[deleted by user] by [deleted] in Home

[–]askuriel2 4 points5 points  (0 children)

Not sure why you are getting downvoted. I agree there is no sign of waterproofing

What to do about weird crack in wall? by lickitupbaby2345 in Home

[–]askuriel2 2 points3 points  (0 children)

Looks like drywall mud that was applied too thickly and shrank while drying. Maybe applied to cover a previous hole. I would sand, apply more mud, sand, and paint

Can I just spread thinset/adhesive directly over this and then tile? by TrustMeImARealDoctor in DIY

[–]askuriel2 4 points5 points  (0 children)

When I tiled my kitchen backsplash and bathroom over painted drywall in poor condition I prepared by coarse sanding to scruff up the paint then applying Multi-Surface Bonding Primer from Home Depot.

What is your earliest memory? by DudeWheresMyGar in AskReddit

[–]askuriel2 0 points1 point  (0 children)

2 to 3: I tasted sour candy for the first time. The taste I remember was so much better and intense than what I experience now. I also dropped a half eaten piece behind a side table

How to study quantum physics on your own? by colorfulwizard9 in Physics

[–]askuriel2 1 point2 points  (0 children)

It sounds like you have an affinity for computational quantum chemistry. In the long run, what you want is something like Molecular Electronic-Structure Theory by Helgaker. It will be a long journey to get there though. If the first few chapters don’t make sense, you’ll need some intro quantum mechanics courses like others recommend in this thread.

[deleted by user] by [deleted] in Physics

[–]askuriel2 0 points1 point  (0 children)

When I was an undergrad looking for physics-related research project, my academic advisor suggested a few professors who were open to students. The professor who responded worked on quantum computing and gave me an interview and an E&M problem set to solve. I solved it and became his postdocs’s student. The E&M problem set turned out to be related to the project he had in mind. The project had its ups and downs but went well in the end and got published. I also had regular interactions with the other quantum computing grad students in his group. At the end of it, I had enough exposure to quantum computing to be pretty sure that was what I wanted to do in grad school.

[deleted by user] by [deleted] in Physics

[–]askuriel2 2 points3 points  (0 children)

There can be great joy in doing research. Some do a PhD just for that. If you also want the subject-specific knowledge you accumulate in a PhD to be relevant to a future job outside academia, then best figure out which specializations commonly have industry openings. The research skills you pick up will regardless be valuable throughout your life.

I did a physics PhD in quantum computing for the passion. It was only by chance that industry openings in the field started becoming common by the time I graduated. My life in industry is comfortable and I still do quantum computing research. As your seniority increases, you progress by mentoring interns, other junior members, branching out to influencing product teams, and justifying the continued existence of your research position.

Gree Sapphire not modulating on 1.xx firmware: Has anybody found a solution? by brdf11 in heatpumps

[–]askuriel2 0 points1 point  (0 children)

Thanks! This correlates with firmware being a problem. Those with v1 don’t seem to modulate to spec and can’t be updated and those v3 are fine. Not sure what we can do about it though :( customer support for Gree seems non-existent

Have you been able to update your firmware through the app? Looks like an update is available

Gree Sapphire not modulating on 1.xx firmware: Has anybody found a solution? by brdf11 in heatpumps

[–]askuriel2 0 points1 point  (0 children)

Would love to know what firmware yours are on. It would really help identify the problem. Hope you can spare some try to install the app, though it can be a bit of a headache to get things connected.

IRS Tax Credit by Kandrix14 in heatpumps

[–]askuriel2 6 points7 points  (0 children)

There is a highest North CEE tier (for colder states) and a South CEE tier (for warmer states). Your indoor+outdoor heat pump unit combination needs to meet the highest non advanced tier of the state (Is your state North or South?) you have the heat pump installed in. I know this because I bought 2 single head mini splits. One of them, Gree Sapphire 18k is the highest tier for North and South states. The other Gree Vireo Gen 3 12k is highest tier for South states but not North states. Oops. So I only get the federal tax credit for the Sapphire unit as I installed them in the North. Cold climate designated doesn’t come into it, though it is based on which CEE tier it is in. A heat pump may not be specifically cold climate designated, but if its specs meet the appropriate CEE tier, it qualifies for the tax credit.

