Mini split install questions/suggestions

jeopardy98 · Oct 10, 2015

I have pretty much decided on a MrCool DIY 2 ton ductless heat pump setup for my garage area. My original plan was to purchase this in about a year so I had the electrician do a run with 10/3 and install a dedicated 30 amp breaker for the mini split. I originally thought I would just run the lineset right out the back into a wall mounted compressor so that I wouldn't have an ugly lineset on my new vinyl siding but now I'm not so sure.

The mini split comes with a 16' lineset which means I will have to coil the set. Also I'm not sure that wall mounting is the best idea at this point. Should I just mount it to a pad? Could I offset the inside and outside unit just enough to coil the lineset inside the sheetrock?

Do I have to have a junction box since the compressor will feed the inside unit and I already have a dedicated breaker? If so since I already paid the electrician to pre-wire for a mini split shouldn't he come back and do that once the siding is on?

Is it okay to run the lineset and drain tube inside the wall? The sheetrock is up but the vinyl is not so I could remove a piece of the exterior sheathing and install the lineset that way.

Am I overthinking this all? Should I just run the lineset down the vinyl and cover it with vinyl gutter protector?

Any and all help from those of you who have done this is appreciated. Comments, suggestions, or concerns are welcome too.

walrus · Oct 10, 2015

jeopardy98 said:
I have pretty much decided on a MrCool DIY 2 ton ductless heat pump setup for my garage area. My original plan was to purchase this in about a year so I had the electrician do a run with 10/3 and install a dedicated 30 amp breaker for the mini split. I originally thought I would just run the lineset right out the back into a wall mounted compressor so that I wouldn't have an ugly lineset on my new vinyl siding but now I'm not so sure.

The mini split comes with a 16' lineset which means I will have to coil the set. Also I'm not sure that wall mounting is the best idea at this point. Should I just mount it to a pad? Could I offset the inside and outside unit just enough to coil the lineset inside the sheetrock?

Do I have to have a junction box since the compressor will feed the inside unit and I already have a dedicated breaker? If so since I already paid the electrician to pre-wire for a mini split shouldn't he come back and do that once the siding is on?

Is it okay to run the lineset and drain tube inside the wall? The sheetrock is up but the vinyl is not so I could remove a piece of the exterior sheathing and install the lineset that way.

Am I overthinking this all? Should I just run the lineset down the vinyl and cover it with vinyl gutter protector?

Any and all help from those of you who have done this is appreciated. Comments, suggestions, or concerns are welcome too.

You have to have a outdoor disconnect for the outdoor unit. Also for the indoor unit but some places aren't enforcing that.

jeopardy98 · Oct 10, 2015

If the indoor unit is powered by the indoor unit wouldn't the outdoor disconnect suffice?

fabjunkie · Oct 10, 2015

I think I'm leaning towards the MR. Cool DIY 24k myself. Get this for the lineset. Cheaper than Ingrams has them. Amazon has a cheaper wall mount too ($25) but the reviews say that you get about 8" max from the unit to the wall. This may be the same distance as the $59 wall mount from Ingrams. Ingrams looks better and easier to install as well.

fabjunkie · Oct 10, 2015

I haven't seen anything about a disconnect for the inside unit, just the outside.

zmaxmotorsports · Oct 10, 2015

Shorten/flare the line set to whatever length you need.

jeopardy98 · Oct 10, 2015

zmaxmotorsports said:
Shorten/flare the line set to whatever length you need.

I was worried that would screw up the quick connect fittings and potentially void their warranty.

walrus · Oct 10, 2015

fabjunkie said:
I haven't seen anything about a disconnect for the inside unit, just the outside.

NEC requires it

walrus · Oct 10, 2015

zmaxmotorsports said:
Shorten/flare the line set to whatever length you need.

Some manufacturers have minimum line lengths, also max but.....

jeopardy98 · Oct 10, 2015

What is the minimum space needed for a 90° turn in a lineset? Also what is minimum diameter of a full coil in a lineset?

zmaxmotorsports · Oct 10, 2015

jeopardy98 said:
I was worried that would screw up the quick connect fittings and potentially void their warranty.

All the ones Ive seen use flared fittings,do you have a picture of them?

zmaxmotorsports · Oct 10, 2015

walrus said:
Some manufacturers have minimum line lengths, also max but.....

Thats why you adjust the amount of freon in the system.
You need to check the pressure in the system and adjust the amount of freon accordingly,no matter what the length of the lineset.

walrus · Oct 10, 2015

zmaxmotorsports said:
Thats why you adjust the amount of freon in the system.
You need to check the pressure in the system and adjust the amount of freon accordingly,no matter what the length of the lineset.

