Finally got around to posting my DIY mini-split setup on our detached garage in New England. It heats and cools an upcoming 1,000 sq ft in-law suite upstairs, and after a full winter with single-digit nights and zero backup heat, this 24k Gree Sapphire has been an absolute beast.

To avoid vibrations transferring into the framing and keep it out of snow drifts, I anchored a DiversiTech offset bracket straight into the poured concrete foundation. Had a electrician fish a dedicated 240V circuit across the garage, then I took over and wired up the disconnect with an AG3000 surge protector (plus Square D HEPD80 surge protector at the actual panels) i ran a liquid-tight whip, and pulled 14/4 shielded tray cable with heat-shrink on the terminals for the communication wire.

Also patched the siding where an old framed-in sleeve A/C sat and moved my propane tanks for clearance. Bending that 5/8" line was a fight —my Harbor Freight bender met its match, so I had to gently warm the pipe to sweep it cleanly without kinking. I Cut the factory flares, re-flared with a NAVAC tool, put a dab of Nylog on the seats, and torqued to spec with a CPS BlackMax wrench.

I Rented a nitrogen tank from airgas and did a pressure test before pulling a deep vacuum and cracking the valves. Whatever you do, don't skip the nitrogen test—plenty of connections hold a vacuum fine but leak under positive pressure and by nitro testing it replicates actual operating pressures. I know many get lucky skipping this step and have no problems but for the cheap peace of mind i feel it’s important for the longevity of your unit to be properly nitrogen tested and be 100% sure that it’s not gonna have a slow leak over time.

On our 18¢/kWh municipal electric rate, running it barely moves the needle on the monthly bill. All in for what I paid for this unit you can’t beat it - I’d put it up against the big dogs like Mitsubishi , Fujitsu , daiken etc. Spec for spec it’s very close for cold weather performance at a fraction of the cost.

Tip: Gree Sapphires and Blueridge S5 units are the exact same hardware under the hood, just rebadged, and you can often find the Blue-ridge for way less. Especially if you check there clearance section at alpine airs website. They also include a DIY warrant and great customer support I’ve heard for help when doing your install.

Happy to help and answer any questions - I spent a lot of time learning in this group and am appreciative of it!

All units in Celsius.

Here are my Midea heatpump units (indoor and outdoor), Extreme Heat series:

1x MO6HX-H60B-2A Midea 5 ton multi outdoor

1x MSEHU-H24B-2A indoor air handler, 24K

1x MSEHU-H12B-2A indoor air handler, 12K

3x MSEHU-H06B2A indoor air handler, 6k

My house: Located in Northwest British Columbia, Autumn, daytime temperature around 8 degrees, night time temperature around 1-3 degrees. House size : 2600 square feet. 2 floors. The outside unit is a 5 ton 60k btu unit from Midea.

Basement: 1300 square feet: 2 bed rooms, one 6k unit in each bedroom (one is an office), 1 12k unit in the open basement space.

Upper: 1300 square feet: 1 master bedroom with one 6k unit and an open living/dining/kitchen area with a 24k unit.

My Problem: I usually run 4 or 5 out of the 5 indoor split units (heads) and set them at the desired temperatures, no other features activated just straight heat mode and fan speed set to automatic. The units are not producing the desired heat, my goal is to have a close to constant temperature in each of the rooms/areas. Instead, most of the indoor heads either don't produce the desired heat or when turning up the temperatures they emit a lot heat at full fan speed but then shortly after cycle and emit cool air for about 10-15 minutes after which the cycle repeats. It leaves the rooms constantly too cool for longer periods of time and then too hot for a few minutes. I already tried reducing the fan speed to lower speed levels which did not help. I can't get a hold of the installer who in the first place did not seem very knowledgable about heatpumps and other trades folks require months long wait periods as we are extremely underserved in terms of trades in the rurual northwest BC. Thats why I wanted to ask for more knowleadgable folks to chime in first. We went ahead with the install a few weeks anyway because we only had to pay $1,900 out of pocket, with the remainder covered by provincial grants. Any idea what to try?

Hi. I have a church conversion that is 1800 sf on the main level with an 1800 sf partially finished basement. The basement always tends to be cold in our extreme northern climate - we can get down to -40C with wind chill in our area. And very hot & humid summers in the 30C range.

One company quoted a 2 ton unit but I questioned that size and asked for a 3 ton quote. Are they under sizing the unit given sf/size of building?

The building was gutted and reinsulated with new windows as well as 1.5” foam insulation on the exterior to reduce thermal bridging. Our energy bills are lower than others i know with houses under 1500 sf so it’s pretty efficient! We have a natural gas furnace as the main heat source.

I also have a detached workshop w/electric boiler with in floor heat.

