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Samsung ASHP DHW on - 'Heat' setting off - should central heating radiators still be permanently on?

Air Source Heat Pumps (ASHPs)

Last Post by Horne 2 years ago

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Horne

(@horne)

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Joined: 2 years ago

Posts: 5

Topic starter 01/01/2024 4:34 pm

Hi,

We are new to ASHP tech. We have a Samsung ASHP HT Quiet 8KW - are our radiators (central heating system) supposed to be operating when 'heat' has been turned off on the Gen 6 Samsung control panel and only DHW is set to on in standard mode?

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Horne

(@horne)

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Joined: 2 years ago

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Topic starter 01/01/2024 5:48 pm

P.S. DHW on the Samsung Gen 6 control panel is set to a maximum of 47°c to heat up our immersion water heater.

This post was modified 2 years ago by Horne

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JamesPa

(@jamespa)

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Posts: 2715

01/01/2024 6:16 pm

Posted by: @horne

↑

Hi,

We are new to ASHP tech. We have a Samsung ASHP HT Quiet 8KW - are our radiators (central heating system) supposed to be operating when 'heat' has been turned off on the Gen 6 Samsung control panel and only DHW is set to on in standard mode?

I wouldn't have thought so unless

It's residual heat from when they were supposed to be on or

It's very cold and frost protection has kicked in

Can you give more info please about the symptoms observed and how often under what conditions?

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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Horne

(@horne)

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Topic starter 01/01/2024 11:04 pm

Hi James,

Thank you for replying. Please bear with me as the additional info may be useful. The outside temperature was between 9°c-11°c during both tests

We had been heating our immersion water heater from our AC battery (fed by solar panels) as we were getting up to 24.6 KwH on good days from August to early Oct. The ASHP was installed in early Sept so I asked the installer to set the Samsung DWH to off on the control panel - I had only just got a reasonable understanding of our solar system, AC battery, Harvey and Eddi!

I set the Samsung control panel ‘heat’ temp to 19°c (central heating), DHW setting still off. I was made aware that the radiators weren’t supposed to be hot to touch and that it is best to keep the ASHP running for most of the day.

I did take a reading off the radiators - when the Samsung room stat recorded 19°c - 20°c the rads were around 23°c-25°c - measured with an accurate digital thermometer.

The first time I turned on the ASHP’s DHW (set to 50°c) whilst the central heating was on (‘heat’ temp setting for central heating at 19°c) we noted that the radiators were much hotter than they had been during the past few weeks (barely luke warm at 19°c heat setting and DHW off). I measured the rads to find they were 37.4°c whilst the DHW was operating. The Samsung control panels room temperature went up from 19°c to 24.6°c. The COP reading went from 4/5 down to 2/5.

A few days later I decided to turn off the central heating altogether for a few hours and then turn on the DHW, it was 9°c outside. I set the DHW max temp to 47°c (standard) for the test (see pic). The radiators were stone cold. The immersion was only around 20°c before I activated the DHW. Once again the radiators came on - ‘heat’ setting on the Samsung panel was greyed out - definitely off (see pic). When the Samsung control panel was showing DHW water temp of 40.6°c I measured the radiators with the same thermometer and recorded 34.6°c (image attached).

This post was modified 2 years ago by Horne

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JamesPa

(@jamespa)

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02/01/2024 6:11 pm

@horne

OK that helps. So as I understand it with ch turned off on the Samsung controller, rads get hot when you heat the dhw from the Samsung, but do not get hot when you heat the dhw from another source?

The first thing that comes to mind is a faulty/stuck/incorrectly plumbed/incorrectly wired diverter valve. This valve should ensure that the flow from the hp goes either to the rads or to the dhw tank but never to both. Have a look and a feel of pipe temps and check it's actually a diverter valve not a regular 3 way valve!

There are other possible explanations but that is the simplest.

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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Horne

(@horne)

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Topic starter 02/01/2024 7:57 pm

James,

Thanks. The rads don't get hot when I heat the DHW from another source. I will check the installation - I do remember being told during the installation that one of the valves had to be kept permanently open (reason not given to me) which makes me wonder if this open valve might be the culprit, though my knowledge of plumbing is very basic.

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