A2A DIY Install

[S2D2]

I have now fitted this unit so if anyone has any queries drop them in here and I'll try to provide answers. I'll do an update once I have some usage figures too.

[HughF]

Ooh, interesting.... I'm still very tempted to get one just for the learning experience

[S2D2]

5 hours ago, HughF said:

Ooh, interesting.... I'm still very tempted to get one just for the learning experience

Yes it was put in as an experiment really in ASHP's in general and A2W vs A2A.

 

Some early notes:

1. The product delivered was actually eiQ-12WMINV-V4, though the user guide linked on the store page is V3. I can't see any obvious differences other than a couple I came across installing. The V4 manual states 100mm clearance is needed above the internal unit whereas the V3 manual states 250mm. Also the V4 data sheet shows a minimum room size which the V3 does not.
2. I've uploaded the V3 installation manual for interest as it's not available on the site
3. I used a 65mm diamond tip core drill with an SDS plus drill with safety clutch. The clutch kicked in when the brick core separated along a mortar join as i reached the internal hole from outside, up a ladder, so I wouldn't recommend drilling without a safety clutch.
4. The pipes, wire and drain actually fit through a 50mm drainpipe which I used as a sleeve inside the 65mm hole, packed externally with strips of pipe insulation and siliconed in. The manual mentions the sleeve and packing but none are supplied with the unit
5. There is very little space behind the internal unit for the pipes, drain and wire so avoiding a tight bend on the coolant pipes means the bottom of my unit sits several mm proud of the wall. It may be possible to improve this by trimming insulation as the unit can be pushed flush with force or it may just be the design of the bracket, I'm not sure.
6. The internal unit is charged, I presume with nitrogen, so once the internal work is complete you can be confident there isn't a leak as there is a release of pressure when the plastic pipe caps are removed
7. You have to use the supplied 3m pipe extension even if not required as it has two female ends, converting the internal unit's male end
8. I used a hand vacuum pump as per this video: https://www.youtube.com/watch?v=2RDfAkmDId0 - The unit can be installed without a vacuum pump and my hand pump only reached -26.5 rather than -30 so I did one flush of coolant as described in the installation manual. I have no idea how much better this is than just doing the three flushes without vacuuming at all as per the instructions so it can probably be skipped
9. The unit seems to be able to modulate down to 400W input from it's nominal 1.2kW then starts cycling on/off to reach lower gains. I've been running it between 400-800W so far
10. The wifi module uses the Tuya smart app, which has a Python library here: https://pypi.org/project/tinytuya/ - Some customisation is needed for the data registers which I can upload if required but this allows control of the unit via Python, so I intend to put together a more intelligent control system using this. The input power seems to be some function of set temperature and difference between set temperature and current temperature so combined with tracking power draw via a smart plug this could be adjusted to divert solar export without any expensive hardware and with a high CoP. This needs to be coupled with heat requirement modelling to prevent overheating.

Hopefully that helps those interested.

Installation Manual V3.pdf

[S2D2]

Some data on the install now that I have 32 days worth, for those interested:

1. Modelled heat demand for that period was 1518kWh. This probably has a 10% error margin as it's just a multivariate regression of heating data before the ASHP went in
2. Actual gas usage in that period minus estimated hot water usage was 475kWh. If anything the hot water estimate is likely to be pessimistic
3. ASHP usage in that period was 200kWh
4. So on average every 1kWh the ASHP used offset between 4.5 and 5.2kWh of gas
5. 65-70% reduction in gas heating usage from the install of a single minisplit unit
6. Assuming 90% boiler efficiency that gives a CoP estimate of 4.1-4.7, which compares well to the data sheet SCoP of 4.2
7. Minimum daily CoP estimate of 3.1, maximum of 6.1. There's been a good range of temperatures over this period to see behaviour over a real heating season, though obviously performance will be lower in winter months: Daily mean: 7.0°C Max: 10.9°C Min: 1.2°C. Lowest reading -4°C

That's probably all the data I'll get for this heating season as we're getting into large solar gains from the conservatory which invalidates the heating model.

 

Since moving to Octopus Flux everything the heat pump has used has effectively come from PV due to the import/export symmetry. So we've had ~1MWh of free heating from the solar panels, which sort of blows my mind. That's effectively paid back ~18% of the installed ASHP cost in one month.

 

I couldn't be happier with the results of this little experiment, they've lined up perfectly with expectations. For balance, a few downsides of going with a cheap unit:

1. The indoor unit housing is cheap and plasticy, but not offensively so
2. Horizontal fan sweeping is manual only and no fancy occupier avoidance features like on the pricer brands
3. Only the low fan speed is very quiet and the auto mode tends to have weird peaks of high fan speed when starting up etc.
4. The outdoor unit has a slight vibration resonance in the housing, I have it well out the way so not an issue but I may add some damping pads at some point to eliminate it

The Tuya wifi integration is a great little bonus and I have a control system written with the Python bindings for much finer control on scheduling which makes best use of the Flux tariff.