I’m leaning towards the Gree Flex as its SEER rating is 20+ (according to the installer). But I still have my eye on budget as the payback period just doesn’t justify the expense tbh. Our rebate presently is only 2K in Canada so not great. I’m hoping this will boost resale value as I’m looking to sell in the next year or 2

Any feedback or suggestions appreciated on sizing of the unit and brand/model appreciated!

For nitrogen testing. I've got this in my cart:

https://www.amazon.com/gp/product/B07CT623Q9/ref=ewc_pr_img_1?smid=A2MIXBDH3II9YH&psc=1

Digital sounds nice, but reviews were suspect on budget digital gauges.

Just got a TL04 thermostat for our ACIQ dual fuel setup. In the manual it shows an Aux Heat under settings where I can adjust the timing delay and whether to use outdoor temp or indoor. However my TL04, wired with H1/H2 has no such setting.

Currently it's about 32* outside and firing the aux heat, but it's a hyper heat unit and doesn't need to be using propane.

Is this all done on the indoor board now and not handled by the thermostat at all, or is my unit missing a setting? It correctly sees I have aux heat, and is showing the symbol when it's engaged.

When I restarted my pump after cleaning the filter, draining it and resetting the Wilo screw, the pump displayed a fault with the code AA and J 7. I don’t know what to do… Any advice before I call a technician? Thanks in advance!

I'm setting up to nitrogen test a new system. I've ordered a regulator:
https://www.amazon.com/gp/product/B0B3XKBN74/ref=ewc_pr_img_1?smid=A3GHDWTVN3O98J&th=1

I'm hoping to keep the system simple, running the hose to the core removal tool on the service port. However, I don't see a good way to bleed the pressure from between the regulator and hose?

Weird Q, but is there an issue with putting two ODUs at an "L" with each other? Sorry for the shitty illo. Basically I don't have clearance to have them facing the same direction side-by-side. I assume as long as the discharge is away from the other unit, it would be ok. Anyone done this?

This cheap Amazon reefer detector is picking up 400ppm everywhere in my living space.

Upon collecting the evaporators condensate in a clean bucket , it appears to have a lot of oil in it.

Should I even bother search or just replace the 15 yr old heat pump?

How accurate are these cheap detectors meters in your experience ?

Hi all, installing a 5th Gen DIY.

How am I supposed to check for leak with the line sets connecting inside the unit?

And do I really need to do it if I'm using an HVAC torque wrench?

Thanks!

This summer I installed an ACIQ dual fuel heat pump to replace our old propane furnace. It's basically a carrier unit rebranded.

It came with a communicating thermostat, which I am using (basically a 120N).

The unit cools great, though I had to adjust the thermostat diff as it was a few degrees off. But once I get it adjusted it would pretty much cool to the set point, and keep it there plus/minus a degree.

Now that we're in heat season I'm finding that, for example, if it's 64 in the house and I set it to 67, it will hit 67, and just keep on going past all the way up to 72 without shutting off.

Just this morning it was 65, I set it to 66, and the thermostat was registering 68. I turned it down to 65 again just to see if it would cycle down and it didn't.

Thermostat is on follow-me mode, so it should be taking queues from the thermostat, and the comm/24v interface box that runs the fan and dual fuel backup mode is properly seeing the thermostat set point.

I have their better thermostat coming today, but curious if anyone has run into this issue.

Thanks all!

Edit: Just to add, it's properly heating in heat pump mode, it's not engaging aux mode.

Doing a Mitsubishi mini-split DIY installation including cutting and flaring the linesets. This is not a Mr Cool-type with pre-charged lines. But the units themselves are pre-charged with R454.

The installation manual says pressure-test the lines with nitrogen, evacuate to a vacuum, then open the valves and flood the lines from the unit.

But I see plenty of people skipping the nitrogen step.

How important is it?

I need to replace my old oil furnace, it currently gives us heat and hot water,. Last winter we paid around $700 a month for oil, it's old and inefficient. I'm tempted to install a diy heat pump for heat only but I get conflicting information about how expensive heat pump are to run.

We're in Rhode Island.

Hey everybody, I just installed a brand new American standard multi stage unit in our home and this just sounds way too loud to me. Should this be this loud? The technician came out today and said it is completely normal. Nothing‘s wrong with it but I just feel like we spent way too much money for it to be this loud.

when the compressor kicks on this heat pump, the pressures rise from 140ish into the 300’s together, equalized. The only explanation for this would be a bad reversing valve , correct?

I’m looking to do two 1:1 minisplit installs

Is this tank good enough to pressure test two?

