Posted by: @bontwoody

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Maybe a hammock might be better ....... 😆 

I don't think that vertical hammocks work too well. 😎 

Posted by: @bontwoody

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t was a mates idea

How heavy is the cylinder once filled? 😀 

Did I mention that im a dwarf 🙂

BTW I contacted Graham on linkedin and mentioned the youtube error. He already knew 🙂  He also reckoned that PWM on the Samsung doesnt work, so I think I will keep the pump I have!

@william1066 Its 150 lt so something under 200kg I guess. Im going to double up the plywood shelf and ive overdone the concrete screws on the sides so i reckon im safe enough 🙂

Posted by: @bontwoody

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Did I mention that im a dwarf 🙂

BTW I contacted Graham on linkedin and mentioned the youtube error. He already knew 🙂  He also reckoned that PWM on the Samsung doesnt work, so I think I will keep the pump I have!

I've seen that commentary from graham before that the Samsung G6 PWM doesn't work. it 100% does , I guarantee it , at least on my G6 system, with a UPMM pump. Which are both brand new. I'm hypothesising here but I wonder if there was a problem with it in earlier builds of the G6 and/or with particular pumps.  If you were to get a PWM UPM now, with a new G6, it'll work.

I actually keep a folding step/stool in the airing cupboard for when I'm tuning and tweaking (some stuff up high to be fair). the family keep asking me for it back when they need it so maybe I do need to fit a seat 🙂

Godammnit! now you have gone and muddied the waters again 😀 I guess the only argument to change the pump, is if it it would save me more in electricity over its lifetime than it would to change it. If I write off the £100 and estimate 10 years life, it has to save £10 a year. Its currently running at 50W lets say for 10 hours a day. Assuming a 25% saving thats 456 kWh over its lifetime, say £225. However that might not be true as I wont pay for all that electricity but I might get paid for export. Do you have any notion of how much more efficient the PWM pump might be than a standard one Ian? Is there also a saving from a better COP of the Heat Pump?

@bontwoody pump definitely runs at lower power when PWM'd down. what the effect on COP is I am not personally qualified to comment but there is plenty of other data out there in this forum, buildhub, john cantor, heatgeek, youtube, all sorts... that says PWM is good for COP, so I've taken all that as read and gone with it in my build! but there are other people who use fixed speed I think as well and get good COP... some on this forum. I'm not the expert, I went with what I understood to be the consensus of the experts.

one thing you can't argue with is flow rate noise. My system is a little flow rate noisy in some rads at full chat. once modulated down, its silent. but yours is a smaller system so will have a lower flow rate target so YMMV!

the only point I really wanted to correct is that one doing the rounds that "Samsung  pump PWM control doesn't work".  It 100% does with the right setup. Whilst acknowledging that some setups may have issues getting it working, there's the one in the other thread for example.

As to whether you should do PWM, thats a different question I can't answer for you!

Posted by: @bontwoody

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Godammnit! now you have gone and muddied the waters again 😀 I guess the only argument to change the pump, is if it it would save me more in electricity over its lifetime than it would to change it. If I write off the £100 and estimate 10 years life, it has to save £10 a year. Its currently running at 50W lets say for 10 hours a day. Assuming a 25% saving thats 456 kWh over its lifetime, say £225. However that might not be true as I wont pay for all that electricity but I might get paid for export. Do you have any notion of how much more efficient the PWM pump might be than a standard one Ian? Is there also a saving from a better COP of the Heat Pump?

If my understanding is correct, the major saving to be made would be in improved efficiency, due to reduced cycling.

In milder weather conditions the heat loss is lower and hence the heat demand from the heat pump is reduced. Correctly adjusted WC should lower the required LWT, which in turn should cause the compressor speed to be reduced, thereby producing less heat energy. The compressor has a minimum operating speed, which once reached, the only other way to reduce the quantity of heat energy being supplied to the heat emitters, is to either stop the compressor for a period of time, or reduce the water flow rate.

PWM control of the water pump is therefore used to maintain the 5C DeltaT between LWT and RWT, and hence reduce the likelihood of compressor cycling. How well it actually works in practice may be dependent upon having correctly matched equipment, which has been correctly configured to produce the desired results.

@derek-m @iancalderbank Thanks both for the input. Im coming down on the side that if PWM is working then I should probably go for it and order a new pump. I may be able to recoup some the cost by selling the old one which makes the sums look much better.

@bontwoody yay! the PWM gang gets another recruit. you can always keep the non-PWM one as emergency spare.

@iancalderbank Thats plan B if noone wants to buy it 😀 New pump now ordered!

Bad news Im afraid, Midsummer Wholesale took my order and confiirmed it and then the day after cancelled it saying they are now only supplying the water pump with a heat pump! It didnt say that when I ordered it (other pumps did). Very poor customer service IMO, they should have honoured the deal that was made. I wont be using them again, but finding another supplier is proving difficult.