Author Topic: Anyone have experience with Mr. Cool heat pumps?  (Read 2153 times)

yeti

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Anyone have experience with Mr. Cool heat pumps?
« on: December 21, 2021, 11:32:56 AM »
I'm going back and forth on whether or not to go all in on electric -- solar panels, heat pump, and electric water heater -- and ditch natural gas altogether. The problem I'm having with HVAC is that the Mr. Cool heat pump that I'd like to install (MDUO1836) only appears to be capable of upflow or horizontal orientation for the air handler while I need downflow. Does anyone have any experience with this model or type of air handler? I asked to question to Mr. Cool customer service but didn't receive any response. I'd like to be able to install myself and have had good luck with Mr. Cool mini-splits.

yachi

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Re: Anyone have experience with Mr. Cool heat pumps?
« Reply #1 on: December 21, 2021, 01:41:48 PM »
I'm going back and forth on whether or not to go all in on electric -- solar panels, heat pump, and electric water heater -- and ditch natural gas altogether. The problem I'm having with HVAC is that the Mr. Cool heat pump that I'd like to install (MDUO1836) only appears to be capable of upflow or horizontal orientation for the air handler while I need downflow. Does anyone have any experience with this model or type of air handler? I asked to question to Mr. Cool customer service but didn't receive any response. I'd like to be able to install myself and have had good luck with Mr. Cool mini-splits.

Are you sure you don't mean MDUI18036?  I see that more on a google search.  The installation manual for it says: "The return ductwork is to be introduced into the air handler bottom (upflow configuration)"

If you're asking "should I install this model in an orientation inconsistent with the manufacturer's recommendations" I'll give you a hearty heck no.  Everything from how the driptray functions, to how well the components are protected from moisture, to how efficiently and silently the blower runs could be affected.

When we first moved in to our house, we had a split system with natural gas fed heat.  The air handler or ductwork had an issue whereby the air flow was turbulent where it discharged into the main duct at the top of the unit.  The airflow was so odd, that it suspended the droplets that condensed out of the airstream, and leaked where it wasn't supposed to - missing the driptray and corroding the natural gas components.  I'm not sure how often the previous owners used the system, but we replaced it as it was 30 years old when we moved in.

yeti

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Re: Anyone have experience with Mr. Cool heat pumps?
« Reply #2 on: December 21, 2021, 02:58:40 PM »
Thanks for the response. Yes that's the same unit, I just used the model number off the Mr. Cool website

I understand that there are issues with moisture and changing direction of the drain pan, but in theory there shouldn't be a difference in swapping the fan and heat exchanger and reversing the fan direction (physically being able to do this is another story) -- other brands of AHU do allow this and even some Mr. Cool products do from what I've seen. I'm not suggesting that I would go buy one and hack it up -- I was just wondering if anyone else had experience with this model. Perhaps no DIY downflow heat pump solution exists.

yachi

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Re: Anyone have experience with Mr. Cool heat pumps?
« Reply #3 on: December 22, 2021, 07:14:27 AM »
Thanks for the response. Yes that's the same unit, I just used the model number off the Mr. Cool website

I understand that there are issues with moisture and changing direction of the drain pan, but in theory there shouldn't be a difference in swapping the fan and heat exchanger and reversing the fan direction (physically being able to do this is another story) -- other brands of AHU do allow this and even some Mr. Cool products do from what I've seen. I'm not suggesting that I would go buy one and hack it up -- I was just wondering if anyone else had experience with this model. Perhaps no DIY downflow heat pump solution exists.

It's best to find a model that works for downflow, or modify your ductwork to make it work.  I'd be hesitant about changing the direction of the airflow through the unit.  When a manufacturer does this, they then subject the unit to testing to make sure the airflow is still laminar through the unit, and water doesn't pool in weird places.  Given enough motivation, I think you could do something and have it work at least 5 years, but if you're getting a bit of moisture on a critical component, it might not make it 15 years.

uniwelder

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Re: Anyone have experience with Mr. Cool heat pumps?
« Reply #4 on: December 22, 2021, 09:06:38 AM »
What do you mean when you say you need down flow?  What's the current configuration of ducting?  Is your natural gas unit in the attic with a main return in the ceiling and a network of ducts to the various rooms?