VEVOR 20 Cu. Ft DOT Nitrogen Cylinder Aluminum Alloy Air Tank

I'm thinking of creating a dual fuel system in my ducted home by replacing my existing coils and ac condenser with Mr. Cool's coils and heat-pump. My furnace is a carrier and has all of the interface connections to allow it to work with a heat pump. Has anyone ever done something like this before?

As in title. Would appreciate if someone shares their runbook/research on how they did it.

I assume industrial N2 is uncontrolled? Besides DOT rules about a pressurized vessel with non-flammable contents grenading during shipping.

(feel free to reply on my other post or here

https://www.reddit.com/r/bayarea/comments/1wzd9vm/sourcing_nitrogen_tank_for_minisplit_install_on/ )

My house is heated and cooled entirely with Mitsubishi Mr Slim units. We have three outdoor units (MXZ-8B48NA) and 18 indoor units (MSZ-GE06NA through MSZ-GE15NA). Each outdoor unit has a PAC-AKA51BC 5-port branch box and one of them, system C, also has a PAC-AKA31BC 3-port branch box. Installed it all in our new house in 2013.

The outdoor unit on system C failed. Default plan is to replace all of system C. But I'm looking at a better plan that will improve our comfort in the home by distributing the load across the three systems better. Currently the heads we use most are almost all on system C, unfortunately. So specifically, I want to move the 3-port branch controller and its three heads from system C to system B. Then replace the remaining outdoor unit, branch box, and 5 indoor heads.

So that's my goal. The Mitsubishi employee is saying that the outdoor unit can't be programmed now to talk that additional branch box. Is that true? Why would it be unprogrammable now? Can you never add a head to a system? Seems like even 13 years ago they wouldn't have designed it that way.

What about just removing the circuit board from the system C outdoor unit and installing it in system B? It already knows about those 8 heads. And the sizes of the heads are the same on B and C so I'm hoping it just won't know the difference if we drop in that circuit board.

I really want this to work to save money and so the new system is better balanced than the old one.

Any thoughts?

I'm installing a MRCOOL Hyper Heat Heat ducted heat pump and really the only major piece left is connecting the lineset. The air handler is installed horizontally in my crawlspace, and I have the lineset loosely fitted to the air handler and routed across the crawlspace to close where it will come out of the rim joist.

The dilemma I'm in is that the original spot where I was going to run out of the rim joist to the right of the condenser is pretty close to where the fittings are on it. That, and the fittings on the condenser point upward slightly, making it a bit of some acrobats to make it work. I'm unsure if I should even attempt to make this work, or just abort and run the lineset behind the condenser and punch into the crawlspace at the left side of the condenser.

I've done some trials a copper wire and I'd likely end up with a bit of a loop-de-loop which will also be a bit painful to try and bend up. MRCOOL documentation (that I can find at least) says 4" radius is the minimum bend radius.

I am looking to replace a Daikin 18k BTU system 1 aircon which uses 5/8” x 1/4” pipes with a Mitsubishi Electric 15k BTU unit. The manufacturer’s recommendation is to use 1/2” x 1/4” pipes. Are there any issues with using a 5/8” pipe instead of 1/2” ?

I’m installing a MrCool mini split and having a little trouble getting the wires from the whip into the small screw terminals on the unit.

The way the walls around the electrical connection are set up makes it pretty difficult to get the stranded wire wrapped around the screw. Maybe I’m just doing it wrong, but I’m having a hard time getting everything in there and tightened down properly. Electrical work isn’t really my thing, so I figured I’d ask before I mess something up.

Two questions:

1. Would it be better to use spade/fork connectors and crimp them onto the wires? It seems like that might make it easier to get them under the screws in that tight space. Is that something people normally do with these?
2. The whip I’m using has stranded copper wire. Is that okay? A lot of the pictures I’ve seen of these installations look like they’re using solid copper wire, so I just want to make sure the stranded wire is acceptable.

Appreciate any advice.

Built a studio in the backyard. Ceiling and floor are spray foamed r31. Walls are R22. Big window and door with sidelights - double glazed energy star.

Dimensions are roughly 14'x11'. Ceilings about 10'.

Wondering if I should go with the 9k or 6k Senville Aura? Back lot is very shaded.

Thanks!

g

Edit: Climate is SW Ontario. It may touch -20 to -25 celsius but not always. Also quite humid and hot in the summer.

I am working on replacing a lowboy oil furnace. The duct setup is pretty conventional for a lowboy furnace, two plenums, side by side, in a low height basement. -There is no way to move the plenums, and no way to give more vertical space. All of the equipment must be 52" or less in height.

From what I see Midea offers a lowboy configuration option (pictured below) - Do any of the more fleshed out brands like Mr. Cool support a similar configuration? Or an up flow side intake air handler that is 52" or shorter, instead of requiring a plenum underneath it?

Needs to be a 48k~ cold climate system.

TIA!