Posted by: @david999

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@derek-m 16 radiators samsung wanted a 46lpm flow rate on 35mm pipe and seem to be supporting the installer by diluting this down to 36lpm on 28mm pipe. It’s a 16kw heat pump and the first stats are what’s detailed for both that pump and the 13kw.  Flow is everything on a heat pump, to fast and it’s noisy and you get erosion corrosion and too slow it runs inefficiently.

I would suggest that you check the water volume of each radiator on the manufacturer's website or Screwfix if you don't know the manufacturer. Then estimate the water volume in the pipework, along with the specified volume of the buffer tank and heat pump. You should therefore be able to assess the approximate water volume within your system. If the concentration of anti-freeze is to be say 20%, then that would indicate a total system volume in the region of 500 Litres. This seems on the high side.

The efficiency of a heat pump is primarily determined by the Leaving Water Temperature (LWT), which needs to high enough to cause the required quantity of thermal energy to be emitted by the heat emitters. If the flow rate is reduced by say 20%, then the DT across the heat emitters may increase from 5C to 6C, which in turn may slightly reduce the heat pump efficiency if the LWT needs to increase to compensate.

@derek-m I completed the assessment in collaboration with Fernox tech and came to around 280 litres. Requiring a mix to provide protection to -20/25 . Cant remember the mix at the min.

checked the filters when they left just for curiosity, the magnetic had a bit of sludge on it again and the outside filter bowl is missing the filter. The apprentice butchered the circlip last time and obviously he tossed it all. 

I will let it cool down and see how it runs from cold.  It says inverter pump 100%, could you tell me what that is and what it does 

Posted by: @david999

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@derek-m I completed the assessment in collaboration with Fernox tech and came to around 280 litres. Requiring a mix to provide protection to -20/25 . Cant remember the mix at the min.

checked the filters when they left just for curiosity, the magnetic had a bit of sludge on it again and the outside filter bowl is missing the filter. The apprentice butchered the circlip last time and obviously he tossed it all. 

I will let it cool down and see how it runs from cold.  It says inverter pump 100%, could you tell me what that is and what it does 

The Inverter is used to control the speed of the compressor.

Can you provide details of where you are seeing this message, also the model number of the heat pump and controller so that I can confirm we are both looking at the same manual.

@david999

According to the manual for the controller under Field Setting Value, the 'Inverter Pump Installation' is a field option, which means it may not be installed.

I'm not certain exactly what is meant by Inverter Pump, which the manual does not appear to explain. You could try asking Samsung.

I would suggest that you check the value of FSV #4051 and FSV #4052 and report back.

@transparent it has a room stat which I’m not sure I should be using, but I need some control over the rooms so Trv on the rads allows that. Generally we manage nicely on 19-20c  throughout other than bedrooms and not sure you could lower flow temp that low. Presuming it switches to 50c for hot water with the 3 port. Still learning it yet. Our house is well insulated so it doesn’t run long but I guess on a very cold day it might cycle a bit. 

if I turned the room stat to 30c opened all the trvs on the radiators to max then set my flow temp to 20c are you saying that’s cheaper than my system controlling all the rooms individually and the room stat cycling the heat pump every so often.  I don’t know what’s best yet I’m awaiting one of those smart gadgets from octopus so I can view my usages. 

@derek-m 4051 reads use max 100%

4052 reads 5.0c

Posted by: @david999

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@transparent it has a room stat which I’m not sure I should be using, but I need some control over the rooms so Trv on the rads allows that. Generally we manage nicely on 19-20c  throughout other than bedrooms and not sure you could lower flow temp that low. Presuming it switches to 50c for hot water with the 3 port. Still learning it yet. Our house is well insulated so it doesn’t run long but I guess on a very cold day it might cycle a bit. 

if I turned the room stat to 30c opened all the trvs on the radiators to max then set my flow temp to 20c are you saying that’s cheaper than my system controlling all the rooms individually and the room stat cycling the heat pump every so often.  I don’t know what’s best yet I’m awaiting one of those smart gadgets from octopus so I can view my usages. 

Turning the room stat (and all or most TRVs) up to (say) 2C above the desired temperature, and adjusting the flow temperature (via the WC curve) to the lowest possible that results in the desired room temp (balancing the rads if necessary), is the most efficient way to run a heat pump.  That's just the thermodynamics in operation.  Lowest flow temp = max efficiency.

Of course there are some subtleties at the edges, but fundamentally on/off control of heat pumps to achieve a desired room temperature is bad for efficiency.  Low and slow!

Posted by: @david999

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@derek-m 4051 reads use max 100%

4052 reads 5.0c

The parameter FSV #4051 should contain the value 0, 1 or 2, so you are probably looking at the displayed result rather than the actual set value. To change any of the set values you will probably need to be in 'Installer Mode' or Samsungs equivalent.

The default value for FSV #4051 is 1, which apparently sets the system to operate with 'Inverter pump use + Output 100%. This could have a number of meanings, so here is my educated guess.

'Inverter pump use' - means that the speed of the water pump is varied by the controller.

+ Output 100% - could mean that the water pump can go up to 100% or that the heat pump itself can go to 100% output. If FSV #4051 is set to a value of 2 the Output is limited at 70%.

The default value for FSV #4052 is 5, which sets the system to operate with a DT of 5C between LWT and RWT. The range of adjustment being from 2C to 8C.

If the speed of the water pump is actually controlled by the controller then the system should operate in the following manner.

When the heat pump is first started the speed of the compressor will be increased to raise the LWT, the speed of the water pup will also increase to push the warm water around the system.

As the Return Water Temperature (RWT) starts to increase as the water flows through the system and back to the heat pump, the water pump should reduce the flow to try to maintain the DT at 5C (the setting of FSV #4052).

As the Indoor Air Temperature (IAT) starts to rise the compressor should start to reduce speed, thereby producing less thermal energy output from the heat pump. Dependent upon the setting of the Weather Compensation (WC) curve the IAT will reach a balance point, or the compressor will be stopped by the heat pump controller or your external thermostat.

For most efficient operation all TRV's (except possibly bedrooms) should be fully open, and the WC curve should be adjusted to match the actual heat loss at different Outside Air Temperatures (OAT).

@david999 You say ‘I’m awaiting one of those smart gadgets from octopus so I can view my usages.’ If that is the Octopus Mini, then don’t hold your breath - I’ve been waiting over a year now, they have confirmed I’m on the list but…. Regards, Toodles.

@toodles yup that’s what it is and I have been waiting a year as well, messaged them again but no sign of one. I had the Scottish power one but it was problematic. The Samsung heat pump gives figures but they are nowhere near the facts.

Posted by: @david999

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@toodles yup that’s what it is and I have been waiting a year as well, messaged them again but no sign of one. I had the Scottish power one but it was problematic. The Samsung heat pump gives figures but they are nowhere near the facts.

er dont you just need a smart meter which I think your energy supplier can arrange to have fitted within 14-28 days.

That's all I have, and I can both visualise and download my half hourly meter readings on the Octopus website (other suppliers also make downloads possible I believe).

Of course that wont separate your heat pump consumption from other electricity consumption, but I dont think that the octopus mini does that either.

@david999 The OE Mini is a project started up by an ‘Intern’ I believe and they are still being produced on a small scale production system using recycled materials - I am looking forward to receiving mine too! Toodles.