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Ecodan high pressure at 3 bar

Air Source Heat Pumps (ASHPs)

Last Post by @sand 9 months ago

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@sand

(@sand)

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Topic starter 13/11/2024 7:38 pm

We have a Mitsubishi Ecodan with UFH downstairs and radiators upstairs. The pressure at the water tank is 3 bar.

I have lowered this by bleeding water from the radiators to 2 bar as indicated by the fixed red marker on the pressure gauge.

This has gone back up to 3 bar and there is water coming from all the radiator bleed valves when opened so no air in them it seems.

We have had 2 new towel rails replacing cheap old ones. Not sure if this has anything to do with it.

Any advice on how I can resolve this issue and what might be causing it?

Andy

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dorkypark

(@dorkypark)

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13/11/2024 7:55 pm

Something similar happened to me once with a gas system boiler. The filling loop hadn't been closed properly and it was pushing up the pressure over time. You might want to check that.

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JamesPa

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13/11/2024 8:25 pm

Posted by: @dorkypark

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The filling loop hadn't been closed properly and it was pushing up the pressure over time. You might want to check that.

That's a good reason to disconnect the filling loop when not in use, in the way that it is designed for!

4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.

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@sand

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Topic starter 13/11/2024 8:25 pm

Hi thanks for that, I'm not sure if I'm correct but I seem to remember having to open a valve to add pressure to the system. Would this be the valve that you mean? It was fully open and I've now closed it.

This post was modified 9 months ago by Mars

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@sand

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Topic starter 13/11/2024 8:31 pm

This is the valve I have closed is that correct, will I need to bleed rads again?

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dorkypark

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13/11/2024 9:00 pm

Yes, you would need to reduce the pressure to the correct value for your system (usually 1 to 1.5 bar when cold).

And as @jamespa says, disconnecting the filling loop when not used is the correct thing to do.

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@sand

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Topic starter 13/11/2024 9:05 pm

Thanks, will do.

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Toodles

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14/11/2024 1:19 pm

@sand I far as I am aware, all systems have two of these valves (one on each side of the mains feed to the red tank; these should both be shut off after any adjustment to pressure. (I may be wrong but all systems I have come across have the two valves and plumbers have told me they should both be shut after adjustments are complete.) Nervously, Toodles.

Toodles, he heats his home with cold draughts and cooks his food with magnets.

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JamesPa

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14/11/2024 1:55 pm

Posted by: @toodles

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@sand I far as I am aware, all systems have two of these valves (one on each side of the mains feed to the red tank; these should both be shut off after any adjustment to pressure. (I may be wrong but all systems I have come across have the two valves and plumbers have told me they should both be shut after adjustments are complete.) Nervously, Toodles.

You are correct, but they also come with thumb-turn fittings so they can be disconnected easily. On mine at least its necessary to do this to be sure that the shut off valve is truly shut off.

4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.

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