UPDATE: I had a conversation with Richard from the Evohome Shop where I bought my kit, who as always, was incredibly helpful. Apart from saying that the ultimate solution is to get a boiler that's correctly sized as this one can't modulate below 6kw, which in many cases is way too much for a single or two rads and the ultimate cause of the problem, he did suggest I balance to a 20 degree drop. I did try, but the rads did not get hot when I went for a 20 degree drop. They did seem to be ok on a 15 degree drop.
The curious thing is that even with a 15 degree differential across all rads, when they were all on simultaneously, I certainly didn't see anything more than about a 5 - 7 degree flow-return differential at most at the boiler (which is a little better than before). I presume this is because hot water is being dumped directly into the return flow via the bypass valve? @mtmcgavock is this why you suggest to close down the bypass valve to 3/4 closed? And if so, while closing the bypass should lower the return flow temperature as it's dumping less hot water directly into the return, won't the increased pump speed of 100% simply narrow the flow-return differential again, causing the behaviour to be similar?
At this point I'm really cursing the genius who decided to install a 38kw boiler where a 24kw at most would have been more than adequate.
The curious thing is that even with a 15 degree differential across all rads, when they were all on simultaneously, I certainly didn't see anything more than about a 5 - 7 degree flow-return differential at most at the boiler (which is a little better than before). I presume this is because hot water is being dumped directly into the return flow via the bypass valve? @mtmcgavock is this why you suggest to close down the bypass valve to 3/4 closed? And if so, while closing the bypass should lower the return flow temperature as it's dumping less hot water directly into the return, won't the increased pump speed of 100% simply narrow the flow-return differential again, causing the behaviour to be similar?
At this point I'm really cursing the genius who decided to install a 38kw boiler where a 24kw at most would have been more than adequate.
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