[Radian]

On 11/04/2023 at 16:20, S2D2 said:

The Tuya wifi integration is a great little bonus and I have a control system written with the Python bindings for much finer control on scheduling which makes best use of the Flux tariff.

Nice work! I wonder how fine-grained you can make the control for use as a PV diverter load? To balance import/export to zero means working within 1000J or less (450J in the case of my utility meter) so you would need to run at minimum modulation for mere seconds. I doubt this would be possible or desirable.

I guess a more approximate approach based on bulk energy monitoring against a minimum export threshold would be better than nothing. I've been experimenting with this but it's nowhere near as accurate as dumping mains cycles into an immersion load.

[joth]

Thank you @S2D2 for sharing all your findings with this. I bought one, arrived yesterday, for DIY install in my gym/garden room currently being built. I plan to do it without the vacuum pump, just follow their alternate instructions for commissioning.

At some point I'll try and hook the Tuya API from my Loxone system, but tbh we don't really intend to use it often so that won't be a huge priority.

Hypothetically, if I bought it through my own company I could provide it to my household as a VAT zero rated supply and install service 🙂

[S2D2]

1 hour ago, Radian said:

Nice work! I wonder how fine-grained you can make the control for use as a PV diverter load? To balance import/export to zero means working within 1000J or less (450J in the case of my utility meter) so you would need to run at minimum modulation for mere seconds. I doubt this would be possible or desirable.

I guess a more approximate approach based on bulk energy monitoring against a minimum export threshold would be better than nothing. I've been experimenting with this but it's nowhere near as accurate as dumping mains cycles into an immersion load.

I had considered this but it's not responsive enough without a huge buffer to avoid import - it certainly couldn't guarantee no export. The start up from cold cycle takes about 15 mins where it runs things harder to get everything up to temperature, but even a change of temperature of 1 degree whilst running takes about 30 seconds to a minute to stabilise on the power graph, here's a change from the boost temperature during Flux cheap hours to the normal temperature:

 

 

Note also three minutes later the temperature sensor must have dropped a degree and it modulates back up, so very fine control is not possible. Coarse modulation between 400-800W should be possible as a function of several variables but as the CoP stayed above three and I have a small battery I've never looked into it further as everything just works. It runs 2-5am on boost, then 5-13 on the morning Flux battery charge + PV, 13-16 on boost before turning off for the 16-19 peak period and back to normal operation with the last bit of battery after that.

 

It also plays a little jingle when you change a setting (fine for larger time periods, but every second?) so that'd need locating and removing!

 

1 hour ago, joth said:

Thank you @S2D2 for sharing all your findings with this. I bought one, arrived yesterday, for DIY install in my gym/garden room currently being built. I pla  to do it without the vacuum pump, just follow their alternate instructions for commissioning.

At some point I'll try and hook the tuya API from my Loxone system, but tbh we don't really intend to use it often so that won't be a huge priority.

 Hypothetically, if I bought it through my own company I could provide it to my household as a VAT zero rated supply and install service 🙂

 

No problem, good luck with your unit, I'd be interested in any performance figures but maybe we're a little late in the heating season now.

[markocosic]

Great job! 🙂

 

Especially on taking control of the thing via tuya. 

 

fwiw I've found the vac pumps from "vevor" perfectly adequate for a handful of installs/reinstalls.

[andyscotland]

3 hours ago, joth said:

 

 Hypothetically, if I bought it through my own company I could provide it to my household as a VAT zero rated supply and install service 🙂

Hypothetically, HMRC would probably want to see a reasonable charge for the labour to justify that it was a genuine supply & fit rather than supply only. And you'd then suffer a corporation/income tax hit on getting that back out of the company, so it wouldn't work out quite as much of a saving.

[saveasteading]

1 hour ago, andyscotland said:

Hypothetically, HMRC would

..probably be all over you thereafter too, asking for proof of everything.

 

You might even lose out using the hypothetical method if the virtual vat inspector decided on a high installation cost, then both charged and fined you.

[HughF]

Very tempted to install one of these to provide a little evening heat in the house, without needing to light the second wood burner. I think the battery/inverter system wouldn’t have an issue running it, if those are the typical energy consumption figures.

[Nickfromwales]

On 14/02/2023 at 13:25, Dillsue said:

We have a propane back up boiler in the centre of the house with no concerns about 47kg bottles of gas connected to soldered gas pipework. Much lower pressure but the connected volume is massively more.

