Vaillant EcoTec 831 - How to configure for economy

[ijc060572]

Apologies at start for long post but trying to give as much info as possible,

Home - detached bungalow build 1989, cavity wall insulation, loft had extra in 2008, doubled glazed, 2 bedroom, 1 bathroom.
Size is Width 35 feet, length 32 feet, room height 8ft.

7 Radiators installed 1995 plus 1 towel rail. 5 have TRV valves set at 3.. 2 no valves, lounge where room stat and kitchen.

Boiler replaced in 2011 when had magnaclean added and hotflush and sentinel x100 in system.


Room Stat - Vaillant VRT350F - in analogue mode, in lounge 5ft up wall - receiver in front of boiler RF signal 9. Set to 20c

settings on boiler

D0 - I believe with above if my calcualations right - 12, 15(read pump flicks to 2nd speed at 14.4) and the default 24. please advise best setting
D1 - set to 8
D2 - 20 (default)
d71 - 75 (default)

the d40 and d41 varies as the VRT stat does seem to modulate it.. can be as low as 40 or as high as 75.

at the moment d40 - 75, d41 - 59

I am using approx 75Kwh a day by end of the day. Even when stat reads 20 and stays at that all the hour, the boiler is kicking in and out and uses approx 3.5Kwh during that hour


Any help/advice be much appreciated.. Thanks in advance

 

[ijc060572]

I would add it seems to be constantly on. display on VCF350 says 21 and requires 21 yet boiler always seems to be in S4, it stops then restarts almost instantly ?