Boiler setting.

[Des Jennings]

I have attached images of two boiler dial settings I use on my 3 year old Worcester Bosch boiler. The setting showing a vertical line is what I am using at the moment. The dial set at 45 degrees has not been used for some time. The radiators feel quite hot but the house- a 4 bed semi detached- is taking 6/7 hours to get from 18.5 C to 21.0 C. The temp readings are from a thermostat located in a hallway.
The boiler dial does not give any indication of boiler temp and I'm not sure if there is an accepted position for efficient use, or is it a matter of turning the dial to far right for max output and therefore a faster increase in house temp.

 

[terryplumb]

Turning dial clockwise increases the temperature that the boiler heats water to. Taking several hours to increase temperature a few degrees is more likely to be heat loss ,is the property not well insulated ??

 

[kidgreen61]

It sounds as though either your rads are terribly undersized, or all your doors and windows are open?
Where is all that heat from your hot rads going?

 

[Des Jennings]

Thanks for your replies. I wonder if my impression of a hot radiator is the same as everyone else a by turning up the dial the heat output will increase. Also, what is the expected rise in house temp/hour? The house is 20 years old so is well insulated.
I have attached a photo of the hall radiator to give an example of size.
The house only dropped about 3 degrees during the last couple of cold nights, it's getting the temperature back up that is the issue.

 

[flameport]

Turn the dial to the maximum, and switch the heating on. Set any room thermostat(s) to maximum as well.
Does the boiler stay on continuously for 10s of minutes, or it it switching on/off/on/off every minute or so?

How long before the radiators start to feel warm?
How long before the radiators are too hot to touch?
Do all the radiators heat up at the same time, or do some take much longer?

 

[CBW]

What speed is the pump set to? Is this on an s plan or y plan? Are you calling for heating and hot water together or separate?

 

[Des Jennings]

Turn the dial to the maximum, and switch the heating on. Set any room thermostat(s) to maximum as well.
Does the boiler stay on continuously for 10s of minutes, or it it switching on/off/on/off every minute or so?

How long before the radiators start to feel warm?
How long before the radiators are too hot to touch?
Do all the radiators heat up at the same time, or do some take much longer?

Hi. The boiler stays on continuously until the temp set on the ' smart ' thermostat is reached. Today I set the temp to 21C. The boiler was switched on at 10.10 this morning when the temp was 18.5C. Three hours later at 13.10 the temp was 20.8C.
I moved the boiler dial from the half way point to in between half way and max compared with yesterday. The radiators were certainly hotter than being at the half way point. There are a number of small radiators in the house without thermostats which heat up quickly but some of the larger radiators, although all bled, take longer to heat up. The large radiators that do heat up quickly take about 15-20 mins, those that are slower to heat up take up to 30/40 mins.

 

[ianmcd]

You have a smart thermostat, set the boiler thermostat to max and let the smart thermostat do its job

 

[Des Jennings]

What speed is the pump set to? Is this on an s plan or y plan? Are you calling for heating and hot water together or separate?

Hi. The pump is set to max and the system is on an S plan. When I have been checking the system to see how long a particular temp takes to reach, I have been calling for heat only.

 

[Des Jennings]

You have a smart thermostat, set the boiler thermostat to max and let the smart thermostat do its job

Well , the thermostat might be called 'smart' but I use it just like you would an analogue: adjust the set temperature and monitor the result in terms of heating the house. The app for the thermostat produces graphs which are useful in terms of long term assessment as well. My question has really related to having the boiler output set as low as possible but getting the optimum output as quickly as possible, something I've felt is not happening at the moment.

 

[sxturbo]

Well , the thermostat might be called 'smart' but I use it just like you would an analogue: adjust the set temperature and monitor the result in terms of heating the house. The app for the thermostat produces graphs which are useful in terms of long term assessment as well. My question has really related to having the boiler output set as low as possible but getting the optimum output as quickly as possible, something I've felt is not happening at the moment.

you wont be able to get a satisfactory warm up time with the setup you are using.

How it should work is that the water is heated to its max say 65/70 degrees to get the house warm quickly, then when its to temp the temp reduces to a level to keep the house at a constant temperature this is what you get with opentherm or the proprietary bosch smart system.. you cant really get this with an on/off stat.

 

[Des Jennings]

you wont be able to get a satisfactory warm up time with the setup you are using.

How it should work is that the water is heated to its max say 65/70 degrees to get the house warm quickly, then when its to temp the temp reduces to a level to keep the house at a constant temperature this is what you get with opentherm or the proprietary bosch smart system.. you cant really get this with an on/off stat.

What happens at the moment is, in the morning the house is heated from approx 18C to 21C in about 4 hours. At 21.2C the boiler switches off. The house temp then reduces to 20.8 in approx 2.5 hours, then the boiler switches on again and the cycle repeats if I want it to.This is with the boiler dial not set at maximum.

 

[sxturbo]

What happens at the moment is, in the morning the house is heated from approx 18C to 21C in about 4 hours. At 21.2C the boiler switches off. The house temp then reduces to 20.8 in approx 2.5 hours, then the boiler switches on again and the cycle repeats if I want it to. This is with the boiler dial not set at maximum.

4 hours to heat the house is too long,

if you set the boiler right you could have the house to temp in 30 minutes (maybe even less) to an hour.

depending on what stat you have, some learn the room/house heating times and adjust the on/off cycles accordingly, but the heating circuit temp needs to be set correctly.

turn the boiler knob to almost max

your house is obviously reasonably insulated as it takes a few hour to drop a degree.

also sounds like you need to balance your radiators aswell -

 

[Des Jennings]

4 hours to heat the house is too long,

if you set the boiler right you could have the house to temp in 30 minutes (maybe even less) to an hour.

depending on what stat you have, some learn the room/house heating times and adjust the on/off cycles accordingly, but the heating circuit temp needs to be set correctly.

turn the boiler knob to almost max

your house is obviously reasonably insulated as it takes a few hour to drop a degree.

also sounds like you need to balance your radiators aswell -

Thanks for your help.

4 hours to heat the house is too long,

if you set the boiler right you could have the house to temp in 30 minutes (maybe even less) to an hour.

depending on what stat you have, some learn the room/house heating times and adjust the on/off cycles accordingly, but the heating circuit temp needs to be set correctly.

turn the boiler knob to almost max

your house is obviously reasonably insulated as it takes a few hour to drop a degree.

also sounds like you need to balance your radiators aswell -

Thanks. I adjusted the boiler dial this morning to a new position ( see attached). The CH was switched on at 10.00 with the hall thermostat reading 18.5C . The radiators certainly got hot , eventually too hot to touch. The boiler switched off at 21.2 C at 13.00. So the the temp was raised by 2.7C in 3 hours, still nowhere near your suggested 30mins to an hour but better than when using lower boiler dial positions.

 

[Harry Bloomfield]

Set the boiler to maximum when ever you need to raise the house temperature quickly, then turn it down once it has got up to the comfort temperature. Experience will help you determine how much you can turn it down. The better more modern control systems will be able to do this automatically for you...

They know how high to set the boiler stat, in order to hit your set room temperature within a reasonable time, then ramp the boiler down so as not to over shoot.