I don't know **** about a Mr cool unit but you charge by weight on the ductless systems I've Been around. But they are variable speed compressors so pressures will depend on load, indoor and outdoor temps.

Not sure I'd want excess line set coiled up but I've heard of it being done

jeopardy98 · Oct 10, 2015

zmaxmotorsports said:
Thats why you adjust the amount of freon in the system.
You need to check the pressure in the system and adjust the amount of freon accordingly,no matter what the length of the lineset.

This is a complete DIY install. System is precharged and the lines have quick connect fittings. Nothing more than hand tools needed for the install and the warranty remains valid. This is why I don't want to shorten the lineset.

walrus · Oct 10, 2015

jeopardy98 said:
This is a complete DIY install. System is precharged and the lines have quick connect fittings. Nothing more than hand tools needed for the install and the warranty remains valid. This is why I don't want to shorten the lineset.

So you don't evacuate line set and indoor unit after install?

zmaxmotorsports · Oct 10, 2015

walrus said:
I don't know **** about a Mr cool unit but you charge by weight on the ductless systems I've Been around. But they are variable speed compressors so pressures will depend on load, indoor and outdoor temps.

Not sure I'd want excess line set coiled up but I've heard of it being done

All condensors are factory charged by weight as a baseline(except dry condensors),But you still have to check the running pressure of the system and adjust things from there.
What do you do when the system is a little low on freon 5 years after its installed? :wtf:

zmaxmotorsports · Oct 10, 2015

jeopardy98 said:
This is a complete DIY install. System is precharged and the lines have quick connect fittings. Nothing more than hand tools needed for the install and the warranty remains valid. This is why I don't want to shorten the lineset.

So how do you know the system is running correctly without putting a set of gauges on it and checking the pressures?

zmaxmotorsports · Oct 10, 2015

walrus · Oct 10, 2015

zmaxmotorsports said:
All condensors are factory charged by weight as a baseline(except dry condensors),But you still have to check the running pressure of the system and adjust things from there.
What do you do when the system is a little low on freon 5 years after its installed?

You' re supposed to evacuate and weigh it back in, fujitsu, Mitsubishi daiken, these are the ones I'm familiar with

jeopardy98 · Oct 10, 2015

walrus said:
So you don't evacuate line set and indoor unit after install?

Nope

zmaxmotorsports said:
So how do you know the system is running correctly without putting a set of gauges on it and checking the pressures?

I have no idea.

jeopardy98 · Oct 10, 2015

Here is the unit I'm considering.

http://ingramswaterandair.com/mrcool-seer-ductless-minisplit-heat-pump-p-22721.html

brewchief · Oct 10, 2015

walrus said:
You' re supposed to evacuate and weigh it back in, fujitsu, Mitsubishi daiken, these are the ones I'm familiar with

This, every mini-split I've seen in recent years has been charge by weight only with an amount given to add per foot for linesets over specified length.

Having a charge port only on the suction line makes it tough as well on a txv system.

zmaxmotorsports · Oct 10, 2015

jeopardy98 said:
Nope

I have no idea.

zmaxmotorsports · Oct 10, 2015

jeopardy98 said:
Here is the unit I'm considering.

http://ingramswaterandair.com/mrcool-seer-ductless-minisplit-heat-pump-p-22721.html

I bought a commercial package unit from ingrams water and air one time for a small grocery store.
They told me it would be there in a week or less,took closer to 6 weeks for it to arrive.
When it did finally arrive they sent a 3t unit instead of the 5 t I ordered.
Ecomfort has much better service.

Jackfre · Oct 11, 2015

zmaxmotorsports said:
All condensors are factory charged by weight as a baseline(except dry condensors),But you still have to check the running pressure of the system and adjust things from there.
What do you do when the system is a little low on freon 5 years after its installed?

You carefully measure and record the installed line set length on the inside of the condensing cover at the line set. In five years if things are low and you need to recharge, the factory service dept will tell you to evacuate the system, triple evacuate, nitrogen purge (oh yeah, find the leak) and weigh in the proper new charge of 410A. Your gauges will tell you when the system is off, but only the scale will tell you when it is right. That is all according to Fujitsu.

If you have extra line-set length, do not "coil" it. Doing so traps oil in the loops. Lay the line set off in a serpentine fashion.

jeopardy98 · Oct 11, 2015

Jackfre said:
You carefully measure and record the installed line set length on the inside of the condensing cover at the line set. In five years if things are low and you need to recharge, the factory service dept will tell you to evacuate the system, triple evacuate, nitrogen purge (oh yeah, find the leak) and weigh in the proper new charge of 410A. Your gauges will tell you when the system is off, but only the scale will tell you when it is right. That is all according to Fujitsu.