yeti

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Re: Anyone have experience with Mr. Cool heat pumps?
« Reply #5 on: December 22, 2021, 09:35:04 AM »
It's best to find a model that works for downflow, or modify your ductwork to make it work.  I'd be hesitant about changing the direction of the airflow through the unit.  When a manufacturer does this, they then subject the unit to testing to make sure the airflow is still laminar through the unit, and water doesn't pool in weird places.  Given enough motivation, I think you could do something and have it work at least 5 years, but if you're getting a bit of moisture on a critical component, it might not make it 15 years.
I wish I could find a downflow model that works with their precharged linesets, but I'm not aware of any. The modifications I could do would be to build a duct to reverse the flow either from upflow or horizontal. I guess I could see certain things that could affect the airflow, but as long as the fan and heat exchanger are oriented the same and the return and supply duct conections are the same size there shouldn't be much difference.



yeti

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Re: Anyone have experience with Mr. Cool heat pumps?
« Reply #6 on: December 22, 2021, 09:35:52 AM »
What do you mean when you say you need down flow?  What's the current configuration of ducting?  Is your natural gas unit in the attic with a main return in the ceiling and a network of ducts to the various rooms?

My current configuration is the ducts are built into the foundation (slab on grade) so there's no modifications that can be done there. The furnace is in the garage and blows down into the ducts which also connect to the swamp cooler outside (would have to be blocked off if I install a heat pump). The air return is a single vent that goes through the garage wall into the furnace, near the ceiling obviously.

Ripple4

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Re: Anyone have experience with Mr. Cool heat pumps?
« Reply #7 on: December 22, 2021, 12:13:26 PM »
I'm going back and forth on whether or not to go all in on electric -- solar panels, heat pump, and electric water heater -- and ditch natural gas altogether. The problem I'm having with HVAC is that the Mr. Cool heat pump that I'd like to install (MDUO1836) only appears to be capable of upflow or horizontal orientation for the air handler while I need downflow. Does anyone have any experience with this model or type of air handler? I asked to question to Mr. Cool customer service but didn't receive any response. I'd like to be able to install myself and have had good luck with Mr. Cool mini-splits.

If the furnace is in the garage maybe the horizonal layout could work just build a workbench over it and have a 90deg duct shoot into the floor? alternately keep the furnace you have, put a ECM blower in and a good filter and install a few minisplits in the most used rooms then the air will move around and get filtered via the old furance. I like that Mr.cool 3kbtu deal and I also like the no-NG idea. there is youtube where a guy put in one and it only cost him ~$3xx more over the year to heat and cool, in a northen climate no less. but he saved ~8K on the DIY install.

yachi

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Re: Anyone have experience with Mr. Cool heat pumps?
« Reply #8 on: December 22, 2021, 12:23:14 PM »
Thanks for the response. Yes that's the same unit, I just used the model number off the Mr. Cool website

I understand that there are issues with moisture and changing direction of the drain pan, but in theory there shouldn't be a difference in swapping the fan and heat exchanger and reversing the fan direction (physically being able to do this is another story) -- other brands of AHU do allow this and even some Mr. Cool products do from what I've seen. I'm not suggesting that I would go buy one and hack it up -- I was just wondering if anyone else had experience with this model. Perhaps no DIY downflow heat pump solution exists.

They make a conversion kit for some other models.  You can see what it consists of here: https://www.homedepot.com/p/MRCOOL-Signature-Air-Handler-3-5-Ton-Down-Flow-Kit-MSHDK3660/314412475

Insulated drain pan
Insulated downflow coil support brackets
Insulated inner drain pan drip shields
Non-insulated outer coil slab shields
Front and rear insulated air seal plates
Tapping screws and some insulated foam tape

Insulated stuff because the drip pan water is going to be cold - you don't want air condensing on the underside of the drip pan and dripping on the blower.

