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 18 SEER 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.