SunAmp : Snog, Marry, Avoid?

[Onoff]

6 hours ago, Nickfromwales said:

Tin Hat suitably super-glued on and awaiting the flack...…..

 

So is it the case that an old model, smaller sized Sunamp PV worked "better" than a new, larger sized UniQ because of limitations imposed by SA on the new range? If so SA should have said a long time ago they were redesigning for a mass market and that to achieve similar results to the old PV then go up a size.

 

The customer now has to bear the cost of the uplift due to the value engineering that's gone on?

 

Taking the long term view then tbh, IF the tech works I'd live with that and another £600 or whatever for a couple of units. 

 

I'd always be thinking though that I've a dumbed down model that could have been better.

[le-cerveau]

18 hours ago, Dreadnaught said:

 

58 I assume. But, I wonder, is there a role for a PCM 34 cell too, @le-cerveau-style? Presumably not. Which makes me wonder why @le-cerveau went for both types of cell, especially when PCM 34 has had some issues, although I think those issues are now resolved.

My PCM34 cells are effectively an ASHP buffer, they are charged by my ASHP up to 45^oC, the ASHP shuts down at about 42 when the SA unit stops calling for heat.  They are used as the the UFH buffer and also DHW pre-heat.  The PCM58 cells then provide the DHW.

[Jeremy Harris]

3 hours ago, Onoff said:

 

So is it the case that an old model, smaller sized Sunamp PV worked "better" than a new, larger sized UniQ because of limitations imposed by SA on the new range? If so SA should have said a long time ago they were redesigning for a mass market and that to achieve similar results to the old PV then go up a size.

 

The customer now has to bear the cost of the uplift due to the value engineering that's gone on?

 

Taking the long term view then tbh, IF the tech works I'd live with that and another £600 or whatever for a couple of units. 

 

I'd always be thinking though that I've a dumbed down model that could have been better.

 

 

I've owned and lived with both versions of the Sunamp, probably one of very few that have, plus I've now got 3 1/2 years experience with these things, a fair bit longer than anyone here, and longer than any Sunamp installer (there were none at all when I fitted our Sunamp PV).

 

I can say categorically that, as far as the electrically heated models are concerned, the Sunamp PV was significantly more reliable, worked pretty much exactly like an immersion in a hot water tank and was able to utilise all of the heat storage capacity available, i.e. the 5 kWh model could usefully store and deliver 5 kWh.

 

On the other hand, the electrically heated Sunamp UniQ models are far less capable.  They can only usefully store around half their rated capacity, even though they are practically double the weight and significantly larger.  What's worse is that in practice, they can deliver LESS than half their rated capacity when used with an excess PV generation diverter.  We never ran out of hot water with the Sunamp PV, with it's 5 kWh capacity, but have run out twice with the much bigger 9 kWh capacity Sunamp UniQ.  What's more, we would have run out of hot water many more times if I hadn't discovered that this could be prevented by resetting the unit manually every day.

 

I've stressed the electrically heated models above because both models we've had have only been electrically heated.  If heated with hot water, then I would guess that the major flaw in the controller that we have experienced may well either not be an issue, or be an issue that can be easily worked around.  As long as a hot water heated model is provided with hot water at a few degrees above the PCM phase transition temperature of either 34°C or 58°C then it will charge, if there is any charge capacity available.

 

I'm afraid I do not agree that the solution to the flaw in the controller is to just spend a lot more money on a unit that has twice the storage capacity required.  It may get around the severe design flaw in the controller, but frankly a 9 kWh unit should be able to always store and deliver 9 kWh, not be artificially de-rated by an installer to 4.5 kWh, as bodge to cover up inadequacies in the product.  Apart from anything else, the specifications are clear, and if a 9 kWh model is not able to reliably deliver 9 kWh every day, then it's not compliant with the manufacturers specification, so should be marketed  as a 4.5 kWh model.

[Dreadnaught]

@JSHarris to achieve your target 9 kWh capacity in this new de-rated world, you'd presumably have needed to buy an 18 kWh model (if such a thing exists). How about getting that up your stairs? How much would that weigh?

[Onoff]

12 minutes ago, JSHarris said:

not be artificially de-rated by an installer to 4.5 kWh, as bodge to cover up inadequacies in the product

 

That's a bit unfair on the installer,  poor choice of words maybe? More a case the installer shouldn't have to over specify. The installer doesn't decide / stamp the rating.

[Onoff]

3 minutes ago, Dreadnaught said:

@JSHarris to achieve your target 9 kWh capacity in this new de-rated world, you'd presumably have needed to buy an 18 kWh model (if such a thing exists). How about getting that up your stairs? How much would that weigh?