You could contact MrCool and see what they would suggest instead.  See if they're considering a conversion kit for this one.

sonofsven

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Re: Anyone have experience with Mr. Cool heat pumps?
« Reply #9 on: December 22, 2021, 01:06:36 PM »
I don't have any experience with Mr. Cool; however, the pool heater I just installed has detailed instructions to change the orientation by re-arranging the internals. Have you downloaded the installation guide and read it?
Also, contact the company, and always follow the recommended install or you will void the warranty if you have problems.

index

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Re: Anyone have experience with Mr. Cool heat pumps?
« Reply #10 on: December 24, 2021, 07:15:39 AM »
Get the Midea version which allows for down flow and vacuum the linset.

https://www.minisplitwarehouse.com/product/midea-24000-btu-20-seer-central-ducted-split-hyper-heat-pump-ac

If you have installed a few mr cool diy units, you are plenty capable of commissioning the unit.  You will need a few hundred dollars worth of tools which you can resell or use again later:

$100 Vacuum pump, $130 micron Guage, $35 vacuum rated hose, $50 core removal tool, $30 blank off valve.

I would by the core tools and micron guage on ebay and you should be able to recover 80% of the cost. 

Indio

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Re: Anyone have experience with Mr. Cool heat pumps?
« Reply #11 on: July 08, 2022, 07:28:00 PM »
Hoping that someone following this thread could help with my questions since my own thread isn't getting any hits.

Haven't been able to reach customer support so I thought I'd check with all the folks who've installed Mr cool mini split ductless heat pumps.

I've got a small house so I'm limited on locations where I could install the indoor units. I was planning on installing 2, at either end, in my finished attic, but the ceilings are low and sloped. There's no way I can get the 70" required height. If I install it under a window, 24" above the wall to wall carpeting, what would happen? Would it work at half capacity? The space on one side of the attice is about 200 sq ft, so not very large.

My 2nd question is whether Mr C manufactures an indoor unit that has tubing that vents to the left side, as you look straight at it, rather than to the right. The only location in dining room, that doesn't require drilling thru a back porch, needs a left sided hole for tubing and power.

thanks for sharing your advice and recommendations.

aasdfadsf

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Re: Anyone have experience with Mr. Cool heat pumps?
« Reply #12 on: July 09, 2022, 12:36:15 AM »
Hoping that someone following this thread could help with my questions since my own thread isn't getting any hits.

Haven't been able to reach customer support so I thought I'd check with all the folks who've installed Mr cool mini split ductless heat pumps.

I've got a small house so I'm limited on locations where I could install the indoor units. I was planning on installing 2, at either end, in my finished attic, but the ceilings are low and sloped. There's no way I can get the 70" required height. If I install it under a window, 24" above the wall to wall carpeting, what would happen? Would it work at half capacity? The space on one side of the attice is about 200 sq ft, so not very large.

I just installed a mini-split (I made a recent thread about it on this subforum). It wasn't Mr. Cool, but I'm pretty convinced that they make them all in the same giant factory in China and then assemble them in another giant factory in Vietnam or wherever and then someone buys a million units and slaps their brand on them.

The indoor unit is supposed to be higher than the outdoor unit, but I can't think of a theoretical reason why that has to be other than for the water condensate to be able drain down. The coolant moves in a circuit, both up and down. Maybe it makes a difference whether the bigger line has a gravity assist compared to the smaller line? I don't know, but I would very surprised if you were to lose any noticeable efficiency from having only a 24" difference in elevation compared to 70". And if the unit is oversized for your needs, then a small loss of efficiency won't matter. The idea that you might lose half your efficiency sounds ridiculously unlikely to me, but I think that "index" knows more about this stuff, so maybe they will chime in.

Quote
My 2nd question is whether Mr C manufactures an indoor unit that has tubing that vents to the left side, as you look straight at it, rather than to the right. The only location in dining room, that doesn't require drilling thru a back porch, needs a left sided hole for tubing and power.

Again, I used a different brand, but on every single one I looked at, you can go left, right, straight back, or whatever works. You just have to bend the lines. You have to be careful when doing this because you don't want to make a kink, but they are meant to be bent. There are even knockouts on the plastic on either side that allow the lines to go through in either direction.

uniwelder

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Re: Anyone have experience with Mr. Cool heat pumps?
« Reply #13 on: July 09, 2022, 06:20:38 AM »
I've got a small house so I'm limited on locations where I could install the indoor units. I was planning on installing 2, at either end, in my finished attic, but the ceilings are low and sloped. There's no way I can get the 70" required height. If I install it under a window, 24" above the wall to wall carpeting, what would happen? Would it work at half capacity? The space on one side of the attice is about 200 sq ft, so not very large.

