperature from the heat exchanger in the tank will be at 60°C, which is inefficient, and there will be unnecessary wear and tear on the zone valve and boiler. Also, having the boiler cycling on and off can be annoying to occupants, particularly at night, due to noise.

If DHW is programmed for set periods of on and off and a demand for dhw is made during an off period presumably there will be a delay in obtaining hot water, whereas if this happened during on period, hot water demand would be effectively instant!

 

[Chuck]

If DHW is programmed for set periods of on and off and a demand for dhw is made during an off period presumably there will be a delay in obtaining hot water, whereas if this happened during on period, hot water demand would be effectively instant!

Sorry, my reply was written with a system boiler and external DHW store in mind. If you have a combi and are talking about scheduling the 'preheat' function then things are a bit less extreme but you are still trading off energy use against convenience and potentially wasted water.