If you have extra line-set length, do not "coil" it. Doing so traps oil in the loops. Lay the line set off in a serpentine fashion.

Does it matter how many bends there are as long as it isn't "coils"? Is there an advantage to wall mounting vs mounting on a pad? I'm going for a clean install.

Jackfre · Oct 11, 2015

I wall mount all of mine. In my experience it keeps them cleaner, makes it harder for snakes and other critters to get into them, and if using them for heat it is easier for the water to drain off in the defrost mode. Also, the manuf like the condensing units to be level. With frost heave and all they can get knocked around. Roof mounting is good too.
You have to know the manuf spec on line sets. Fujitsu has min and max line set lengths. When ,I have weird routing and worry about kinks, etc I'll strip off the insulation, and slide a spring bender along the tubing making the bends as I go. It can be really hard and frustrating. Number of bends isn't a problem, but I do long radius bends too.

fabjunkie · Oct 11, 2015

jeopardy98 said:
Here is the unit I'm considering.

http://ingramswaterandair.com/mrcool-seer-ductless-minisplit-heat-pump-p-22721.html

Have you bit the bullet yet? This is the one I'm leaning towards also but using two of them. I just can't figure out for sure if I could get away with a couple 18k units instead. I'll have a bit bigger space to cool/heat though, 36x50x12 with open ceiling.

jeopardy98 · Oct 11, 2015

I'm planning to call tomorrow and ask a few questions. I'm pretty sure that call will end with an order. Going to use a 4" vinyl dryer vent for the exit of the lineset. Wall mount the compressor right where the lineset exits.

fastjohnny · Oct 12, 2015

If you want this brand, I'd much prefer this unit for better efficiency: http://ingramswaterandair.com/mrcool-premier-seer-ductless-minisplit-heat-pump-p-22730.html
I think you are paying a premium for a less efficient unit due to the precharged lineset and quick connect fittings.
Flaring and evacuating the system is not that difficult, I'd definitely recommend it, that way you are not locked in to a set line length.

I prefer misubishi hyper heat models, but they are more expensive.

jeopardy98 · Oct 12, 2015

fastjohnny said:
If you want this brand, I'd much prefer this unit for better efficiency: http://ingramswaterandair.com/mrcool-premier-seer-ductless-minisplit-heat-pump-p-22730.html
I think you are paying a premium for a less efficient unit due to the precharged lineset and quick connect fittings.
Flaring and evacuating the system is not that difficult, I'd definitely recommend it, that way you are not locked in to a set line length.

I prefer misubishi hyper heat models, but they are more expensive.

You are probably right but that unit requires a licensed HVAC person to evacuate the system. My guy wants $500 for that. I'm also paying more for the unit and the yearly difference in energy costs is about $75 so it would take me 8-10 years to recoup the cost difference. That unit also has a minimum 16' lineset.

jeopardy98 · Oct 15, 2015

Just an update. I ordered the 24K DIY unit and it should be here next Wednesday or Thursday. I'll update this thread with some pictures when I install it.

jeopardy98 · Oct 15, 2015

Well I called today and the builder can't get a CO until I permit this and have it inspected. $155 permit. Geez.

buzz4041 · Oct 17, 2015

bummer. Hope it works out for ya

justinjoyal · Oct 17, 2015

Jackfre said:
You carefully measure and record the installed line set length on the inside of the condensing cover at the line set. In five years if things are low and you need to recharge, the factory service dept will tell you to evacuate the system, triple evacuate, nitrogen purge (oh yeah, find the leak) and weigh in the proper new charge of 410A. Your gauges will tell you when the system is off, but only the scale will tell you when it is right. That is all according to Fujitsu.

If you have extra line-set length, do not "coil" it. Doing so traps oil in the loops. Lay the line set off in a serpentine fashion.

The reality is that, if out of warranty, most customers will prefer paying for the call and a little amount of gaz... And you can't really blame them.

If a system has been working fine for 5 years, it means the leak is tiny. A top-off will cost less than 100$ and most likely last them another 5 years...

Evacuating, triple evac, nitro purge, vacuum, charge... It all costs a lot more and from my experience customers can very well live with that tiny leak.

jeopardy98 · Oct 17, 2015

I ordered this Thursday and tracking info says the delivery driver will be here Monday. We shall see.

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