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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 01/12/2022 12:50 pm

Here you go

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Craig1980

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Topic starter 01/12/2022 12:52 pm

Measurements in brackets are on 35 flow temp setting.

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Craig1980

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Topic starter 01/12/2022 1:10 pm

Room temp is slowly climbing. Up to 19 now.

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Derek M

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01/12/2022 1:17 pm

@craig1980

Thanks Craig, now lower the LWT setting to 30C and see what happens to how the system operates.

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Derek M

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01/12/2022 1:28 pm

Posted by: @craig1980

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Room temp is slowly climbing. Up to 19 now.

That is to be expected during the testing. What changes have you made to the Field Setting Values?

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Craig1980

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Topic starter 01/12/2022 3:43 pm

@derek-m none. I've just followed what it said in the video link that I sent then set to 35 now set to 30 and timing shut downs as it has turned on and off.

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Craig1980

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Topic starter 01/12/2022 3:47 pm

Right, finished timing. Now back to 8 mins on 20 seconds off again.

Flow temp 28.1 set to 30

Indoor 22.1

Outdoor 6.5

Room temp 19

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Derek M

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01/12/2022 4:48 pm

Posted by: @craig1980

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Right, finished timing. Now back to 8 mins on 20 seconds off again.

Flow temp 28.1 set to 30

Indoor 22.1

Outdoor 6.5

Room temp 19

Hi Craig,

I'm afraid that I have run out of suggestions.

There appears to be something fundamentally wrong with your heat pump, and/or how the system has been installed. The only thing that I can see that appears to be incorrect is the Teva_out temperature reading of -50C, which could possibly be due to a faulty or disconnected temperature sensor.

I would suggest that you e-mail Samsung Technical Help and ask them why your system may be operating as it is doing.

In the meantime set your system back onto WC mode and adjust for the required indoor temperature.

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Craig1980

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Topic starter 01/12/2022 4:59 pm

Okay, many thanks for all of your help. I'll update if I find anything from Samsung. Thanks again. Much appreciated.

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Craig1980

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Topic starter 01/12/2022 5:23 pm

Interestingly, when I put the settings back to WC I get error E121. Upon looking this up in the manual it says

"Short-or open- circuit error of the room temperature sensor of the zone 1 indoor unit (detected only when the room thermostat is used) Error source - Hydro unit.

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Mike H

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01/12/2022 8:32 pm

Posted by: @hughf

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Posted by: @mike-h

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Am I right in thinking that Craig's system (from Joule) does not have a buffer tank? I'm still trying to get my head round the mandatory buffer tank for Samsung ASHP question.

It doesn't have a buffer, no...

Which set of instructions say that the samsung needs a buffer?

@hughf Please see the topic about Samsung install and buffer tank

https://renewableheatinghub.co.uk/forums/postid/11342

Freedom Heat Pumps claims a buffer tank is required to be within the Samsung warranty, even though the manual implies otherwise and Joule make a pre-plumbed cylinder without a buffer tank.

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HughF

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01/12/2022 8:55 pm

@mike-h Ah yes, good old freedom. I’d trust the instructions from midsummer wholesale personally. I know that GH was always getting 911 errors (low flow) on his early installs, so they probably mandated a buffer to deal with that issue, allowing the primary pump to run at full speed to charge the buffer.

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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