On Mon, 3 Jul 2006 17:32:47 +0100, Anode wrote
(in article ):

Is there some setup of a wet central heating system that will let radiators
be warm most of the time, and not cycling between over-hot and over-cold, as
mine are now?



At present I have a 15years old gas fired non-modulating boiler with a
pumped, vented, system, controlled by a wall thermostat. The controls on
this system will not avoid radiators that are either on and far too hot, or
off.



Thus the radiators cycle between being much hotter than is needed for just
compensating for heat losses from the rooms, producing unpleasantly hot air
around the radiators, and then cycling to a period of being colder than they
need to be.



Is there any setup that would give me the necessary heat output but in a
more balanced way, so the radiators will be on for longer but at an
appropriately lower temperature, with the period in the cycle when the
radiators are off being correspondingly much reduced?



As the age of the boiler is such that it could well be replaced, what kind
of setup should I be considering?



I have a MAN Micromat boiler. It has a number of features which achieve what
you are describing:

- Burner modulates from 3-30kW

- Pump modulates continuously from 20-100% of output

- External temperature sensor is used in calculation of heat requirement.

- Detection of flow and return temperatures.

The result of this is that during the period from autumn to spring, the
boiler runs almost continuously at low output with radiator flow temperatures
in the region of 40-45 degrees, getting hotter only when the outside
temperature falls to a point that more heat output is required.

This is a high quality German designed and manufactured product. A similar
range is made by Viessmann.

Expect to pay around £1500 for such a boiler.