 

Not an issue, SA will pay to beef your structure up! ?

[Nickfromwales]

1 hour ago, paulmb said:

In the discussion of using ASHP's with SA products, can someone clarify where the 'rHW' and 'rHeat' configurations fit?  I'm referring to the SA products:

 

• UniQ rHW Heat battery for domestic hot water only, which is heated by an external heat pump using the heat pump refrigerant circuit i.e. the refrigerant flows through the heat exchanger in the UniQ rHW store. (OEM only) 

• UniQ rHeat Heat battery for space heating only, which is heated by an external heat pump using the heat pump refrigerant circuit i.e. the refrigerant flows through the heat exchanger in the UniQ rHeat store. (OEM only) 

I'm not familiar in detail with ASHP's, but was told yesterday that there are some that require a 'refrigeration engineer' to install and service, and some that don't - so do the above SA models require a refrigeration engineer and hence why they're only available to OEM channels?  If that's the case, then is all other discussion of ASHP's here referring to ones that produce hot water as output?

Yes, all chat to date has been about air to water HP's. The one that's described above, the r-prefix, takes F-gas directly into the SA heat exchanger to melt the PCM directly with the energy produced by a dedicated HP. The idea being that the whole setup doesn't suffer the losses of going air-water-HEx eg the losses of the conversion in the HP and also the losses downstream of the hydraulic circuit in between the two units. In honesty I have not asked recently if these units are to market currently. I shall enquire though as I did like the idea when I was made aware of the principle some time ago.

The PCM58 needs a flow temp in excess of 58oC to melt the PCM, so a 'regular' ASHP is no good, as it's probably going to max out at 58oC at the HP ( at which point the CoP would be in the gutter ), and then the losses in the hydraulic circuit will see less than that actually arrive at the SA. The SA's I've seen working with HP's so far have all been high-temp heat pumps which give 650C to the SA. These HP's have also been doing space heating via upsized radiators with some iirc storing off peak produced energy for space heating between off peak events.

 

1 hour ago, paulmb said:

 

I'm not sure that the above is completely the case - as just last week I innocently entered an enquiry on the SA web site which was responded to with a call from a SA business development manager, followed by an email containing version 2.3 of the Uniq Heat Batteries reference manual, and a couple of followup email exchanges.  It's gone a little quiet since I referenced the dialogue's on this forum to them...

Like I said, tin hat  

[Pete]

4 minutes ago, JSHarris said:

 

 

I've owned and lived with both versions of the Sunamp, probably one of very few that have, plus I've now got 3 1/2 years experience with these things, a fair bit longer than anyone here, and longer than any Sunamp installer (there were none at all when I fitted our Sunamp PV.

 

I can say categorically that, as far as the electrically heated models are concerned, the Sunamp PV was significantly more reliable, worked pretty much exactly like an immersion in a hot water tank and was able to utilise all of the heat storage capacity available, i.e. the 5 kWh model could usefully store and deliver 5 kWh.

 

On the other hand, the electrically heated Sunamp UniQ models are far less capable.  They can only usefully store around half their rated capacity, even though they are practically double the weight and significantly larger.  What's worse is that in practice, they can deliver LESS than half their rated capacity when used with an excess PV generation diverter.  We never ran out of hot water with the Sunamp PV, with it's 5 kWh capacity, but have run out twice with the much bigger 9 kWh capacity Sunamp UniQ.  What's more, we would have run out of hot water many more times if I hadn't discovered that this could be prevented by resetting the unit manually every day.

 

I've stressed the electrically heated models above because both models we've had have only been electrically heated.  If heated with hot water, then I would guess that the major flaw in the controller that we have experienced may well either not be an issue, or be an issue that can be easily worked around.  As long as a hot water heated model is provided with hot water at a few degrees above the PCM phase transition temperature of either 34°C or 58°C then it will charge, if there is any charge capacity available.

 

I'm afraid I do not agree that the solution to the flaw in the controller is to just spend a lot more money on a unit that has twice the storage capacity required.  It may get around the severe design flaw in the controller, but frankly a 9 kWh unit should be able to always store and deliver 9 kWh, not be artificially de-rated by an installer to 4.5 kWh.  Apart from anything else, the specifications are clear, and if a 9 kWh model is not able to reliably deliver 9 kWh every day, then it's not compliant with the manufacturers specification, so should be marketed  as a 4.5 kWh model.

So, I have read the thread again and are we any nearer to making a decision? We have @JSHarris giving the actual details/problems he has experienced plus @Barney12. We have @Nickfromwales explaining from a designer's/ installer's point of view but does not really address the issues that Jeremy has mentioned, or if he did it went straight over my head. I really appreciate the effort people are putting into this debate as we are interested in the SA but not until we can be sure we have chosen correctly. 

