Installed a 4/5 Ton Mr Cool (Gree Flexx) Heat pump

[farmwithjunk]

Last year I had 4 quotes to do a heat pump in my house which involved connecting the kitchen (had its own hvac) to the air handler and moving where the air handler would be. Went with the lowest quote and they did decent work with the limitations on duct space.

Had them out again to quote my "farmhouse" which is 3br 1.5 bath and 1800 sq feet. It has a sunroom addition which had its own 100k oil furnace for 300 sq feet. So similiar thing, needed less than 30 feet of supply/return to that room. That quote was around $13,000 which I thought was high. Got another quote and they said it would be over $20,000 to do that and then quoted $13k~ for a new oil furnace with a heat pump and coil.

Ended up going the DIY route with the Mr Cool Universal with their no-vac lines (think hydraulic fittings). Took me a few weekends and evenings to do the power, ducting (included a hole through barn stone foundation and block to sunroom).

So far its working well. Its a much better unit as far as efficiency and adaptability at 18 seer vs my 16 seer 2-stage Payne I paid to get installed. It allows up to 1.0" ESP, 8 speed settings and ramps both up and down on inside and outside units. It can run as low as 1.1KW or 15-19k btu then ramps up as needed. I did not install the heat strip as its rated down to -22 and I think 100% btu output at 5F. Including a 20# (spare/future resale) jug of r410, guages, adjustable torque wrench, the unit and all the tape/ducts/fittings I'm at less than $5800! If someone was direct swapping their existing unit I could see this being a weekend project. Also has a 10 year warranty. Time will tell if this was a good purchase but I couldn't see spending another $6,000 plus for something I could do and get a less effective unit.

 

[EbS-P]

Last year I had 4 quotes to do a heat pump in my house which involved connecting the kitchen (had its own hvac) to the air handler and moving where the air handler would be. Went with the lowest quote and they did decent work with the limitations on duct space.

Had them out again to quote my "farmhouse" which is 3br 1.5 bath and 1800 sq feet. It has a sunroom addition which had its own 100k oil furnace for 300 sq feet. So similiar thing, needed less than 30 feet of supply/return to that room. That quote was around $13,000 which I thought was high. Got another quote and they said it would be over $20,000 to do that and then quoted $13k~ for a new oil furnace with a heat pump and coil.

Ended up going the DIY route with the Mr Cool Universal with their no-vac lines (think hydraulic fittings). Took me a few weekends and evenings to do the power, ducting (included a hole through barn stone foundation and block to sunroom).

So far its working well. Its a much better unit as far as efficiency and adaptability at 18 seer vs my 16 seer 2-stage Payne I paid to get installed. It allows up to 1.0" ESP, 8 speed settings and ramps both up and down on inside and outside units. It can run as low as 1.1KW or 15-19k btu then ramps up as needed. I did not install the heat strip as its rated down to -22 and I think 100% btu output at 5F. Including a 20# (spare/future resale) jug of r410, guages, adjustable torque wrench, the unit and all the tape/ducts/fittings I'm at less than $5800! If someone was direct swapping their existing unit I could see this being a weekend project. Also has a 10 year warranty. Time will tell if this was a good purchase but I couldn't see spending another $6,000 plus for something I could do and get a less effective unit.

How does the ramp up/down work? If it isn’t satisfied, after so many minutes, it ups the output?? I’m correct that these are non communicating? It would be nice if one could control the ramp based on temp or at least change the time so that one could get longer run cycles for better dehumidification

 

[GrumpyDad]

Last year I had 4 quotes to do a heat pump in my house which involved connecting the kitchen (had its own hvac) to the air handler and moving where the air handler would be. Went with the lowest quote and they did decent work with the limitations on duct space.

