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jon
@jon
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Joined: Sep 29, 2023
Last seen: Sep 13, 2026
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Topics: 1 / Replies: 11
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RE: Problems with sizing a replacement for a Viessmann Vitocal 200-S

@judith Thanks very much for this! My room by room calculation, done on my own spreadsheet, comes out at about 18 kW. I've also found the original Nu-...

2 weeks ago
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Air Source Heat Pumps (ASHPs)
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RE: Problems with sizing a replacement for a Viessmann Vitocal 200-S

@cathoderay Yes, it does look much better, thanks for suggesting it. I do now log gas consumption for DHW additionally to the total consumption, so it...

3 weeks ago
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Air Source Heat Pumps (ASHPs)
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RE: Problems with sizing a replacement for a Viessmann Vitocal 200-S

@cathoderay I've deblobbed the chart and extrapolated. Also gas usage for DHW was a crazily high 39 kWh per day mainly because the circulating pump ...

3 weeks ago
Forum
Air Source Heat Pumps (ASHPs)
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RE: Problems with sizing a replacement for a Viessmann Vitocal 200-S

The Vitotronic 200 WO1C control unit manual can be downloaded here (link will download the PDF manual): Viessmann Manual The relevant descriptions a...

3 weeks ago
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Air Source Heat Pumps (ASHPs)
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RE: Problems with sizing a replacement for a Viessmann Vitocal 200-S

@cathoderay @transparent @jamespa I've got data from my outside temperature sensors (mounted on a shaded, north facing wall) so I might try again usin...

4 weeks ago
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Air Source Heat Pumps (ASHPs)
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RE: Problems with sizing a replacement for a Viessmann Vitocal 200-S

@jamespa Thanks for this. Let me address the hot water point first. The basement plant room has two Viesmann Vitocell 300 hot water cylinders, each wi...

4 weeks ago
Forum
Air Source Heat Pumps (ASHPs)
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RE: Problems with sizing a replacement for a Viessmann Vitocal 200-S

@transparent Sorry for the silence, I'm working today but will reply properly this evening (yes, ERA5 was Claude's choice, but I can go back to degree...

4 weeks ago
Forum
Air Source Heat Pumps (ASHPs)
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RE: Problems with sizing a replacement for a Viessmann Vitocal 200-S

@jamespa @transparent Sorry about that. Here are the charts, hopefully these are a bit easier to follow than the text:

4 weeks ago
Forum
Air Source Heat Pumps (ASHPs)
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RE: Problems with sizing a replacement for a Viessmann Vitocal 200-S

@bobflux It was originally, but now both are using the same heating curve, with the TRVs fully open.

4 weeks ago
Forum
Air Source Heat Pumps (ASHPs)
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RE: Problems with sizing a replacement for a Viessmann Vitocal 200-S

@jamespa I have revised my figure downwards as a result of your scrutiny, so thank you! The challenge about wanting to see the raw plots, and the ques...

4 weeks ago
Forum
Air Source Heat Pumps (ASHPs)
Topic
Problems with sizing a replacement for a Viessmann Vitocal 200-S
4 weeks ago
Forum
Air Source Heat Pumps (ASHPs)
Replies: 37
Views: 788
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RE: Say hello and introduce yourself

Hello everyone. I've recently found this forum and thought I would detail my setup as I've spent a lot of time on it over the years. My house was ne...

3 years ago
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