[Jeremy Harris]

3 minutes ago, Dreadnaught said:

@JSHarris to achieve your target 9 kWh capacity in this new de-rated world, you'd presumably have needed to buy an 18 kWh model (if such a thing exists). How about getting that up your stairs? How much would that weigh?

 

The 5 kWh Sunamp PV weighed about 70kg.

 

The 9 kWh eHW unit weighs about 160kg

 

As there isn't an 18 kWh version, then it would have to be two 9 kWh models, so about 320 kg

 

3 minutes ago, Onoff said:

 

That's a bit unfair on the installer,  poor choice of words maybe? More a case the installer shouldn't have to over specify. The installer doesn't decide / stamp the rating.

 

Yes, you're probably right, an installer should not feel the need to double up on the specification because he or she knows that the true usable capacity is half that in the specification.

 

[newhome]

8 hours ago, Nickfromwales said:

where most here probably do not know that SA have now pulled away from the public as aforementioned, in recent months, to ensure this kind of error cannot happen anymore

 

I’m not entirely convinced by this. Most people buying from SunAmp when they were still selling to the public wouldn’t rock up and say I need a model A, they would provide Sunamp with their requirements and be told you need a Model B. I wonder if Sunamp themselves didn’t fully understand the implications of the 50% setting when someone was using it with PV and thus specified the wrong model. As an example one of my colleagues bought a full system from Sunamp (ASHP, Sunamp for DHW, MCS install) last July. His remit was to use his excess PV for his DHW. Sunamp specified a UniQ eHW 6. For reasons best known to Sunamp this system still hasn’t been fitted some 7, nearly 8 months after paying them 10k but having read your ‘over specifying to compensate’ comment I wonder if that model is really going to be suitable for his excess PV. Yes he will be able to top up using electric but the primary purpose was to use excess PV. But it was Sunamp who specified it so it must be adequate, right? ?

 

 

[Jeremy Harris]

FWIW, when I contacted Sunamp towards the end of last summer, looking to possibly change our Sunamp PV (rated at 5 kWh, and which reliably delivered 5 kWh) Sunamp's initial suggestion was for me to replace it with a Sunamp UniQ 6 eHW (rated at 6 kWh).

 

At that time it was clear that they believed that the 6 kWh model would equal or exceed the capacity of the 5 kWh Sunamp PV, and given their very good track record with the Sunamp PV I had no reason not to believe this.  There was no mention of needing to de-rate the new unit by 50% (or over-specify by 100%).  I opted to increase the capacity to 9 kWh for the reasons given earlier, I wanted to be able to store a reserve from days when we had a lot of excess PV generation, so it could be used if the following day had very little (yesterday and today here would be a good example - yesterday we generated around 27 kWh, today I doubt if we will generate 2 kWh).

 

At no time was there any mention of the need, or desirability, to double the capacity of the unit in order to be able to reliably deliver the required capacity.

[Nickfromwales]

6 minutes ago, Onoff said:

 

That's a bit unfair on the installer,  poor choice of words maybe? More a case the installer shouldn't have to over specify. The installer doesn't decide / stamp the rating.

Pretty much.

3 minutes ago, JSHarris said:

Yes, you're probably right, an installer should not feel the need to double up on the specification because he or she knows that the true usable capacity is half that in the specification.

That statement I made was a little 'broad', as I have made no such consideration in the instance of the property with both a 3 and a 6 ( as they were already on site when I was asked to go and fit them ) and the 3 is currently. However, I will add that those units were being fed by grid electricity on demand and when the client gets around to fitting his PV diversion controller which I think is now done tbh I shall be in contact to get some feedback ( if they don't contact me first that is ).

In fairness, if @JSHarris had a teenage daughter and 3 showers were drawn every morning / nigh time then the likelihood is that this thread wouldn't exist. It's only because the sizing and the usage of DHW have created the perfect storm that this is apparent, so is actually focussing on the weakness not the strength of the SA controller. Take for eg the install with the size 9, with two adults and one child, who I have not heard one peep from since leaving. They clearly live the other side of the 50% difficulty and Jeremy lives t'other.

 

I wonder if there is a way to convey the fact that there is export occurring to trigger the timeclock / low current interrupter so that it bumps the SA into 'hunt' and it would then scoff up any excess. 

