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Samsung gen 6 - how to manually turn on/off immersion (booster)

Air Source Heat Pumps (ASHPs)

Last Post by Old_Scientist 1 year ago

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Old_Scientist

(@old_scientist)

Honorable Member Member

Joined: 1 year ago

Posts: 250

Topic starter 16/06/2024 9:17 am

Hi all,

New to the forums - I've just had a Samsung gen6 12kW ASHP installed, and initial impressions are good - install seems good and it's running well.

One thing I can't figure out is a quick/easy way to manually (and/or schedule) the immersion to come on/off.

We are on Octopus Agile tariff, so occasionally get very cheap or free electricity slots. I've disabled the scheduled legionella cycle (we empty and reheat the tank twice daily), and try to schedule DHW reheats during cheaper periods. But I'd like to be able to manually turn on/off the immersion to take advantage of cheap/free pricing slots to manually manage heating the DHW tank to higher temps when it's cheap/free (as a cheap/free store of energy and manual legionella protection). Is there an easy way to turn on/off the immersion?

In the control panel schedule, I use Standard DHW to schedule the overnight reheat, and it reheats in around 20-25mins depending on starting/ambient temps (Max Operating Time (3025) and Delay Time (3032) both set to 60min to prevent immersion from kicking in on normal DHW reheat cycle). I understand the Power option uses the immersion - does the Power option use the immersion for the whole cycle? If so, I could use this, but not sure how to then heat above my max DHW temp setting of 50C (FSV 3021) or does 3021 limit only apply to the ASHP, not the immersion?

I'd like to understand exactly how the legionella (disinfection) cycle operates? I have a set point of 47C for DHW, with a max temp set to 50C (FSV 3021). Does the legionella programme heat to 50C using the ASHP and then use the immersion to boost this to 60C (or whatever it's set at in FSV 3044), or does the whole cycle use the immersion (booster) heater?

Thanks in advance,

This topic was modified 1 year ago by Mars

Samsung 12kW gen6 ASHP with 50L volumiser and all new large radiators. 7.2kWp solar (south facing), Tesla PW3 (13.5kW)
Solar generation completely offsets ASHP usage annually. We no longer burn ~1600L of kerosene annually.

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EcoBaker

(@ecobaker)

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Joined: 2 years ago

Posts: 44

17/06/2024 6:29 pm

@old_scientist HI OS, yeah you're right using the power mode or forced mode the delay timer for the immersion heater will be neglected and will switch on straight away.

You can use the over shoot setting #3033 and increase to 4, so it will heat 4 degrees over your set temperature.

So I think you can set a very long delay for the booster heater, when running the DWH on standard mode, that way the booster will almost never turn on. Then when you want to do a manual heat up, use the power/forced mode to fire up the immersion heater straight away.

This post was modified 1 year ago by EcoBaker

Samsung Gen6 8kw ASHP in a two bed victorian mid terrace.

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Old_Scientist

(@old_scientist)

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Joined: 1 year ago

Posts: 250

Topic starter 17/06/2024 7:53 pm

@ecobaker Thanks. Hopefully we may have some cheap pricing slots on Agile this weekend, so I will be able to have a play and observe how these settings behave in practice.

I have already set a long Delay Time (3032) of 60mins to prevent the immersion kicking in in normal operation, but have not tried Power or Forced mode yet to see how they behave. I'll check #3033, but I suspect it's at the default value of zero.

Not sure how I can use this to get to higher temps though (for manual legionella cycle), as the max temp is 55C, and the max overshoot is 4C, giving a combined max achievable temp of 59C?

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EcoBaker

(@ecobaker)

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Joined: 2 years ago

Posts: 44

17/06/2024 8:31 pm

@old_scientist My one thought is that if you’re getting 100% efficient very cheap hot water, is that still more expensive than 400% efficient heat at your standard rate?

How cheap are the cheap rates? It might not actually be worth doing because of the reduced efficiency.

Samsung Gen6 8kw ASHP in a two bed victorian mid terrace.

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Old_Scientist

(@old_scientist)

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Joined: 1 year ago

Posts: 250

Topic starter 17/06/2024 8:54 pm

@ecobaker absolutely correct - I'd only manually kick in the immersion when prices turn negative, so (a) I can store energy by heating DHW as high as possible (above my normal set point), and (b) allow me to run the DHW through the immersion AND the heating simultaneously (in winter), thus capitalising on any negative pricing slots.

Under normal circumstances (i.e, if I'm paying for it), the immersion stays off as it's far more efficient to use the ASHP.

This post was modified 1 year ago by Mars

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