Temperature Difference between Radiators and Hot Water

[marks262]

On the gas boiler when the central heating is on it automatically turns on the hot water. Both the radiators and water get hot. However after the central heating is turned off the radiators cool down but the hot water is very hot.

There is a temperature setting on the boiler, which is set to 40c and the heating thermostat to 20c.

Should the boiler temperature be set differently?

Plus should the radiators cool down quickly when there is plenty of hot water in the system?

 

[45yearsagasman]

Now where's my crystal ball that tells me what boiler and system type you have.

 

[D_Hailsham]

On the gas boiler when the central heating is on it automatically turns on the hot water.

You probably have a pumped heating, gravity hot water system.

Which boiler do you have and how many water pipes are connected to it?

Do you have a thermostat on the side of the HW cylinder and do you have any motorized valves (see pics)?

View media item 10596 View media item 5946 View media item 11762

Should the radiators cool down quickly when there is plenty of hot water in the system?

The water circulating in the radiators is not the same water as in the HW cylinder.