Had them out again to quote my "farmhouse" which is 3br 1.5 bath and 1800 sq feet. It has a sunroom addition which had its own 100k oil furnace for 300 sq feet. So similiar thing, needed less than 30 feet of supply/return to that room. That quote was around $13,000 which I thought was high. Got another quote and they said it would be over $20,000 to do that and then quoted $13k~ for a new oil furnace with a heat pump and coil.

Ended up going the DIY route with the Mr Cool Universal with their no-vac lines (think hydraulic fittings). Took me a few weekends and evenings to do the power, ducting (included a hole through barn stone foundation and block to sunroom).

So far its working well. Its a much better unit as far as efficiency and adaptability at 18 seer vs my 16 seer 2-stage Payne I paid to get installed. It allows up to 1.0" ESP, 8 speed settings and ramps both up and down on inside and outside units. It can run as low as 1.1KW or 15-19k btu then ramps up as needed. I did not install the heat strip as its rated down to -22 and I think 100% btu output at 5F. Including a 20# (spare/future resale) jug of r410, guages, adjustable torque wrench, the unit and all the tape/ducts/fittings I'm at less than $5800! If someone was direct swapping their existing unit I could see this being a weekend project. Also has a 10 year warranty. Time will tell if this was a good purchase but I couldn't see spending another $6,000 plus for something I could do and get a less effective unit.

Keep us posted on how this works. I considered their mini splits and this solution for our cabin. Im concerned about service long term though.

 

[farmwithjunk]

How does the ramp up/down work? If it isn’t satisfied, after so many minutes, it ups the output?? I’m correct that these are non communicating? It would be nice if one could control the ramp based on temp or at least change the time so that one could get longer run cycles for better dehumidification

Non communicating thermostat is correct. I have an ecobee with the differential set at 1.5F so when it does run it will run longer. These mild temps it will short cycle. I have min off time as 20 minutes and min run time the same. Once it actually gets cold I think it will run much longer. I'm getting almost 100F out of the vents and assume this is at it's lowest setting.

The condenser does have dip switches to control standard or efficiency mode and defrost strength as well.

My understanding is the condenser starts at the lowest setting and uses the outside temp as well on how hard to run. After 20 minutes it will start to ramp up. This is not in the manual or anywhere that I can find though. The air handler starts slowly too, and ramps up over a minute or two to the max setting via dip switches. I'm running .6 ESP at the default setting of 6 (of 8).

 

[farmwithjunk]

Keep us posted on how this works. I considered their mini splits and this solution for our cabin. Im concerned about service long term though.

They are made by Gree who is the (or one of) largest HVAC equipment producers in the world and Mr Cool has been around for over a decade. Parts are available to consumers and they do seem to have a good warranty from reading people's experiences getting entire condensers sent as replacements. I could replace this twice over and still be ahead than having paid an HVAC company to do it.

The HVAC crowd hates Mr Cool and hate homeowners doing their work. They crap all over Mr Cool and talk about warranty...but their own warranty is usually only for a year, huge lead time on parts and even if the part is covered under warranty their labor and refrigerant is not.

The Mr Cool Hyper Heat even includes 10 year LABOR warranty but I'm not sure if that requires a license HVAC tech to complete the lines or not. The unit I got is covered by homeowner install IF you get the no-vac lines. Makes sense, you almost eliminate the contamination and potential for leaks with nitro purging/brazing.

 

[EatenByLimestone]

I’m strongly considering going this route too. I was considering (2)1 ton units, 1 for each floor.

I’d like 1 for a cabin too, but that’s further down the line.

How did you coil the extra line? Did you place them so they would be out of the way of snow fall?

 

[farmwithjunk]

I’m strongly considering going this route too. I was considering (2)1 ton units, 1 for each floor.

I’d like 1 for a cabin too, but that’s further down the line.

How did you coil the extra line? Did you place them so they would be out of the way of snow fall?

I got the 15' lines so really no extra. I bolted it down to cinder blocks sitting on concrete pavers. Just don't want snow build up around it. We don't get enough to worry about more than 6-8". Mini split probably the way to go with a cabin if it isn't very big.