With a Gas Safe Registered installer and certificate?  

[S2D2]

On 12/04/2023 at 22:15, markocosic said:

Great job! 🙂

 

Especially on taking control of the thing via tuya. 

 

fwiw I've found the vac pumps from "vevor" perfectly adequate for a handful of installs/reinstalls.

Thanks, I think I'd seen your recommendations on those before and tried to get one but there seemed to be a complete lack of stock of the cheaper electric pumps when I checked at the time, not sure why. The hand pump was probably not worth the hassle given the manufacturer has instructions for an install without pump. It'd be interesting to know the effect on performance to know whether the electric pump is worthwhile or not but the manufacturer doesn't provide any clues.

[markocosic]

11 hours ago, S2D2 said:

Thanks, I think I'd seen your recommendations on those before and tried to get one but there seemed to be a complete lack of stock of the cheaper electric pumps when I checked at the time, not sure why. The hand pump was probably not worth the hassle given the manufacturer has instructions for an install without pump. It'd be interesting to know the effect on performance to know whether the electric pump is worthwhile or not but the manufacturer doesn't provide any clues.

 

I think the vendor will be in the business of selling these rather than ensuring that they live a long and happy life. Vac pump is as much for drying out the lines by boiling off any moisture under vacuum as it is for purging air. I'm sure it'll work fine though.

 

I should add the ask no questions tell no lies minisplit kit to the tool loan page come to think of it. Vac pump, cutting too, flaring tool, cheapo gauges good only for checking vacuum/hooking up the vac pump. Annoying to post though as it'll barf out all the oil in the vacuum pump is tipped over and it'll take an age to drain it dry dry. Might have to be local only/hand relay only.

[S2D2]

On 16/04/2023 at 20:13, markocosic said:

Vac pump is as much for drying out the lines by boiling off any moisture under vacuum as it is for purging air.

Something I didn't achieve at 26.5 as the boiling point would have still been around 50°C, whoops. Probably a complete waste of time unless you know your hand pump can hit 30 then!

[Dillsue]

On 15/04/2023 at 23:39, Nickfromwales said:

With a Gas Safe Registered installer and certificate?  

Nope. Don't beleive its required for self install. Just have to be competant. 

[Nickfromwales]

12 hours ago, Dillsue said:

Nope. Don't believe its required for self install. Just have to be competent. 

Guesswork, and wrong, I'm afraid.

 

On 14/02/2023 at 13:25, Dillsue said:

We

This is where the self-install "competent" people fall down.

 

You can kill yourself, that is permissible and you won't get prosecuted posthumously, but, you cannot cause the death of others, and that includes your unsuspecting family members.

So, unless you live alone, and have the only key to all the doors, and can prove no innocent 3rd parties will suffer from your mis-adventure, you CANNOT work on gas in your home.

End of.

[SteamyTea]

7 hours ago, Nickfromwales said:

End of.

Almost.

I think it is down to who the Health and Safety Executive deem to be competent, and they currently only accept it is Gas Safe registered fitters.

[markocosic]

The HSE believe that domestic gas safe folks* are competent? 🤣 

 

*Even the ones in nationally branded colourful vans?

 

In the real world you can fit your gas appliances if you deem yourself competent and don't make an unsafe installation. Enforcement is, by choice, nil other than failed domestic gas safe monkeys doing bad installs for cash and idiots stealing copper/bypassing gas meters.

 

Even shoddy firms putting incompetent folks to work in multiple homes in nationally branded colourful vans don't get sanctioned.

 

Ever.

[Nickfromwales]

7 hours ago, SteamyTea said:

Almost.

I think it is down to who the Health and Safety Executive deem to be competent, and they currently only accept it is Gas Safe registered fitters.

Yes, that’s the foundation assumption. Self ordained lunatics bend this rule and try to justify that there is a loophole they can negotiate around. 
Idiots. 

[SteamyTea]

1 hour ago, Nickfromwales said:

Idiots

idiōtēs Greek for ones own.

 

[Nickfromwales]

17 hours ago, SteamyTea said:

idiōtēs Greek for ones own.

 

On one’s own, more like!

[Miek]

10 hours ago, Nickfromwales said:

On one’s own, more like!

One of my favourite Welsh phrases.. 'He's on his own' 🤣

 

[Nickfromwales]

2 hours ago, Miek said:

One of my favourite Welsh phrases.. 'He's on his own' 🤣

 

“Who’s coat is that jacket” is a close second. 👊😎🏴󠁧󠁢󠁷󠁬󠁳󠁿🏴󠁧󠁢󠁷󠁬󠁳󠁿🏴󠁧󠁢󠁷󠁬󠁳󠁿

[markocosic]

Tidy lovely innit.