home made heatpump
 

Few years ago I made an air to water heatpump.
I used a 1400 BTU/H minisplit outdoor unit and connected it to plate heat exchager, added carel uchiller controller and it worked just fine.
After some 10 years as heat pump and it was old allready when i istalled it compressor burned.
So i simply bought a new Gree 7500 BTU mini split and connected it. I got it to work. Just I have to have indor controller connected for outdor unit work.
Is there any way to controle outdor unit with some controller?

Thanks for an answer
Matic

Please let us know exactly what you have. brand and model numbers of equipment you plan to use, the more specific the better. You said little about what the purpose of the machine is. Heating? Hot water? Heating and cooling?

I only use it for heating. It could be used for cooling to but i have radiators installed. I use it for heating till outside temperature is about -5 then i start heating with pellets.

I have gree minisplit LOMO 70 indor unit: GWH24QE outdoor unit: K3DNB6G.

I get what I want from it. Water temperature is about 50 degrees which is enought for me.
I only have I problem with electronics outdoor unit wont work without indor unit.
So i had to connect indor controller. I placed intor heat exchange sensor at the end of condenser set room temperature to 30 degrees so that unit will not stop because of room temperature. When the water temperature get to 50 degrees i simply use thermostat to swich off power fro unit. It means that compressor work at full power all the time.

I am asking if there is some kind of comtroller to make uotdor unit work without indoor unit to get propre controls.

Matic

inverter compressor drive
heat pump water heater control

Jeff, as I recall, you bought these units to integrate into a project you were working on.

I don't recall seeing posts on further developments...

How did it go?

-AC

Nope, just encouraging others to try something similar. I bought a QD-U12A control and transplanted it into an old-school, twisty knob, ton and a half window a/c. It lives at my son's house now. He rents, and the existing HVAC system is horrible.

http://ecorenovator.org/forum/geothe...it-system.html

http://ecorenovator.org/forum/geothe...onversion.html

I haven't seen the thing defrost in person, but my son said it's purring away like it should. He says it works better than the one ton unit I had running off the Arduino and an ICP defrost control. He says he knows when it does because the fan motor turns off and it goes WHOOSH! When it terminates defrost, everything shuts off for a minute or two, then it goes right back to heating.

Besides the control board and plumbing in a reversing valve, the unit is the same as it was. The old controls unplugged and the control board plugged in. Since it has a shared motor for both fans, I didn't connect anything to the outdoor fan control relay. It's not a super-high efficiency model, but it was headed for the scrap heap before I found it due to rust and dust. If my son ever gives it back, I might experiment with it. For now, it's living its second life.

Thanks for answer
does anybody know how communication between indoor and outdoor unit work.

I believe that different brands might have different comms.. At least on the older models.
On my Sanyo outdoor unit main board, there is a set of pins called 'T-Run'.
when I wanted run the outdoor unit without the indoor unit, I plugged
a switch across those two 'T-Run' pins..

When my 4-way valve default was in the wrong direction, I unplugged it's power and got the cooling out-put I wanted..
http://ecorenovator.org/forum/geothe...project-2.html

~~~
The main board got zapped last winter. If ever it's repaired, I may try
using the Outdoor unit as a hotwater heater.. I would use the T-Run pins..

Maybe you have some similar maintenance mode connection on your Gree.?.

Thanks for answer
It doesnt have test mode switch.
Now since it is winter and we nead heating at home i will live it as it is since it work (i am not wery happy with the way it work but we have heating in house). In spring I will see if i can hack signal.
It is a long time since i was doing anything on electronics and it may be interesting.

Matic

There is a member here called Aquario and I think he might have been working
on the MS protocol at one time. It's been a long time. Maybe you can find some of his posts.
He does a lot of heating with old MS outdoor units..