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12kW Samsung gen 6 short cycling

Craig1980 · 2022-11-23T23:30:08Z

Good evening. Welcome to my life staring at my ASHP and scratching my head. I've had a Samsung gen 6 12kw ASHP fitted with all new pipework and rads on an eco4 grant so you can guess that I was just handed the room stats for each of the two zones and told to adjust with the stat.The system was set at 55 and no WC. No legionella either (although I've turned this off and will run manually as and when). The house is a medium 5 bed, cavity bead insulation, loft insulation and double glazing. It's a 60s house but modernised and well insulated for its age. It is in West Wales so fairly mild climate. I like to run the house at 18 degrees max so I've set the WC pretty low at 20 and -3, 20 and 31. I'm getting a good COP at around 3.7 although that has dropped to 3.4 today. Using around 16kw including water heating for up to an hour. Temp today is 8-9 degrees and the pump runs for around 7-8 mins, turns off for 18 seconds then runs again for 7-8 mins. It starts at 100w and peaks at 800w. House is sitting at around 19 degrees. Water law is set up on Floor, should it not be set on Fcu and rad? What diffeference would that make? External thermostat #1 and #2 and remote controller room temp are all set on "room temp on/off or WL interlink on/off (water pump 3)". Is that correct? My question is how can I stop the short cycling and how can I improve efficiency? Sorry for all the questions but I've driven myself mad staring at that screen. 🙈🤣

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Craig1980

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Topic starter 28/11/2022 7:12 pm

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Derek M

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28/11/2022 7:31 pm

Posted by: @craig1980

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@derek-m I didn't set them back to 21 straight away and left them for a day. At night it was longer between but by the next day it was back to the same.

Had the indoor temperature changed? A further test would be to watch closely the operation of the wireless receivers for the thermostats when the system performs its short off - on cycle.

Also check that all the plug and socket connections on the circuit board are making good contact.

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Craig1980

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Topic starter 28/11/2022 7:47 pm

@derek-m no change in the indoor temperature. The lights on the receivers do not change when it cycles on and off.

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Derek M

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28/11/2022 7:59 pm

Posted by: @craig1980

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@derek-m no change in the indoor temperature. The lights on the receivers do not change when it cycles on and off.

Did you close the airing cupboard door overnight? The reason I ask is that sometimes equipment, and circuit boards, can suffer intermittent faults due to thermal expansion.

What water law settings are applied at the moment?

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Craig1980

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Topic starter 28/11/2022 8:23 pm

@derek-m the airing cupboard door is always shut. It doesn't get that warm in there.

Pics of the screen set up of water law.

Not sure if the set up with "floor" is correct. Whether it should be FCU instead?

Also running -2 on the home screen which I'm led to believe is a short cut to adjusting a water law setting. Assuming the 31?

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HughF

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28/11/2022 9:56 pm

Posted by: @derek-m

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@hughf

Yes, I've seen all the different diagrams in the manuals, but it doesn't tell one which is correct. Also I don't see the point in having two pumps to do the job that one pump should be able to do.

I’d go with the one from the Jule installation manual, as it’s a Jule cylinder/heatpump package. Now that we’ve seen some more photo’s you can clearly see that the hydraulics match what is shown I their manual exactly.

Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.

My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.

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HughF

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28/11/2022 9:59 pm

Posted by: @derek-m

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Hi Hugh,

Do you know if the Samsung controller will still use WC when operating with the indoor temperature located within the controller?

I have a lot of time for Glyn Hudson over on YouTube who has just DIYd his 5kW Samsung install and has documented it with a decent video. From the comments I’ve been having with his, he says that the Samsung will still use WC when the wired controller is used as for measuring room temperature. I’ve asked him if the controller will also support load compensation and reduce the flow temperature when the room is approaching the target temp. Inversely, increasing the flow temp to recover quickly from a nighttime or away/holiday mode setback temperature.

He uses a single pump (with PWM control) on his setup but his primary pipe work is short.

Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.

My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.

👍

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HughF

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28/11/2022 10:35 pm

Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.

My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.

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Craig1980

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Topic starter 28/11/2022 10:47 pm

@hughf thanks for looking in to this.

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Derek M

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28/11/2022 11:02 pm

@craig1980

Let me have a read through the manual and decipher what some of the descriptions mean. I'll get back to you tomorrow.

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Craig1980

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Topic starter 28/11/2022 11:13 pm

Great, thanks. This is all very helpful

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HughF

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28/11/2022 11:53 pm

Glyn has his 5kW Samsung wired/plumbed up with full monitoring, the data can be viewed at:

https://emoncms.org/samsung5kw

Single grundfos PWM pump, a heatpump cylinder with a 1m2 coil (the same cylinder I’ve got - they were cheap on eBay back in the summer), and radiators throughout.

Off grid on the isle of purbeck
2.4kW solar, 15kWh Seplos Mason, Outback power systems 3kW inverter/charger, solid fuel heating with air/air for shoulder months, 10 acres of heathland/woods.

My wife’s house: 1946 3 bed end of terrace in Somerset, ASHP with rads + UFH, triple glazed, retrofit IWI in troublesome rooms, small rear extension.

👍

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