mini split heat pump replacement advice
My Fujitsu 9RLS3H heat pump (installed in 2018) has a leak somewhere. The tech ruled out the flared connections at the outdoor unit. While it’s possible there’s a leak at the indoor connection, he thinks it’s more likely inside one of the units. Further troubleshooting to narrow it down will cost $600. Unfortunately, it’s 1 year outside of the parts warranty. (I have now learned that the length of the parts warranty is what really matters; a longer compressor warranty is basically a marketing trick).
So I have the option of repair, buying a new heat pump from the service company, or buying something online and installing it myself. I’m torn. With the Fujitsu, I went the full service, brand name route and it didn’t really pay off. A year after I bought the Fujitsu, which services my main floor and is the primary heating device, I bought a private label brand for the upstairs, which became the main device for cooling. I paid a small fraction of what the Fujitsu cost, and it’s still going after 5 years. However, its heating performance is definitely a tier below the Fujitsu, so that’s a concern for installing one on the main floor. I’ve almost ruled out the repair route, because why pay half of what a new one costs and miss out on a warranty? I could also set it aside and try to find the leak myself later on, when I have my workshop completed, and if I’m lucky I get a free heat pump for the workshop.
I’m just curious how other people would proceed. I’ve attached the performance data and prices for the various options. For reference, the design temperature for my house was 0F, and when I selected the Fujitsu I graphed its performance over temperature against the expected heating load of the house (based on a straight line from the calculated load at the design temperature down up to about 50F with no load), and the Fujitsu matched it pretty well. So if a new unit falls short of that at 5F or -5F, I may end up having to use backup heat. I do have backup heat, but it’s straight electric so kind of pricey to operate.
(sorry for the poor legibility of the image; that’s something the site did to it. If you copy the image location and paste it in a new window, when you zoom in you can read the numbers, barely)
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
Here's a copy of the excel file.
thank you for sharing
To my ear the $600 leak search sound like I don’t want to work that hard.
Find another contractor have them inject UV dye in the system and the next time the system stops preforming have them come back and find where the dye had been deposited and that is the source of the leak.
Generally, the most likely spots are the field connections. Did he check the indoor field connections?
The next most likely failure is the indoor coil that often are unrepairable. There is some chance that new heads are compatible with your current outdoor unit.
Is this the first time the system needed refrigerant added?
The leak could be tiny and go 6 years between recharges and almost impossible to locate or a new leak that will drain the system in days that is easy to spot.
If they add any inside the warranty period one could claim the leak is under warranty.
To be fair the tech could easily spend 4 hours looking for a leak with a sniffer and bill you $600 without finding the leak.
Have you looked at the MR COOL DIY units? They have connectors that allow anyone to install the unit without ant special tools or training. Note not all MR COOL units have the DIY fitting.
Walta
I may try to find another guy to do the dye thing. This guy said he can't just refill it knowing it will leak out again, because it's against the law to do so. Maybe that's true, maybe it's not.
Mr. Cool doesn't have any suitable offerings. I searched the entire NEEP product listing for anything even remote close to what I'd be replacing, and their name didn't show up. I don't know that I'd pick it either way. Sure, I don't have to make any connections, but I have to find a place to put a huge coil of unneeded tubing, while insulating it and protecting it from the weather. Wouldn't you have to, or at least shouldn't you, vacuum the lines before releasing the refrigerant? At which point, how much harder is it to just make some flared connections?
I went with a budget mini split for a studio. It mostly works but definitely doesn't put out as much heat (blows warm when those -10c or bellow hits) and has issues with occasionally icing up. I wish I spent the couple bucks more and got a better unit.
I would look at LG, Gree or Midea hyper heat units. The cost is not much more than the Senville and you get much more heat. I've recently replaced a dead no brand with a Midea hyper heat at my cottage, works great.
As for the pinholed unit, I have a 12k Fujitsu in my basement waiting on similar diagnostics.
I just searched the NEEP product list for those brands. There isn't a Gree that looks significantly better than the Senville. All the LG look worse. I found a Midea that looks good, the DLCPRBH09AAK. Where would I buy a Midea in Ontario? I have a feeling there is no such place.
edited to add:
I found a place in the US, and based on the USD price there, it's going to come out to at least double the cost of Senville, without installation and without a warranty. At that point I might as well spend a bit more to get the Mitsubishi.
further edit:
I took a longer look at the specs of the Midea, and it's not really that great. Decent heat at low outdoor temps (though still not as much as the Mitsu or Fuji), but the COP in the most important temperature range is pretty awful. 2.17 at 17F is one of the worst I've seen.
Some of the US distributors will ship to Canada but you have to deal with customs. Easiest is to ship to a PO box on the US side and pick it up.
I think the Midea 9 and 12 are the same unit so the 12 will have worse COP. Maybe look at 18k unit.
I've also noticed more Samsung units installed around me, might be worth a look.
Generally a hyper-heat unit will have lower COP than a non-hyper heat. The price you pay for higher temperature air supply. Whichever unit you go with, make sure it has a base pan heater, definitely needed here.
“This guy said he can't just refill it knowing it will leak out again, because it's against the law to do so. Maybe that's true, maybe it's not.”
To my ear this sounds more like I don’t want to look for a leak just buy this new system already.
In the US our law say they must repair bigger leaks but it only applies to large systems as I recall.
The first recharge is part of a leak test the way I see it.
MR COOL does offer “Olympus Hyper Heat” vapor injection just like everyone else but not as a DIY
The DIY line sets come in 25 foot lengths so the excess is never huge.
The line sets come “precharged” but grom the sound it made when I opened the valve my guess is the line sets and indoor units are shipped under vacuum.
Would you happen to have open cell spray foam in your home? It has been suggested open cell foam and evap coil leaks are corelated.
Walta
I have no spray foam in the house.
I looked into MRCool. It's almost as expensive (only 10% less) than the vastly superior performing Mitsubishi, has half the warranty length, and obviously means a significant amount of work for me. If I allow for 4 hours of installation labour cost in the Mitsubishi quote, then the parts cost is actually the same as MRCool, which is pretty nuts.
Edited to add: I found a cheaper source for the MRCool, so that it's about 1/4 less than the Mitsubishi. Still not what I'd consider cheap enough to warrant the performance difference, extra work and shorter warranty.
I'm going to find someone willing to do a dye injection. Before that, I may pull out the indoor unit and do a soapy water test on the fittings while it's running.
A refrigerant leak at a fitting is usually quite easy to spot. For r410a systems there’ll be a dark oily residue that smells sort of sweet—refrigerant oil that gets pushed out. If you put a pressure gauge on the service port and the system still has pressure, it’s likely a small leak. If it’s completely depressurized, it’s likely the kind of leak you’ll be able to find easily.
I’ve seen a couple of flares that I think failed years after installation. The only explanation I can come up with is that vibration and temperature cycling fatigued the copper in a flare that is already work hardened from the process of flaring. I think it was 1/4” tubing both times.
I had one installation with leaks on multiple indoor units. The evaporators showed corrosion —green copper staining on the plastic around the drain pan and pinhole leaks in the coil. The holes were obvious—the system was completely depressurized and it whistled under pressure. I was advised by Mitsubishi that this was an environmental issue. They were good about covering parts but labor was significant. What caused it is a frustrating mystery. I figured either spray foam off gassing or maybe a reaction with the chemistry of those dang plug-in air fresheners. The technical term is formicary corrosion.
Anyway, hope that’s helpful and good luck.