Aquarian Hot water heat pump

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Glink

7 posts

Wannabe Geek

#237586 8-Jun-2018 19:59

Just had an Aquarian Hot water heat pump installed 275l outside model. Looking for anybody else who has gone down this path. The whole process has been hard and required a lot of pre prep by me with stuff all help from the supplier. The unit itself looks great and so far has heated the water. However the apparent drop in water temp according to the displayed screen seems extreme even for Dunedin in the winter. Set temp at 55 and reached then dropped to 28 an hour later after just some sink washing up?

Still got hot water to use but my issue is the unit will now remain on constantly until it reached the set temp again! I was expecting it to be more like a normal heat pump and cycle on and off before such a large drop in water temp, meaning, as said, a long recovery run time, even if there is plenty of hot water.

Is there a way anybody knows to change the start/stop settings so that the unit is keeping the temp up with a far less drop and recovery period?

Other than that energy solutions who supplied this Aquarian are poor at supplying customer information, the manual is a poorly translated thing that explains nothing and expects you to just 'know' what to do and what each mode does, If you read it you would understand.

Sure I have asked a few more questions than many might, but the responses have not been great and I feel as if I am seen as a pain, how dare I ask questions, seems to be the attitude. Trouble is nobody here in Dunedin seems to know about them, even the firm who installed it (a very large company here) had never seen one, hence my questions to the supplier as nobody else was going to show me how it all works.

Anyway the experience in terms of customer service has not been great, nor the available information. As said the unit seems to work so maybe time will tell.

Would love to hear from anybody who has one of these units or even another brand so I can check on my expectations and compare notes!

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#2032333 8-Jun-2018 20:11

where is that temp taken from? if its from the bottom of the tank then yes it could be 28 degrees and shouldn't take much to heat back up as the top of the tank will still be hot

im sure i had a manual for it somewhere but i cant find it at the moment

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JeremyNzl

356 posts

Ultimate Geek

#2032338 8-Jun-2018 20:22

I dont have one of these but some observations

Where is the temp measured the bottom of the tank. This could explain the 28 deg after removing a sink of hot water from the unit. The inrush of cold at the bottom could possibly avg to be 28deg.

A traditional element hw cylinder would switch on in this instance and run till the set point was reached at the thermostat these are normally at the bottom of the unit.

I would expect a heatpump even an inverter model to produce better efficiency at a longer run time, cycling in and out wastes energy in a refrigeration cycle.

If you dont use a cylinder of hot water a day, you could get an electrician to fit a timer to its supply to limit the time of day it runs.

Do you know how many kws of heating the hp outputs. For a comparison an element would be typically 2 or 3kw.

There should be some cga obligations re installation and setup. these would also be balanced against what was said or asked or omitted during the sales process.

But for a 2.5k ish spend at a guess I would expect better service from the retailer.

Glink

7 posts

Wannabe Geek

#2032340 8-Jun-2018 20:26

Hi Thanks for the response.yep bottom of tank which I would think is the issue as rather than make it quicker being closer to the cold water inlet the temp will constantly drop as you draw off hot and the cold floods in too, well the lower part of the tank where the sensor is. My thoughts are if the tank is 2/3 rds full off hot then it seems silly to have a sensor so close to the cold causing constant drop and unit operation.

Unit is in Auto mode has been on for 2 hours and only raised 2 degrees in that time, yes we have good hot water but the unit running constantly seems excessive.

Do you have one of these and if so what are yor thoughts on it? any advice or tips greatly welcome

Aredwood

3885 posts

Uber Geek

#2032341 8-Jun-2018 20:31

As above - if the thermostat is in the bottom of the tank. Only a small amount of hot water usage will cause a big drop in the reported temperature.

The unit probably has multiple temp sensors, it will probably only start heating when an upper temp sensor indicates a temp drop, but once started, will keep heating until the lower sensor says that it is back up to temp.

No personal experience with that model. But have done a lot of work on a 1st gen Rheem heatpump hot water cylinder. That cylinder is at a friend house, and he has had so much trouble with it, that we are going to rip out the factory controller, and stick in an Arduino to control it.

The friend got given the cylinder second hand for free.

JeremyNzl

356 posts

Ultimate Geek

#2032342 8-Jun-2018 20:36

Also like all heatpumps, the efficiency calcs and heat output will have been at some ridiculous mild temp i.e Auckland conditions.

Heat output and efficiency of hp will drop considerably in cooler conditions i.e middle of a Dunedin winter.

However should be all good for spring, summer, autumn

Glink

7 posts

Wannabe Geek

#2032343 8-Jun-2018 20:38

Hi J

unit does have a timer which we will set for daytime use. And yes I agree the inrush of cold is what is causing the temp drop at the bottom of the cylinder and hence the run times cycling as frequently and for such long run times.

heatpump input power is 0.7kw

current outside temp is 5 degrees unit is sitting at a reading of 26 degrees. As said so far hot water seems ok my issue is only with what seems to be the very long run times for shutdown.

Would love to hear from other users of similar systems

thanks for the reply

Glink

7 posts

Wannabe Geek

#2032347 8-Jun-2018 20:43

Interesting and just what I thought. I dont have silly expectations as I installed heatpumps for a living. Just surprised at the way this has been set up. I agree with others setting it up for Auckland has no reality to the South Island and Dunedin.

What is the controller you mentioned and the benefit of it?

cheers

Jase2985

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#2032350 8-Jun-2018 21:01

it has 2.8Kw of power on the heatpump and a 1.8kw electric element

COP at dry bulb 7 EN255-3 COP 2.82

looking at a different brand has a recovery rate of 50 Litres / hour at 45°C temp Rise at 5°C temp

i would say yours should be similar

what temp is the water you are getting at the tap?

