We have an unvented Vaillant ecotec 630 system boiler with a Gledhill 200 litre slim tank on the first floor and the boiler in the utility room on ground floor.
Can anyone advise why pump speed (d.019) 2 would be used over speed 1 & what setting would be best for minimum gas usage?
Thanks
Can anyone advise why pump speed (d.019) 2 would be used over speed 1 & what setting would be best for minimum gas usage?
Thanks