Pre heating water before it enters combi

[tripty]

Alpha do the Flowsmart, a combination of thermal store and standard combi, which give excellent flowrates. You can turn off the store in summer if only showers are being used. I think it also has electric store backup too. Best check. Alpha are now pushing this Flowsmart hard.

http://www.alpha-boilers.co.uk/products/?id=7

Using a small vented heat bank can do the same and cheaper too.

Thanks BB! I've been looking for a new system and this appears to be just the thing, now to find a decent plumber

rofl, take BigBurner/Water Systems advice with a very large pinch of salt - he's a nutter.

Some boilers can't modulate at all. They either heat flat out or not at all. If the water comes in at 5C-15C then heating it flat out is fine, but if it comes in at 40C-50C then heating it flat out would make it too hot. The thermostat would detect that and turn the burners off. Then it would get too cold, the thermostat would detect that and turn the burners back on again. Modern boilers will typically have controls to prevent this happening more often than perhaps every minute and your hot water temperature will vary wildly.

Assuming a slightly better boiler that can modulate the burner levels considerably then it may be able to comfortably heat water at 20C to 50C with a steady low level of output, but might not be able to modulate low enough to heat from 40C to 50C. Then you are back to on/off again.

Oh and this post is only two years old.

 

[westeleven]

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[tripty]

Thanks for pointing that out I'm sure you meant to be helpful and not sarcastic

No, I was aiming for sarcasm

 

[mickyg]

westeleven- Don't waste your money on a gas saver the whole cost is stupid once you add it all up. You can get an ATAG A325ec for under £1000 which does the same job all inside the one boiler. The boiler itself is streets ahead of Alpha aswell, better build, bigger modulation ratio on heating, WC and opentherm compatible....and so on and so on..

 

[westeleven]

much appreciated micky. will check that out.