disappointed of lincolnshire Sunamp - new label showing only C rated energy efficiency

[Jeremy Harris]

FWIW, the Sunamp PV controller had built-in web connectivity, via a GSM board, so they've gone backwards with the control unit for the UniQ range.  Also, the Sunamp PV had external LED indicators that displayed power on, solar detected, charging and flow detected.  These were very useful.  Not knowing whether or not the UniQ is accepting charge or not was one of the major failings initially (until I added an indicator light to show when the contactor was on).

[ProDave]

2 hours ago, JSHarris said:

Inside the unit it's clear that the 16 A power only connects to the contactor, and then goes back out to the heating element.  There's no connection from this supply to the control board. 

Devil's advocate.

 

Bypass the contactor.  You can almost guarantee your excess PV diversion will start up at a low power as the sun comes up / goes round so the heat input will be gentle at first rising throughout the day, so the fear of an initial high power input into a solid mass of cold PCM would not be there.

 

Of course anyone doing such, would never admit to it on a public forum.... 

[Jeremy Harris]

20 minutes ago, ProDave said:

Devil's advocate.

 

Bypass the contactor.  You can almost guarantee your excess PV diversion will start up at a low power as the sun comes up / goes round so the heat input will be gentle at first rising throughout the day, so the fear of an initial high power input into a solid mass of cold PCM would not be there.

 

Of course anyone doing such, would never admit to it on a public forum.... 

 

The snag is that it then needs an over-temperature cut out of some sort.  The contactor and controller sensing does that function, and it's critical to ensure that the PCM doesn't reach around 120°C, where it starts to decompose.

 

I may just implement my timer fix later, as I'm getting fed up with waiting for some sort of resolution from Sunamp.  I have a DIN rail mount time switch, with SPCO contacts, that's programmable down to 1 minute on or off periods.  By using the NC contact and setting the timer to switch "on" (really off) for 1 minute at 08:00 each morning I can emulate what I've been doing by turning the power on and off to reset the controller.  The time switch only needs to switch the low power circuit, not the main supply to the heating element.

[paulmb]

From what 'we' know, does the 50/90% charge threshold issue apply to all configurations that are heated from the internal electric heater?  

[Jeremy Harris]

18 minutes ago, paulmb said:

From what 'we' know, does the 50/90% charge threshold issue apply to all configurations that are heated from the internal electric heater?  

 

Yes, it seems to, as all seem to use the same control system.

 

I've yet to hear anything from Sunamp to say that there is any control unit available that doesn't refuse to accept charge until the unit is around 50% discharged, although they have stated that the 50% figure is approximate.

 

My best guess is that the "50%" is based on the centre thermistor reading, so the control logic assumes ~50%, but only when discharging, when the centre sensor reaches a particular temperature reading, probably close to the phase change temperature of 58°C.  This is just guesswork, though, based on observed performance.  I can measure the input energy to the Sunamp, as I fitted meters to both the boost and PV diverted power supplies, so I know that it sometimes (about 30% of the time) refuses to turn on when ~4 to ~4.5 kWh has been drawn off.  As the nominal capacity is about 9 to 10 kWh, and allowing for a bit of standing heat loss (maybe around 0.4 kWh) it seems that, at least in our case, the threshold is pretty close to being 50% discharged before any charge will be accepted.

[Barney12]

48 minutes ago, JSHarris said:

My best guess is that the "50%" is based on the centre thermistor reading, so the control logic assumes ~50%, but only when discharging, when the centre sensor reaches a particular temperature reading, probably close to the phase change temperature of 58°C.  This is just guesswork, though, based on observed performance.  I can measure the input energy to the Sunamp, as I fitted meters to both the boost and PV diverted power supplies, so I know that it sometimes (about 30% of the time) refuses to turn on when ~4 to ~4.5 kWh has been drawn off.  As the nominal capacity is about 9 to 10 kWh, and allowing for a bit of standing heat loss (maybe around 0.4 kWh) it seems that, at least in our case, the threshold is pretty close to being 50% discharged before any charge will be accepted.

 

My energy meters provide the same sort of values so I'll agree your best guess.

[Russdl]

15 hours ago, recoveringacademic said:

but this thread causes me to do more than dither.....

 

You and me both!

[Barney12]

Just resurrecting this thread as I'm just finalising my 'as built' SAP rating. 

Has anyone actually got the 'final answer' as to what the energy assessor inputs in his calcs for a Sunamp unit?

 

I'm trying to make things simple by proving the answers in advance to save a lot of 'bank'n'forth' with the online assessment company. 

 

[Jeremy Harris]

17 minutes ago, Barney12 said:

Just resurrecting this thread as I'm just finalising my 'as built' SAP rating. 

Has anyone actually got the 'final answer' as to what the energy assessor inputs in his calcs for a Sunamp unit?

 

I'm trying to make things simple by proving the answers in advance to save a lot of 'bank'n'forth' with the online assessment company. 

 

 

Just treat it as a hot water cylinder of equivalent capacity with the standing loss that is in the Sunamp data sheet.  The energy efficiency rating of the Sunamp is a bit of a red herring, in my view, and it now seems they all have an ErP A rating.

 

For example, a 9 kWh Sunamp has an equivalent water heat capacity of 212 litres and a standing loss of 0.738 kWh/24h, so those are the figures I'd put in to the SAP worksheet.  The heat loss rates and equivalent water heat capacity figures are in this table:

 

[Barney12]

Thanks @JSHarris I've supplied that info.

 

Rob

[TerryE]

Ours likewise and in terns of heating ours just classed ours as a resistive heater (immersion element).

[stubiff]

Do we know if this sensor/controller issue has been sorted out?

Thanks.