 

[begreen]

Kudos for the self-install. Do you have some pictures of the installation? I look forward to hearing more about the unit performance over the winter.
Can you provide a link to the components installed.

 

[farmwithjunk]

Kudos for the self-install. Do you have some pictures of the installation? I look forward to hearing more about the unit performance over the winter.
Can you provide a link to the components installed.

Used this system then the no-vac lines:

MRCOOL Universal Series 4 Ton 17 SEER2 Ducted Central Air Inverter Heat Pump Split System

The MRCOOL Universal Unitary Heat Pump system is an easy to install, full size air handler with a slim condenser, suitable for most 4-5 ton applications. This system is incredibly flexible, combining the ultimate in ducted comfort and easy installation.The 5 ton condenser can be field converted...

hvacdirect.com

I already had a 20x25x5 filter box from my other house which I re-used.

Its not the prettiest setup since I re-used everything that I could and made the return airbox from wood and the supply from duct-board. I didn't want to deal with bending tin.

Other costs were new breakers and 8 gauge wire, tape and 75' of 12" insulated duct to connect the other room.

I was limited on room without re-doing the panned off return since furnaces are side return and air handlers are bottom return.

 

[begreen]

One thing I don't like in this unit is the low coils location. The air handler configuration is the opposite of ours which has the blower low and the coils up above it. That makes hooking up to a condensate pump and the return easier.

I'm trying to figure out how you solved this issue. Is the return plenum made of wood? Is the filter box half-open?

For best performance our system is entirely sealed and insulated, including supply and return plenums, trunk ducts and branches. There's a lot of heat loss in uninsulated ducts.

 

[farmwithjunk]

One thing I don't like in this unit is the low coils location. The air handler configuration is the opposite of ours which has the blower low and the coils up above it. Is the return plenum made of wood? Is the filter box half-open?

My Payne has the coil above the fan.

Yes, I made the return box out of wood. I've sealed things up since the picture but its tight.

 

[Zack R]

@farmwithjunk
How has the Mr Cool unit been performing this winter?

 

[farmwithjunk]

@farmwithjunk
How has the Mr Cool unit been performing this winter?

Its doing great. The house has no insulation in the walls so that certainly does not help. I turn it down when I'm not there renovating but it heats up well enough. It can still pump out 100F air when its around freezing. Not sure what kind of algorithm it uses to ramp up because the air never seems to be much hotter regardless of outside temp so it is modulating at some capacity.

My ecobee (via Beestat) shows that it can heat down to -17F based on the data it has gathered. That is impressive when many people still say heatpumps don't work below freezing.

 

[DBoon]

That is impressive when many people still say heatpumps don't work below freezing.

Just goes to show that you can't believe many people, but you can believe data.

-17 degree F heat pump performance has been around at least 8 years, probably more. I installed a Fujitsu with this capability about that many years ago and it is still going strong, after having been moved to a different house.

 

[begreen]

farmwithjunk, can you give an update after another winter's use? I am considering this setup and may self-install. What is the coldest weather it has seen?

Does this system have resistance heat coils installed? If yes, have they ever kicked in?

 

[farmwithjunk]

@farmwithjunk, can you give an update after another winter's use? I am considering this setup and may self-install. What is the coldest weather it has seen?

Does this system have resistance heat coils installed? If yes, have they ever kicked in?

It was good down to around 3 and could maintain and at -12F it started to lose heat. That's with no insulation in the bulk of the walls which I had blown in cellulose done this spring to r15.

Data so far shows a little over half the heat loss after insulation.

No backup coils. I'm thinking with the insulation it should be good below zero.

 

[Turbo89]

Just goes to show that you can't believe many people, but you can believe data.

-17 degree F heat pump performance has been around at least 8 years, probably more. I installed a Fujitsu with this capability about that many years ago and it is still going strong, after having been moved to a different house.

