My Viessman boiler journey

[marshian]

Well I have a new HW tank to fit soon but I've been trying to optimise the HW a little more - Average consumption is 4kWh per day to do the water heating for two people occupancy.

 

Flow temp is typically 66 Deg C return temp peaks at 61 Deg C, 115 Litre tank and 30 Min Cycle with the tank ending up at 52 Deg C (I've tried the lower and slower approach and to be honest it actually uses more gas but I think that's because of overshooting the target temp when I did it)

 

However because of the X plan set up it does mean even in the summer I put a slug of 68 deg water into the rads straight after the HW cycle is finished. In winter no issues - it helps make up for the HW cycle time out of CH - summer it contribute to heat gain in the house......

 

I decided to do an experiment..........

 

If I run the HW for 30 mins and ten kill the boiler and continue to circulate the HW system with no boiler activity I can get an increase in the tank temp of 2 deg C and the water hitting the rads is down to 50 deg C

 

I'm now thinking about putting a delay timer on the HW valve closing 10 mins after HW cycle is completed to extract the last bit of energy out of boiler and circuit

 

Mad idea?