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12kW Samsung gen 6 short cycling

 
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 Craig1980
(@craig1980)
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Joined: 3 years ago
Posts: 146
Topic starter 24/11/2022 12:30 am  

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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 HughF
(@hughf)
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Joined: 3 years ago
Posts: 489
24/11/2022 9:03 am  

12kW eh….. seems large. What did the heat loss calcs show your heating load to be?

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
(@craig1980)
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Posts: 146
Topic starter 24/11/2022 9:17 am  

Hi. Unfortunately it was an eco4 grant installation so I doubt they even bothered with heat loss calcs. Likely just a guess and slap it in. 🤣

12kw does seem about right when speaking to others and what size they have. 

The house is 164sq/m detached in an exposed spot near the coast in Pembrokeshire. 


   
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 HughF
(@hughf)
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Posts: 489
24/11/2022 10:16 am  

Some pictures of the plumbing in/around the area of the UVC if you could sir... We'll see if we can figure out how this is plumbed up and address the short cycling.

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
(@craig1980)
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Posts: 146
Topic starter 24/11/2022 10:20 am  

@hughf of course. But what is a UVC? 🙈


   
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 Craig1980
(@craig1980)
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Joined: 3 years ago
Posts: 146
Topic starter 24/11/2022 10:26 am  

Might've just worked it out, unvented cylinder?

received 830198528323080

 


   
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 Craig1980
(@craig1980)
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Joined: 3 years ago
Posts: 146
Topic starter 24/11/2022 10:27 am  
16692819929054826035346384975561

   
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 Craig1980
(@craig1980)
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Joined: 3 years ago
Posts: 146
Topic starter 24/11/2022 10:28 am  
16692820845447559183326994323301

   
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 HughF
(@hughf)
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Joined: 3 years ago
Posts: 489
24/11/2022 10:38 am  

@craig1980 Yes, UVC is plumber slang for Unvented Cylinder.

OK, so we've got a standard Samsung setup with two external pumps (Why they can't put the pump in the monobloc is beyond me). The pump that is directly below the port marked 'Heat Pump return' - does that have one or two cables connected to it?

 

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
(@craig1980)
Reputable Member Member
Joined: 3 years ago
Posts: 146
Topic starter 24/11/2022 10:56 am  

@hughf just one cable to each one.


   
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 Craig1980
(@craig1980)
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Joined: 3 years ago
Posts: 146
Topic starter 24/11/2022 10:59 am  

For information this is my flow temps now. It currently runs for around 7-8 mins then off for 3-4 mins. When running it's using 0.8kw. 

It's 10 degrees windy and raining here today.

16692839768978290294203072131329

 


   
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 Transparent
(@transparent)
Illustrious Member Moderator
Joined: 4 years ago
Posts: 2437
24/11/2022 11:04 am  

Posted by: @craig1980
↑

it was an eco4 grant installation so I doubt they even bothered with heat loss calcs.

Then they've left themselves in a tricky position as regards Part-L Section-7 of the Building Regulations:

Part7 annot

and Sections 3 & 4 of the same Part-L

PartL 3+4

You could contact your Local Planning Authority's Building Control Dept and ask if they have been properly notified about the installation at your site. They have the power of enforcement if the terms of the Building Act have not been complied with.

You should have a schematic of your installation and notes on how to operate/maintain it. It isn't sufficient to give you a pile of manufacturers' manuals for the individual component parts of the system! 🤔 

Within the documentation which you do have, there should also be a response from National Grid Electricity Distribution (formerly Western Power). Your installer will have filed an application under the regulations for Low Carbon Technology (LCT). You would need that response if you ever wanted to sell the property because it's the only evidence you have of compliance.

 

Posted by: @craig1980
↑

My question is how can I stop the short cycling and how can I improve efficiency? 

Firstly I'd be pretty pleased to have a COP between 3.4 - 3.7 on a new ASHP installation that's still suffering from cycling 😊 

But there are others here with more knowledge than I about how to attempt a remedy.

 

Posted by: @craig1980
↑

The house is 164sq/m detached in an exposed spot near the coast in Pembrokeshire.

That sounds like a great location for a wind-turbine and storage battery to run the ASHP at low cost over winter.

Have your visits to this forum yet enabled you to find the live topic about Wind Turbines and Planning?

Save energy... recycle electrons!


   
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