Central heating boiler & 'weather compensation'

[BolshieBastard]

Last week, had our year old boiler upgraded to weather and load compensation. The idea behind this is supposedly to make the boiler operate as efficiently as possible so it 'condenses' to the highest degree, uses less gas and runs at a lower overall temperature, by comparing the outside temperature with the demand for heat in the house.

By looking at the boiler stats, it's easy to see that the boiler now runs at around 54 degrees instead of 70. But, it takes hours to increase the temperature in the house to the 'target' temperature which, to be fair, it maintains rather than overshooting the target for traditional CH systems, cools down quickly then fires up and overshoots the target again, rinse and repeat. SWMBO likes it to be about 21 as this helps with her arthritis.

According to gas bills for this time last year, with the same boiler but no weather \ load compensation, we were using about 29kw of gas a day. To date, reading the stats from the boiler, we're only using 21kw of gas a day so seems to be making a saving.

Anyone else had weather compensation installed \ enabled on their boiler and how are you finding it?

Does it take 4 or 5 hours to reach your preferred temperature? Im going to give it another week or two before considering getting the engineer back and asking him to tweak the heating curve if he can to address the time it takes to get to the target temp.

[sadkingbilly]

did you bleed the radiators???

[DoctorStrangelove]

Or put that silvery insulation stuff behind said radiators?

Is this some sort of three term control algorithm?

Great fun optimising one of those. .

[BolshieBastard]

did you bleed the radiators???

Only people with non pressurised CH systems need to 'bleed the radiators,' dear boy!

[Protagoras]

Anyone else had weather compensation installed \ enabled on their boiler and how are you finding it?

Yes, it takes a relatively long time to reach the target temperature.

There's a 'smart' mode on mine where rather than having the system set a new target temperature from a given time, it can be set to achieve the target temperature at the given time. I've not tried this since only had the new boiler for a few weeks.

[BolshieBastard]

Yes, it takes a relatively long time to reach the target temperature.

There's a 'smart' mode on mine where rather than having the system set a new target temperature from a given time, it can be set to achieve the target temperature at the given time. I've not tried this since only had the new boiler for a few weeks.

Yes, we're finding it taking too long to get to target temperature as well. The engineer is coming back next week to tweak the 'curve' so it takes more notice of the internal thermostat and reaches target a little quicker. Once it reaches target, it maintains it far better than the old fashioned 'saw tooth' max heat, switch off, temperature drop off, max heat, switch off etc.

We seem to be using about 18% less gas according to the metrics as well.

[WTFH]

Only people with non pressurised CH systems need to 'bleed the radiators,' dear boy!

Oh dear.
Did you assume that?

With pressurised systems you need to check the pressure is stable at the boiler (probably around 1-1.5bar, which will be something else in measures that I wasn't educated in). If the pressure drops, then top it up, there will be two valves in the boiler which will allow you to do that.

You'll also want to check the radiators at least annually and bleed if required. If you notice that some are cooler than others at the top, then bleed them. Once you bleed a radiator, then go back and top up the system at the boiler.
One of the good things about pressurised systems is that they tend to reach a stage where it's only one radiator on each floor that needs bleeding, although vertical radiators are a law unto themselves.

[NotAllThere]

I have underfloor heating. Still needs bleeding once a year.

[sadkingbilly]

Only people with non pressurised CH systems need to 'bleed the radiators,' dear boy!

oh, dear!- so sorry oh great one!
but you're talking utter bolloks, with all due respect.

[woody1]

According to gas bills for this time last year, with the same boiler but no weather \ load compensation, we were using about 29kw of gas a day. To date, reading the stats from the boiler, we're only using 21kw of gas a day so seems to be making a saving.

How much of that saving is down to the fact that the house is spending fewer hours per day up to temperature?