Optimise Central Heating Settings?

[Doug99]

My house is a 4 bedroom detached property with recently installed loft insulation, cavity wall insulation and is heated by a WB combi boiler. The central heating is controlled by a room thermostat. If I set my room thermostat at 21C, what is the most effective settings for my boiler?

If the boiler is set 'high', the radiators will get very hot, the thermostat will switch off at 21C but the house temperature will continue to rise above 21C due to the extended time it takes for the radiators to cool down.

If the boiler is set 'low', it will take longer to heat the house, but once 21C has been achieved, I assume it will be more responsive to the rise/fall of the radiators to maintain 21C.

My boiler heating control is calibrated 1-6.

Any comments on the optimimum setting would be appreciated.

VMT

 

[spraggo]

Hi doug99

I suspect that the room stat is faulty, does the room that the stat is fitted in also get up to heat before it switches off?. The boiler should be set to maximum temp to stop it unnecessarily recycling.

Cheers

spraggo

 

[Doug99]

Thanks Spraggo,

My thermostat works ok, and your last comment answers my query. I will set my boiler central heating control to 'max'.

 

[ajrobb]

May I suggest reading the forum's FAQ. I don't know if you have a condensing boiler, these are least efficient at max setting.

 

[mysteryman]

Do you have a simple electro-mechanical room thermostat?

If so, there should be a neutral wire to supply the anticipator heater in the thermostat, which will then give closer control. It is surprising how often this connection is omitted.

If it is a condensing boiler, you can turn the boiler thermostat down in mild weather, as long as it still heats the cylinder satisfactorily.

 

[D_Hailsham]

Do you have a simple electro-mechanical room thermostat?

If so, there should be a neutral wire to supply the anticipator heater in the thermostat, which will then give closer control. It is surprising how often this connection is omitted.

All the anticipator does is reduce the differential between on and off for the thermostat. You will still get the room continuing to warm up after the boiler has gone out. This is because the boiler is pumping out max heat all the time.

If you don't want this problem, you need a thermostat with TPI control such as the Honeywell DT90E (wired) or DT92E (wireless). If you want a programmer which does the same thing, the Honeywell CM900 series is probably the best.