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- 24 Jan 2021
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I have a complicated/big system. 3 pumps and a mix of ufh, a few rads and an indirect HWC using a Worcester Conventional
With recent help from some guys on here I’ve got it working almost perfectly....the pump overun “works”, but doesn’t dissipate enough heat quickly enough to actually be of use.
because of multiple pumps I have selected one of the pumps, with a bypass circuit, that via a clever relay comes on whenever the boiler call moves (electrically) to low (off).
This all works electronically. What isn’t that effective is the actual cooling of the boiler by cycling water through it for a couple of minutes when the boiler is no longer called for.
I think this is because there really isn’t much opportunity for the heat to be given up. The flow/return are both 28 copper and highly insulated. The total loop I’d guess is 16-20m in length (from boiler to overrun pump and back). So that’s pretty useless, as is shown by the boiler temperature not decreasing when the overrun comes on.
previously (before the system was completely changed as part of house rebuild) the pump overrun did take the heat away quite nicely, but that flow/return run was problem 3 times as long and not very well insulated.
options I’ve thought of:
With recent help from some guys on here I’ve got it working almost perfectly....the pump overun “works”, but doesn’t dissipate enough heat quickly enough to actually be of use.
because of multiple pumps I have selected one of the pumps, with a bypass circuit, that via a clever relay comes on whenever the boiler call moves (electrically) to low (off).
This all works electronically. What isn’t that effective is the actual cooling of the boiler by cycling water through it for a couple of minutes when the boiler is no longer called for.
I think this is because there really isn’t much opportunity for the heat to be given up. The flow/return are both 28 copper and highly insulated. The total loop I’d guess is 16-20m in length (from boiler to overrun pump and back). So that’s pretty useless, as is shown by the boiler temperature not decreasing when the overrun comes on.
previously (before the system was completely changed as part of house rebuild) the pump overrun did take the heat away quite nicely, but that flow/return run was problem 3 times as long and not very well insulated.
options I’ve thought of:
- remove insulation from flow/return. Seems counterintuitive
- Add to length of current via bypass circuit with more pipe and leave that uninsulated. Seems a hack/looks rubbish
- Add a dedicated device to overrun current design to give up heat. Small rad or is there a specific device, something made of alu with fins etc. A heat sink essentially