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Sunamp PV killing its heaters...


MartinP
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Looks like my SunampPV killed its 3rd heating element in 2 years (and second one was on the day of replacement of the 1st one).

Its not burnt, still steady 17Ohm when cold, just leaking to the earth (about 260kOhm there) so RCD trips away.

 

As Sunamp support has the usual dislike to emails / catch-me-if-you-can phone attitude - does anyone know if it is stock item or... its Sunamp special?

Quick check shows its 2800W HLP version from https://www.tuerk-hillinger.com/products/ - but ones in their catalogue only go up to 1000W

 

At his point I'm thinking that Willis inside is a bit undersized / prone to overheating, so... would the control board cope with 3kW/11-inch element in an  external one?

 

Don't want to hack it...  but if this is the way to keep it working, so be it. I really like it, when it works.

 

 

 

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Is this a Sunamp PV? 

 

If so, then there was an issue on early models that led to two potential problems.  The primary issue seemed to be that the over-run time on the pump was a bit too short, leading to heat soak in the small heater chamber.  This could cause the resettable over-temperature cut-out to trip (I had this problem a fair bit).  The second problem was that the over-temperature cut-out on some early models had a manufacturing defect, that lead to the terminals over-heating.

 

Another possible issue could be that the heater was running at more than its rated power, due to a high local supply voltage.  This was one concern that was raised whan we were having problems with the thermal trip operating on our old Sunamp PV.  During sunny weather our local supply voltage runs right up to the maximum allowable of 253 VAC.  At that voltage the 230 VAC rated heating element will be delivering around 3.08 kW, rather than 2.8 kW.

 

I had several conversations with the Sunamp technical guru, who was very helpful at the time, and we worked through options to fix things, but unfortunately I believe that he's either left the company, or no longer communicates directly with customers (no idea why, as he was very helpful).  I have the name and contact details for their current customer service chap, that I can pass on to you by PM if you wish.  He's not quite as familiar with the technical side of their products, and may not know much about the Sunamp PV, but he does seem keen to communicate, which is a start.

 

The control board switches the heating element with a relay, and IIRC that relay has 16 A contacts.  Should be OK for a 3 kW heating element, but it's easy enough to whip the cover off and check the relay rating to be sure.  Best check the supply voltage, though, as an element rated at 3 kW at 230 VAC would be well over that at the maximum allowable grid voltage.

 

 

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5 hours ago, JSHarris said:

Is this a Sunamp PV?

Yes its the PV. 

I think the overvoltage to 248-250 is part of the problem, element is rated 2800W @230V.

 

That does not quiteexplain why the heating element would leak to earth - instead of burning out - is it simply ceramic getting wet due to leak caused by overheating/expansion of the tip of the sheath? It does looka bit like press-fit (photo of the old one) T+H 1115HLP 230V 2800W

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4 hours ago, Temp said:

260kohm equates to about 1mA leakage current. Bit low to trip an RCD? 

 

Depends when he's measuring it as to how "real" that figure is. You often have to be real quick. As a test I've measured elements causing nuisance tripping as NOT being down to earth when cold. Chucked them in a pint glass and topped up with hot water out of the kettle and watched the resistance to earth drop like a stone as the casing expands and damp gets in. Take it out, dry it off / let it cool down and the resistance goes back up. Let's face it a mere IR test can "dry out" a damp motor. Has the RCD itself been checked & ramp tested? It might have a tripping threshold of maybe 25mA...the standing protective conductor current might already be close, cumulative from other circuits and its not taking much to put it over and trip it. 

 

I'm sure Sunamp's technical department will help... ?

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I'm beginning to wish Id never heard the name SunAmp. The idea and the theory is so appealing.

The reality is niggly, piggly  lack of attention to detail. If ever there was a case for the application of boring, clumping Teutonic thoroughness and attention to detail, this is one.

Scheiße ist das alles.

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12 hours ago, MartinP said:

As Sunamp support has the usual dislike to emails / catch-me-if-you-can phone attitude 

 

Use Twitter to contact them and call out both the issue and their unresponsive support line. They tend to be a bit more responsive on there. 

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14 hours ago, JSHarris said:

During sunny weather our local supply voltage runs right up to the maximum allowable of 253 VAC.  At that voltage the 230 VAC rated heating element will be delivering around 3.08 kW, rather than 2.8 kW.

 

Nearer 3.388 kW, neglecting the slight drop in current due to increased resistance at the higher temperature.

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3 minutes ago, Ed Davies said:

 

Nearer 3.388 kW, neglecting the slight drop in current due to increased resistance at the higher temperature.

 

 

No, the Sunamp PV heating element is rated at 2.8 kW at 230 VAC, so at 253 VAC it will be a bit over 3 kW.

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The impression I have is that Sunamp have used a rapid prototyping approach when doing product development, with immature "production" standard kit being sold and then fixed in the field.  This seems to be pretty normal with some technology companies, but is a bit of an odd approach for items intended as fit-and-forget domestic products. 

