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- 21 Dec 2017
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I have a Grant Vortex 36/46. Its derated to about 32kw but even so in normal weather it spends its time bouncing off the boiler stat, burning for about 2 mins, off for 2 mins, burning for 2 mins etc (I've got temperature loggers on the flow and return). Even with a modulating pump the return sometimes creeps up above 55 degrees at which point I presume its dropping out of condensing mode.
I've always thought that it was inevitable and the cost of sorting it (by installing a thermal store?) would be hugely more than the fuel savings. The "Beast from the East" and now the "Mini Beast from the East" have given the boiler the chance to burn continuously all day in full condensing mode (slightly underfired in fact, flow temp maxxed out around 65, boiler stat set at 70). From eyeballing the oil level it doesn't seem to be using that much more oil on "Beast days" than it does normally.
Which make me wonder how much below optimal efficiency short cycling is actually taking me. I asked Grant and they couldn't give me a hard number, does anyone have any figures.
And is there a way of fixing it (or at least making it better) other than putting in a thermal/buffer tank which I'm guesstimating would be 3 grand plus.
Thx
I've always thought that it was inevitable and the cost of sorting it (by installing a thermal store?) would be hugely more than the fuel savings. The "Beast from the East" and now the "Mini Beast from the East" have given the boiler the chance to burn continuously all day in full condensing mode (slightly underfired in fact, flow temp maxxed out around 65, boiler stat set at 70). From eyeballing the oil level it doesn't seem to be using that much more oil on "Beast days" than it does normally.
Which make me wonder how much below optimal efficiency short cycling is actually taking me. I asked Grant and they couldn't give me a hard number, does anyone have any figures.
And is there a way of fixing it (or at least making it better) other than putting in a thermal/buffer tank which I'm guesstimating would be 3 grand plus.
Thx