Glink

7 posts

Wannabe Geek

#2032377 8-Jun-2018 22:19

Hot water use today involved washing up cups plates dinner stuff and 2.5 showers. That is all we got from the 270Ltrs before it went down to 15 degrees and became luke warm at the taps.

I realise it is cold outside here in Dunedin but still feel this is not much in the way of available water for a family of 5. Now we have to either keep the unit on all night or wake up to cold water. So far I am yet to be convinced the nearly 8 grand this has cost is worth it!

It is advertised as a quick recovery unit suitable for high use families and yet here we are. Every time we so much as wash up a dish cold water clearly enters the system and has a dramatic effect on the stored water that has taken so long to heat up!

time will tell I guess

Jase2985

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#2032412 9-Jun-2018 06:32

something is not setup right. i would have thought the electric element would have kicked in to help. it just sounds like its not heating properly.

it takes my electric cylinder with a 3kw element about 1 hour to recover from 2 showers in the morning and then about every 6-8 hours its doing a short 6-7minute top up of the temp. yours should be similar.

i had my hot water cylinder off for 2 days before we realised.

Aredwood

3885 posts

Uber Geek

#2032427 9-Jun-2018 08:20

What outside temp does the heatpump switch to electric element only?

And also curious as to your choice to get a heatpump water heater in Dunedin. As my understanding is that you have cheap power available for night rate hot water. But you would have to use more expensive day rate power to run a heatpump hot water cylinder.

Glink

7 posts

Wannabe Geek

#2032453 9-Jun-2018 10:49

Hi all

thanks for all the replies

To answer why heat pump hot water. I owned my own heat pump company for years here in Dunedin so know the tech works here in Dunedin for heating and the same will apply for a system that uses that energy for hot water.

My issue with the unit is in its design and the claims it makes as being suitable for cold climate operation as in my opinion it has not been well designed for colder areas such as Dunedin.

In terms of bang for buck a heat pump should give far better economy than a plain immersion heated cylinder and taking into account they both use the same night time power rate a saving should be seen on that front.

The unit is sold with 3 modes Auto, Economy and Heater.

My issue is that having a mode called HEATER asides to the other two implied to me that I could use JUST the electric for say the night to enable quite ticking over of the unit to keep the water to temp WITHOUT the heat pump operating at night with the noise associated with it (and at 65 db it is dam noisy for such a small unit). However this is NOT the case as the heat pump comes on in ALL the modes. Secondly you can only set the heat pump into a timer on/off mode in the Econ setting. Again why? and again a poor design as all 3 should be able to be chosen.

All of the above will probably never raise its head as an issue in Auckland but they advertise this as a unit for all but the Harshest climates and Dunedin is far from harsh!

In order for this to work in a city like Dunedin more thought needed to go into noise level of the chosen heat pump unit (my fujitsu 6kw is rated at 49 db yet this smaller unit is 65db!)

An option for electric only back up should be available to avoid noise complaints at night

Timer mode should be available for ALL modes.

The customer service needs a major overhaul as does the pre sales information and technical details. My experience of them is that 'how dare I question their design', 'stop asking us questions' 'am i getting hot water at the tap, yes, well be happy' and so on.

The design it, sell it but that's all they have done. The manual is poorly written have a read and if you can work out a way for me to sort this out great

If I had my 4 grand back again I would go a different route and will not be giving my recommendation to others on this particular firm or unit. Dont get me wrong it works and I have no doubt we will adapt to the way it operates and in the summer for sure it will work very well with a better outside ambient temp. My issue is with it's cold climate claims and HOW it has been set up. Something I can't easily change. Big claims that in MY opinion are not backed up in it's design. You could not install this in a city like Dunedin if you had a close property next door as the noise alone would cause complaint. So as a unit for a city forget it.

I blame myself for not looking further into it and working out the lack of available information was a red flag. Unlike any other brand where information is vast this has stuff all and should have made me think twice. Strange for me I trusted the hype. This I must add is MY personal experience and I am sure there are many other happy owners of the unit I have. However I can only comment on my experience and frankly it has not been great post install, it was fantastic prior to buying it but not when I needed it afterwards. Yes I admit I have asked a lot of questions but is not that my right as a customer who has been left with a unit with a poorly translated and written manual and nobody here in the city who knows a thing about how to operate them!

And this comes from a man who has installed over 2000 heat pumps!

Jase2985

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#2032454 9-Jun-2018 10:57

@Aredwood, id say it would be in the Negatives going off other brands.

you can use a heatpump on cheap night rate power which makes it even better.

noise should only be 48 - 60dB

Aredwood

3885 posts

Uber Geek

#2032457 9-Jun-2018 11:20

Jase2985: @Aredwood, id say it would be in the Negatives going off other brands.
you can use a heatpump on cheap night rate power which makes it even better.

noise should only be 48 - 60dB

The 1st gen Rheem switches to electric element at around 2-4 deg outside temp. So not all units can operate at negative outside temps in heatpump mode.

Also the COP of a heatpump water heater will never be as good as a heatpump room heater. Simply due to the temp rise required. As there is a regulation requiring hot water cylinders to operate at 60deg min to stop legionella from growing in the cylinder. If we assume a base outdoor temp of -10deg, the heatpump cylinder needs to be capable of a 70deg temp rise. While a heatpump room heater only needs to do a 35deg temp rise at the same outdoor temp.

The COP of the heatpump water heater might be low enough that lower outdoor temps at night might cancel out any savings from cheaper night rate power.

Jase2985

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#2032461 9-Jun-2018 11:37

the ones i can find graphs of have about a 2COP at -5 deg and go up to about 4ish at normal temps.

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