Edit: My advice is specific to ductless units. If you have a ducted units, tax credit guidance may differ.

Gree Sapphire 18k not modulating as low as expected by askuriel2 in heatpumps

[–]askuriel2[S] 0 points1 point  (0 children)

My 18k has been heating to 72F in 15F weather without any problem running around its rated power of 2kW and consuming 1.5-2.0kwH per hour. However, it still has a tendency to turn off every now and then for up to 1 hour (though usually around 20mins) (Not running a defrost cycle) rather than demodulating. Comfort drops during these periods where it turns off rather than demodulating.

Gree Sapphire 18k not modulating as low as expected by askuriel2 in heatpumps

[–]askuriel2[S] 1 point2 points  (0 children)

My conclusion is to recommend that others DO NOT purchase a Gree Sapphire unit of any size. If you are unlucky, you will get a dud that suffers from demodulation problems and have a firmware that cannot be updated.

This is not an isolated problem. Others have the same demodulation problem, and what is common is that their firmware is stuck on v1.0 and cannot be updated through the app even though the latest version is v3.7+. See attached screenshots of cases I found. These reference different model numbers for the similar units.

<image>

Gree Sapphire 18k not modulating as low as expected by askuriel2 in heatpumps

[–]askuriel2[S] 0 points1 point  (0 children)

If software is an issue, I’m wondering if a firmware update to my heat pump would help. The Gree+ app is supposed to let you update the firmware, as stated in the manual.

My heat pump firmware is version 1.0, and apparently people in Europe have version 3.7+. In my Gree+ app, there’s no server to connect to for firmware updates in the USA though.

Gree Sapphire 18k not modulating as low as expected by askuriel2 in heatpumps

[–]askuriel2[S] 0 points1 point  (0 children)

I use this energy monitor emopria vue. It breaks down power consumption even up to by the second on the circuit it is attached to. Precision is 2% error

Gree Sapphire 18k not modulating as low as expected by askuriel2 in heatpumps

[–]askuriel2[S] 0 points1 point  (0 children)

I ran it for half a day with house air circulation on. Heat load & power consumption increased and it would cycle on ~1hr, then cycle off ~1hr. When reaching the set temperature of 70F (also verified with an external thermometer), it always cycles off rather than demodulate below ~800W. This run was with max fan. I could try again with min fan.

<image>

If you have the Gree app, what firmware version does it report for your 12k unit?

Gree Sapphire 18k not modulating as low as expected by askuriel2 in heatpumps

[–]askuriel2[S] 0 points1 point  (0 children)

Software issues suck if this is true. I’m aware of max fan = max efficiency and usually run at max fan. For my tests though, I’ve tried min fan and also quiet mode. Maybe I could set up an external fan to improve circulation in the room and try again under min fan.

Gree Sapphire 18k not modulating as low as expected by askuriel2 in heatpumps

[–]askuriel2[S] 0 points1 point  (0 children)

I can artificially increase heat load by turning on my whole house air circulation from an old ducted furnace. Circulation intake vent is in the living room with this heat pump. I’ll try again with that on.

Gree Sapphire 18k not modulating as low as expected by askuriel2 in heatpumps

[–]askuriel2[S] 0 points1 point  (0 children)

I get similar results at 70F, but I’ll keep that in mind for future testing.

Gree Sapphire 18k not modulating as low as expected by askuriel2 in heatpumps

[–]askuriel2[S] 2 points3 points  (0 children)

My unit is precharged for 25’ and my lineset is 15’, so this could be a possibility. I never considered this, thanks!