Another thing to consider is that with the original firmware you could ADD hot water priority with a very simple wiring change (interconnecting the hot water and heating relay contacts) but with hot water priority implemented in software you cannot REMOVE it by making a wiring change.
So adding it in software without an off setting takes away flexibility that was previously there in the system.
Last edited by DBMandrake; 20th April 2020 at 03:02 PM.
It appears to me that someone had a cunning plan to overcome a problem, with what I suspect is a minority of boilers/installations, without properly considering the implications for the majority of current installations. As those who need it have a work around, the obvious solution, if it is to late to make it optional, is to drop it from this release and introduce it properly in the next release with an option.
In my case I have a bypass rad in the bathroom but in the summer with no heat on when the HW Zone valve opened and boiler fired the bypass rad was also getting hot and overheating the bathroom
I put a normally open zone valve on heating circuit wired in parallel with the HW valve so when Hot water valve is open CH Valve Closes this works good and the CH valve is only energised during HW cycles other times it is always open I suppose its a form of HW Priorty
The replacement valve arrived yesterday so I got the head swapped over and wired back in. Two things I noticed since then, both expected:
1) No more rooms going over temperature during hot water reheat. Yay!
2) When TRV's demand full heat the radiators are getting a LOT hotter than they were when I had the CH valve manually latched on the fill position as a workaround.
I've mentioned this in other threads before but the fill position on two port valves only opens the valve around 1/4 to 1/2 way and there is a lot of flow restriction vs being fully opened by the motor. Enough flow to fill and bleed a system, but not enough to get full flow and full performance.
The difference in panel temps on some of my larger radiators between a manually latched and powered open CH valve is really obvious!
Last edited by DBMandrake; 24th April 2020 at 11:02 PM.
Be interesting to see how long your new head lasts for. As I said in my earlier post been having a lot of issues with the Honeywell valves failing of recent. One where it got stuck open on an Unvented cylinder.
Yes it's amazing how much difference it makes. Suppose you can see this on the valve on the backplate before you fit them, just goes to show that latching the valve open isn't ideal.
Have you found a motor to replace the one in the old valve yet?
Sorry Andy, missed your post.
I do not think it would be worth looking at my history for this. For most of the year, a large proportion of my water heating comes from Solar. My requirement for HW also varies dependant on number of occupants/visitors etc. For this reason I tend to use a lot of manual boosts rather than timed settings. In any case it is not just the time taken to heat a full tank of hot water.
The worst time is when it is very cold and the solar panels are covered with snow, thankfully not very often, but I would not want my relatively small radiators to be cold while the hot water is heated.
At other times the water is warm but needs a boost before taking a showers or baths. We do not follow any set pattern for this so usually turn the heating on in the bathroom and give the hot water a boost just before and after use. If the heating and HW had to operate sequentially this would require a longer time and more planning. If the whole family were staying over, bath/shower time could result in a long period without heating.
If we had been away from home for a few days in the winter, we would have a cold house and no hot water. With HW priority it would be an unacceptably time before the heating kicked in. Unfortunately for your analysis this has not happen recently.
Speaking of Boost, has anyone else noticed that in the Beta you have to confirm the Boost before the HW BDR91 clicks in. In the previous firmware, if I remember right, it wouldn't wait for you to click the Green Tick. So Boost now is a 2 click feature.