Are you going to use it primarily for heating or cooling?  Close to the floor is ideal for heating the space, but not great for cooling.  I've seen an installation from someone in Vermont from GreenBuildingAdvisor.com that swears by installing just above the floor.  However, that person is not concerned with cooling the space.

How big is the attic and is it all open or two closed off spaces?  200 sq ft is small for a dedicated mini split unit.  If they are two separate spaces, there are ways to connect airflow.  For example, you can buy a wall transfer fan---- https://www.sylvane.com/tjernlund-aireshare-room-to-room-transfer-fan.html that fits between wall studs and can move air between them.  That's much cheaper than installing two units in the attic.

Additionally, most companies that sell 'short ducted' mini split units.  The unit is intended to be placed in a concealed central location, like a closet or utility room, and then ducted to adjoining rooms a few feet away.  I don't know if Mr. Cool offers this.

Indio

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Re: Anyone have experience with Mr. Cool heat pumps?
« Reply #14 on: July 09, 2022, 12:02:32 PM »
thanks for the input @aasdfadsf and @uniwelder.

Will try to figure out how to configure unit to drain on right side for dining room install.

Unit is intended to provide both heat and cooling. It gets hot in that unshaded attic, during the summer, and my teen is constantly running the window unit AC in their bedroom. The attic is 2 separate spaces with a door that is mostly closed on the bedroom side.

Went with ductless because I didn't want to be crawling thru the knee wall, where I would barely fit, to add in the duct work.

Was thinking that I might be able to get it 40" high if I install it diagonally with drainage at the low point?? Not sure if this is a good idea, becuase the studs aren't ideally placed.

uniwelder

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Re: Anyone have experience with Mr. Cool heat pumps?
« Reply #15 on: July 09, 2022, 12:24:59 PM »
Was thinking that I might be able to get it 40" high if I install it diagonally with drainage at the low point?? Not sure if this is a good idea, becuase the studs aren't ideally placed.

I think its important to get the unit level.  I'm not sure what you mean about stud placement.  The wall units I've seen have a metal mounting plate that is attached to the wall first, and then the unit clips onto it.  The mounting plates were all the same width as the unit, so you should have plenty of opportunities to get at least two studs to attach to.

I didn't mention it in the last comment, but as aasdfadsf said, they've been accommodating for drainage and connections for either side of the unit.  I'm sure you download the installation manual before buying the unit to make sure.

index

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Re: Anyone have experience with Mr. Cool heat pumps?
« Reply #16 on: July 11, 2022, 10:23:01 AM »
Hoping that someone following this thread could help with my questions since my own thread isn't getting any hits.

Haven't been able to reach customer support so I thought I'd check with all the folks who've installed Mr cool mini split ductless heat pumps.

I've got a small house so I'm limited on locations where I could install the indoor units. I was planning on installing 2, at either end, in my finished attic, but the ceilings are low and sloped. There's no way I can get the 70" required height. If I install it under a window, 24" above the wall to wall carpeting, what would happen? Would it work at half capacity? The space on one side of the attice is about 200 sq ft, so not very large.

My 2nd question is whether Mr C manufactures an indoor unit that has tubing that vents to the left side, as you look straight at it, rather than to the right. The only location in dining room, that doesn't require drilling thru a back porch, needs a left sided hole for tubing and power.

thanks for sharing your advice and recommendations.

The unit is going to work no matter how high on the wall you install it. My guess is the 70-inches has more to do with people not messing with it than anything else. The intake for a wall unit is on top of the unit, so there is a minimum space needed between the unit a ceiling.

I don't know how "finished" the attic room is, but you may want to look at replacing the existing window unit with an inverter window unit. This will scale the same way a mini-split does and they are much quieter than a traditional window unit. The other option is to go with another brand that offers a floor unit. Mr. Cool sells their units as DIY because they have pre-vaced lines. By the time you get to that step, you are already doing 90% of the work; you might as well do the whole job and free yourself to pick the best unit for your application.   

As far as the left versus right situation is involved, you can punch a hold directly into the space inside the indoor air handler. The lines on most Midea manufactured units I've seen exit to the left.