Another bump - was this the “hyper heat” or equivalent version rated down to -38F or just the “regular” version. I’m debating these for heat and AC in a climate that sees -20 in the winter at least a handful of times.

 

[begreen]

Thanks for the quick update. I'm looking at about $5000 for this setup + 15' linesets. Have to do some measurements to see how much will be involved replacing the current Am. Std. system.

 

[begreen]

I note that HVAC Direct is pushing the ACiQ systems in a search.

 

[Whitenuckler]

Its doing great. The house has no insulation in the walls so that certainly does not help. I turn it down when I'm not there renovating but it heats up well enough. It can still pump out 100F air when its around freezing. Not sure what kind of algorithm it uses to ramp up because the air never seems to be much hotter regardless of outside temp so it is modulating at some capacity.

My ecobee (via Beestat) shows that it can heat down to -17F based on the data it has gathered. That is impressive when many people still say heatpumps don't work below freezing.

In have two heat pumps. One is old and barely makes heat when it's cold (-10C ect). The other is newer and does OK below -10C. As a heat pump has to "move" or extract the heat from the air, there is not much heat available when it's below -10C. They all cannot work as well. They are great though. I like the idea of having a heat source that makes heat which is why I got a pellet stove (also I can run the pellet stove without utility power)

 

[begreen]

Actually, there is quite a bit of heat still in the air at that temperature. The problem may be that the heat loss of house exceeds the capacity of the system, but that is a different issue. This is the case with our house. It has too many large windows and just average insulation. When we get into the mid-teens, the heat loss is high. For this reason, we are looking into a system that will output 36,000 BTUs at -10C.

 

[Whitenuckler]

Actually, there is quite a bit of heat still in the air at that temperature. The problem may be that the heat loss of house exceeds the capacity of the system, but that is a different issue. This is the case with our house. It has too many large windows and just average insulation. When we get into the mid-teens, the heat loss is high. For this reason, we are looking into a system that will output 36,000 BTUs at -10C.

That one old unit I have simply does not work well anymore. It was routed to the basement, and even if I had it set for 22C, the basement would go down to 16C. That area is not too hard to heat so it was just sucking power. I since moved the head to my bedroom, and I'm loving it again in cool mode. I took out extra insurance in case it fails.

 

[Highbeam]

Actually, there is quite a bit of heat still in the air at that temperature. The problem may be that the heat loss of house exceeds the capacity of the system, but that is a different issue. This is the case with our house. It has too many large windows and just average insulation. When we get into the mid-teens, the heat loss is high. For this reason, we are looking into a system that will output 36,000 BTUs at -10C.

I sized mine this way too. To make sufficient heat when it's cold outside. The drawback of course is that the other 90% of the time the heat pump is quite oversized. No real problem with that if you're okay with the thing cycling more often. Some efficiency loss, a little harder on the equipment, and higher equipment cost.

To make the above sizing method even sillier is that we heat with wood when it's cold so the heat pump sized to heat at low outdoor temperatures will always be oversized unless the wood heat is not operational for some reason. Like an emergency.

 

[begreen]

Our needs are changing. We will likely be burning less wood in the next 5-10 yrs if we live that long. If one of us gets sick, then the system needs to carry the load, not the wood stove. I have to decide on whether to just use the resistance coils at that point or have a heat pump that can carry the load. Additional AC will also likely become more necessary. We use a portable auxiliary unit in the master br now. It would nice to have this more permanent and with it's own zone. I could do a mini-split for there, or do a split system off of the ducted setup. Right now just getting ideas and estimates.

 

[EatenByLimestone]

Age is why I was looking into them. Right now a window ac works fine, but as I get older, it m not sure I’ll want to put them in and take them out. As it is, once out I don’t want to bring them downstairs to the basement to store. I don’t see too many years before I don’t even want to take them in and out anymore. My main issue is my house has small enough walls in general that the interior cassettes take up too much room. They need say 36” to fit, I have 33” available.