I had a new Vaillant Eco Tech Plus 630 boiler fitted in December 12 and the heating engineer set the flow temp at 60c from the boiler. I have mixing valves fitted to each UFH manifold.
I posted various queries about the flow temp / operating time etc here having had the boiler fitted see....
//www.diynot.com/forums/plumbing/ufh-new-boiler.348894/
I received some excellent advice thank you all.
Last winter 2013/14 i decided to lower the boiler flow temp to 55c. I ran the system 24/7 and the house was usually comfortably warm - only on the coldest days did we use our open fire. I have just renewed my gas / electricity deal and my gas usage was a little over 25% lower over the past 12 months. I accept that we had a milder winter last year and this would have affected demand / gas usage. However I have lowered my utility costs from £130.00 pcm to £85.00 pcm for the coming year - new deal same supplier.
Spoke with my HE a couple of weeks ago when he serviced the boiler and he maintains that an increased flow temp of 66c (higher than the previous 60%) is the most efficient operating temperature for the boiler and the system, the DHW is supplied from the same flow. The system, which was fitted by someone else, has the DHW supplied from the same UFH flow from the boiler. The DHW is now much hotter!!!
I keep an eye on my gas usage and at the current 66c setting i am using consuming 80% of the gas I was using in the coldest period of last winter and it is very mild at the moment.
I dont have a weather compensating unit fitted to the boiler but I guess that it may be cheap if i manually adjust the flow temperature to reflect likely outside temperatures. I don't like going against the advice of the professional but...................
I posted various queries about the flow temp / operating time etc here having had the boiler fitted see....
//www.diynot.com/forums/plumbing/ufh-new-boiler.348894/
I received some excellent advice thank you all.
Last winter 2013/14 i decided to lower the boiler flow temp to 55c. I ran the system 24/7 and the house was usually comfortably warm - only on the coldest days did we use our open fire. I have just renewed my gas / electricity deal and my gas usage was a little over 25% lower over the past 12 months. I accept that we had a milder winter last year and this would have affected demand / gas usage. However I have lowered my utility costs from £130.00 pcm to £85.00 pcm for the coming year - new deal same supplier.
Spoke with my HE a couple of weeks ago when he serviced the boiler and he maintains that an increased flow temp of 66c (higher than the previous 60%) is the most efficient operating temperature for the boiler and the system, the DHW is supplied from the same flow. The system, which was fitted by someone else, has the DHW supplied from the same UFH flow from the boiler. The DHW is now much hotter!!!
I keep an eye on my gas usage and at the current 66c setting i am using consuming 80% of the gas I was using in the coldest period of last winter and it is very mild at the moment.
I dont have a weather compensating unit fitted to the boiler but I guess that it may be cheap if i manually adjust the flow temperature to reflect likely outside temperatures. I don't like going against the advice of the professional but...................