[ProDave]

So reading the above posts since @Nickfromwales raised his tin hat above the parapet.  The situation can be summarised as follows:

 

For an electrically heated unit, SA recognise the 50% "problem" and have "solved" it by telling the installer to specify a larger unit to stand a chance of delivering the amount of hot water the customer expects.  While from the customers point of view, they will get a unit that works, it will be at THEIR expense of paying for a bigger unit that they really ought to need, and the installer may or may not have been too shy to actually tell them they are paying extra to overcome a known problem that SA don't seem willing to properly deal with.

 

So while Mt & Mrs Smith may be happy, I am afraid that is once humongous "sweep it under the carpet" exercise.

[Jeremy Harris]

3 minutes ago, Nickfromwales said:

I wonder if there is a way to convey the fact that there is export occurring to trigger the timeclock / low current interrupter so that it bumps the SA into 'hunt' and it would then scoff up any excess. 

 

There must be an easy fix, as just powering the controller off and then on again cures the problem completely.  Every single time I do this the controller resets and starts accepting charge, with no exceptions.  Doing this reset makes the Sunamp UniQ eHW work 100% reliably.

 

The problem looks to me to be related to there being no real time clock in the controller, so timing is a bit arbitrary, and I doubt if elapsed time is used at all in the logical test that determines when to allow the unit to accept charge.  I can easily add a timer to reset the unit, and am absolutely certain that would fix the problem permanently, but I'm reluctant to do this until we've heard from Sunamp (they are aware of the problem, at a pretty high level within the company).

[ToughButterCup]

Apologies to @PeterStarck : I deleted his last post by accident. Sorry Pete...

More evidence of my descent into a second childhood.

Ian

[Gone West]

39 minutes ago, JSHarris said:

The 9 kWh eHW unit weighs about 160kg

 

As there isn't an 18 kWh version, then it would have to be two 9 kWh models, so about 320 kg

Okay I try again . What is the advantage of two 9kWh models compared to a UVC storing water at 45C.

[Gone West]

Almost word for word.

[Gone West]

@recoveringacademic It'll keep you busy tidying up that lot.

[Gone West]

@recoveringacademic Revenge is sweet .

 

You'll know maybe that I can edit your posts Peter? 

Edited February 28, 2019 by recoveringacademic
Cussedness on the moderators part

[Jeremy Harris]

3 minutes ago, PeterStarck said:

Okay I try again . What is the advantage of two 9kWh models compared to a UVC storing water at 45C.

 

I would have said the reduced heat loss, but having just looked at the specification again I'm not at all sure that's correct.  If it's sensible, as @Nickfromwales suggests, to over-specify the capacity to be sure of being able to reliably deliver a requirement that's around half the specified capacity, then the reduced heat loss advantage almost disappears, and the cost is so much greater than a hot water cylinder that it doesn't make economic sense.  The only slight advantage would then seem to be that the overall height of a Sunamp installation would be around half that of a hot water cylinder, but the footprint would be much the same, maybe slightly greater.

[Nickfromwales]

7 minutes ago, ProDave said:

So reading the above posts since @Nickfromwales raised his tin hat above the parapet.  The situation can be summarised as follows:

 

For an electrically heated unit, SA recognise the 50% "problem" and have "solved" it by telling the installer to specify a larger unit to stand a chance of delivering the amount of hot water the customer expects.  While from the customers point of view, they will get a unit that works, it will be at THEIR expense of paying for a bigger unit that they really ought to need, and the installer may or may not have been too shy to actually tell them they are paying extra to overcome a known problem that SA don't seem willing to properly deal with.

 

So while Mt & Mrs Smith may be happy, I am afraid that is once humongous "sweep it under the carpet" exercise.

Not exactly what I said.

So, to further clarify;

As an installer and a person who has an active interest in SA I have put myself forward as an installer. As an installer I have deemed BY MYSELF that there is an effective workaround to the 'issue' that only @JSHarris has currently highlighted ( please inform me if there are others who have stated this EXACT issue as I am not currently aware of any other like instances ).

I have not been told to do this by SA and they do not see an issue at this time. 

21 minutes ago, ProDave said:

SA recognise the 50% "problem" and have "solved" it by telling the installer to specify a larger unit to stand a chance of delivering the amount of hot water the customer expects

I have had an agreement from SA that it is always best to be cautious when sizing for capacity, so the above is MY take on how the units should be sized and implemented. SA have not 'recognised' anything of the sort and I very much doubt they'll change the entire fleet over what is from their perspective an isolated case. What the facts are and how this has been identified as problematic extend to my comment about the perfect storm. That is apparent in many technologies and is simply an instance here as highlights a weakness created by this 'feature'.

For you tin hat I say what about all the others in, working, and without complaint?