 

Why people are so tolerant of products that fail in one way or another and need constant fixes from the manufacturer I don't know, but it does seem to be becoming normal.  There are lots of examples in the electric vehicle market of this approach, pioneered by Tesla who are still rolling out fixes to cars that are several years old.  My BMW is no different, the Connected Drive app is a pile of crap, that BMW keep playing around with in an attempt to get it to work better, often breaking it or reducing functionality in the process.  Even Nissan, who one might have expected to get things right first time ("right first time" was written on big signs on the production line when I visited their Sunderland plant years ago) have had to issue several firmware updates to their cars to fix really quite serious failings (#rapidgate for example).

 

On the positive side, our Sunamp UniQ eHW 9 is now working very well indeed.  The new controller and sensor array seems to be a significant improvement, with a noticeable increase in the utilisation of excess PV generation when compared to the originally supplied controller and sensor string.  The threshold at which the controller calls for heat has been significantly reduced, so that it now pretty much always calls for heat after a single shower's worth of hot water has been drawn off.  This has noticeably reduced the need for an over night E7 boost, to the extent where I could probably turn the over night boost off for now.  What would be very useful indeed would be a way to switch the over night E7 timed boost on or off from the Sunamp controller.  If there was a way of externally sensing when the controller is calling for heat, and then using this to switch the timed boost on at night, then this would remove all need for regular intervention.

 

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Frankly sunamp should be paying for @JSHarris input, us non informed humans would not have a clue. I am a bit of a Luddite, I like KISS and stuff that’s been about a bit and already had all the wrinkles ironed out , also the less technical the kit the less there is to go wrong.

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1 hour ago, JSHarris said:

No, the Sunamp PV heating element is rated at 2.8 kW at 230 VAC, so at 253 VAC it will be a bit over 3 kW.

 

For constant resistance, power is proportional to v², not v, 'cause when the voltage increases the current does too.

 

>>> (253/230) * 2.8
3.08
>>> (253/230)**2 * 2.8
3.3880000000000003

 

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27 minutes ago, JSHarris said:

The impression I have is that Sunamp have used a rapid prototyping approach when doing product development, with immature "production" standard kit being sold and then fixed in the field.  This seems to be pretty normal with some technology companies,

 

Yep, it's so standard in the software industry now that most people seem to accept it as normal. The sad thing is that the bad habits of the software industry are spreading to more hardware-based industries rather than good practices going in the opposite direction.

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used to call it "tombstone technology" in the aviation  world ,or so i was assured by a man who worked  for bristol after the war then finished on the concord project before retirement

If the wings fall off --then we need to beef them up --sort of attitude

LOL

no excuse these days with computers to work all the numbers out in a split second 

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11 minutes ago, MartinP said:

Does anyone with working, water-heated Sunamp have willingness and ability to measure & time temp profiles on the heating pipes going in & out of red cells?

 

I'm not sure who here still has a Sunamp PV installation.  @TerryE does, and I think there's at least one other member with one.  Our's went back to Sunamp in exchange for a Uniq about a year ago.

 

One snag with trying to measure those temperatures is that the pump varies it's speed in order to try and keep the temperature flowing into the batteries fairly constant.

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3 hours ago, JSHarris said:

This seems to be pretty normal with some technology companies,

I notice that when I update the applications on my Android phone, almost without exception, there is a second update within 2 days.

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59 minutes ago, SteamyTea said:

I notice that when I update the applications on my Android phone, almost without exception, there is a second update within 2 days.

I am the opposite. I won''t let my stuff auto update for no good reason,. I will update something when it either stops working properly or I feel I need a new feature.

 

If it ain't broke, don't fix it.

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I think with things like phones it is more about security, rather than new features.

Though sometimes they do a major update and the application looks and acts totally differently.  And they take away the few features I use.

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(continuing the OT discussions of software) it's also largely about compatibility with the rest of the world. Phones do not live in isolation, but are connected to all manner of web servers through to Bluetooth devices etc that are constantly changing around them.  If the phone never updated, the device will become obsolete much quicker due to being locked in time against an internet moving on with new standards and protocols and content that the old software can't access. Like the situation we had with IE4 desktop web browsers not that long ago.

Add on top the fact that it's just not economically viable to release zero defect software, providing an infrastructure that allows easy update when bugs or compatibility breaks or security flaws are found is considered the next best solution. This is basically playing to the advantage of the "softness" of software. And when done right, it's a winning strategy: 7 of the 8 biggest companies in the world are primarily SW firms, when even a decade ago there was only one in the top ten.

If you are waiting for good practices to start to flow from HW to SW engineering, you're going to be very disappointed. In my experience the reverse is very much the case with other industries trying to emulate the recent trend of "software to eat the world". 

 

And I'm not saying this to excuse it, or ask you to like it ? just being realist about where the wider industry is at.

 

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11 minutes ago, ProDave said:

Well when the "flashlight" app on my phone tells me it wants updating?

 

And WHY does the flashlight app use up some data?  Some spyware built in it perhaps?

 

Everything is collecting data, it's how most of the "free" stuff earns money. 

 

The old adage "There's no such thing as a free lunch" applies to pretty much every bit of mainstream software out there now.  What's worse, much of the time when you think you're "buying" something, the reality is that you're only renting it.  A neighbour is as angry as hell right now because she "bought" a lot of ebooks, and now she can no longer read them, as it turned out she was only renting them (although this wasn't at all clear unless you really delved into tens of pages of obscure terms and conditions).

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