I oversize everything in all things I do, because incrementally it's a safe bet. If someone is to give £1600 for a 6 which may just do it, then I would not entertain fitting it unless they went with a 9. same goes for the 9, if its borderline then I'll recommend a 12. I do the same with radiators and gas boilers, as you can turn a big radiator down but you cant turn a small radiator up.

[Nickfromwales]

29 minutes ago, ProDave said:

So while Mt & Mrs Smith may be happy, I am afraid that is once humongous "sweep it under the carpet" exercise.

Nonsense.

[Jeremy Harris]

Interestingly, for anyone looking at using an electrically heated Sunamp, charged either by off-peak electricity on a time switch, or excess PV generation, then there is a very good case for not over-sizing at all.  If I had opted for a UniQ 6 as a replacement for our Sunamp PV we would definitely have not had any problems with the controller 50% threshold, as every day we would have used at least 65% of the full capacity.  It was my decision (and it was my decision, Sunamp suggested I buy the UniQ 6 as a replacement for the 5 kWh Sunamp PV) to choose to over-specify, by opting for the 9 kWh model, when I knew that our requirement was usually around 4 to 4.5 kWh per day.

[ProDave]

1 minute ago, JSHarris said:

Interestingly, for anyone looking at using an electrically heated Sunamp, charged either by off-peak electricity on a time switch, or excess PV generation, then there is a very good case for not over-sizing at all.  If I had opted for a UniQ 6 as a replacement for our Sunamp PV we would definitely have not had any problems with the controller 50% threshold, as every day we would have used at least 65% of the full capacity.  It was my decision (and it was my decision, Sunamp suggested I buy the UniQ 6 as a replacement for the 5 kWh Sunamp PV) to choose to over-specify the Sunamp UniQ model, by opting for the 9 kWh model, when I knew that our requirement was usually around 4 to 4.5 kWh per day.

Interesting. The plot thickens.

[Nickfromwales]

4 minutes ago, JSHarris said:

 

I would have said the reduced heat loss, but having just looked at the specification again I'm not at all sure that's correct.  If it's sensible, as @Nickfromwales suggests, to over-specify the capacity to be sure of being able to reliably deliver a requirement that's around half the specified capacity, then the reduced heat loss advantage almost disappears, and the cost is so much greater than a hot water cylinder that it doesn't make economic sense.  The only slight advantage would then seem to be that the overall height of a Sunamp installation would be around half that of a hot water cylinder, but the footprint would be much the same, maybe slightly greater.

Yes, in essence, but I would not go to 2x 9's I would go to 1x 12. A 9 is equivalent to a 212L UVC, and that is fit for most domestic homes with the Smiths and their 2.4 children, so a 12 would be ample.

I would only go to 2x x sized units if the DHW demand was high and then the SA would out-perform the equivalent UVC hands down, plus to answer @PeterStarck's question fully, there would be no pressure reducing valve, no cold mains pressure relief valve, no temp and pressure relief valve, no D1 and D2 overflow / discharge pipework, no G3 installation criteria and zero ongoing G3 annual inspection ( for the life of the U|VC ) which would equate to a saving over 20 years of around £2k minimum. A proper G3 annual inspection should comprise of the draining down of all of the hot water from the tank, then a witness of the tank reheating and the control valves / thermostats all shutting off accordingly, then a manual test of the PRV's ( which makes the bloody thigs start leaking / passing water so any installer will refuse to touch them without that caveat in place ), and then a full visual inspection of the D1 and D2 discharging to waste...…...followed by isolation of the cold water supply, draining off of the head of cold mains pressure, then the checking of the pre-charge pressure in the 'gassed' side of the expansion vessel to ensure the EV is in good order / the bladder hasn't ruptured. What a damn ball-ache!!!!!!! Anyone who does any less than the above has NOT carried out a proper G3 annual inspection and you should not have wasted your time and money getting them out I the first place. I know of one landlord who was left with a £30k bill when his insurers failed to pay out because of a failed maintenance / installation instance in a block of flats where the two flats below were flooded.

UVC's are constantly losing charge in the expansion vessels, which needs annual checking and topping up, and I've seen the aftermath when owners shrug off that routine where the UVC pops and floods the house. Greater still is the fact that most are upstairs and even greater again is the fact that thy are connected to the cold mains so have an infinite supply of mains pressure water to spew out until you get home from work. 

To answer it specifically, the sheer size of the equivalent 440L cylinder? 2 x size 9 units would still fit under a kitchen / utility worktop whereas that cylinder would be roughly 1800mm high x 660mm diameter. The cost of 1x size 9 SA ( ~£1800 depending on which model ) would pay for the 440L cylinder. In 20 years the cylinder would have cost more to inspect let alone buy.