Mini Split Question

[tstaude]

I have done some research on an auxilary heating and cooling system for two upstairs bedrooms, and I have came to the conclusion that a mini split should take care of the job.

So here is the situation, we have two bedrooms (about 10 x 12 each) and a joining closet (3 x 12) in between the two rooms with a door at opposite ends for access from each room. We will be in this house at most 5 more years, so least investment possible is what I am after.

The current HVAC system has no returns, so the upstairs is never as cool as downstairs. The mini split would just have to be an auxilary unit to cool an extra 10 degrees in the summer and warm an extra 10 degrees in the winter to make it more comfortable. (we just use a window shaker and a space heater that work great, but now that lil man is walking it is a safety issue.)

So with that being said my question is if a single mini split in the closet in between would suffice? Both rooms have ceiling fans, and the closet doors are usually open.

Any positive input would be much appreciated!

Tom

 

[theoldwizard1]

Some manufactures make ducted interior units that are designed just for this type of application. Just have a duct that dumps into both rooms.

I would also check into the cost difference of a true dual zone unit.

A properly sized mini-split will handle it. The key is "properly sized". You will need an expert to figure that out. The only issue may be where to put the thermostat.

 

[tstaude]

So i finally got the unit up and running over the weekend! Had a good friend do the vacuum/charge so i know it was done right. It worked great for three days.....

Now when set on auto it will turn on the compressor OR the fan on the inside unit, never both. Tried reset on the remote, same thing.

Any ideas? Everything works but not simultaneously, no trouble codes either.

It is a goodman Msh122e19ax mini split heat pump and a/c unit.

Thanks,
Tom

 

[e-tek]

I hope you get more replies to your most recent post than you did in your first one....

You likely will, as I'm guessing you negated about 80% of the replies you may otherwise have gotten by ending your initial query with this sentence:

Any positive input would be much appreciated!

 

[JakeKohl]

Have you let it run for a while and see? I was concerned that mine were not working properly at first - they behave a little differently than you might expect. In heat mode, mine preheat for a few minutes before the indoor unit activates.

Also, when in heat mode, the indoor unit stays on at a very low speed so it can keep sampling the air and getting a good indication of the room temperature (the ambient thermocouple is located inside the unit) ...so it's normal for the indoor unit to be moving a little air while the outside unit is off.

Here's how my LG units work in heat mode:

temperature in room satisfied: outdoor unit off, indoor unit on a very slow speed with the air diverter directed straight down at the floor.

temperature needed in the room: outdoor unit starts to move at a slow speed, indoor unit closes off the air diverter and stops the fan (it's in preheat mode so that when it starts blowing air around the room, that air is warm). Once the coils have reached temperature in a few minutes, the indoor unit comes alive, the air diverter opens to the room, and the indoor unit fan comes up to a normal speed.

 

[tstaude]

I did let it go overnight set at 70, and it just ran the compressor. When I turned up the temp the compressor shuts off and the fan turns on and blows cool room temp air.

When we installed, it took maybe a minute after the compressor started for the fan to start and blow warm air. I can turn it up to 75 and the compressor still stays off and just blows cool air.

 

[JakeKohl]

I did let it go overnight set at 70, and it just ran the compressor. When I turned up the temp the compressor shuts off and the fan turns on and blows cool room temp air.

When we installed, it took maybe a minute after the compressor started for the fan to start and blow warm air. I can turn it up to 75 and the compressor still stays off and just blows cool air.

It's hard to say because it worked once but doesn't now - but I wouldn't run it anymore until you get a chance to thoroughly trace and prove correct termination of all of the communication and electrical wiring.

 

[JakeKohl]

This is a dumb question...but you are sure that it's in heat mode and not cooling mode - right? You might want to try cycling it through the different modes to make sure the remote and the system are all on the same setting.

 

[tstaude]

I did try in both heat and auto mode, my installer recommended auto.

It has four modes: heat, cool, auto, and fan.

The Goodman tech line is no help either, they don't want to deal with consumers.

 

[monkeyspanners]

Try it on heating and in cooling mode and see if it works.

 

[JimL]

Sling blade : it ain't got no gas...


Prolly a leaky flare. Only problem we have ever had with mini splits is install issues.. Bad flares ect....

 

[JakeKohl]

Sling blade : it ain't got no gas...


Prolly a leaky flare. Only problem we have ever had with mini splits is install issues.. Bad flares ect....

Duh...yeah. That's about the only thing that makes sense. It worked before and now it doesn't. Your buddy needs to put his gauges back on it. Sounds like it has a leak.

FYI, I don't like mine in "auto" - I found that the temperatures swing too much between heat and cool. However, mine are a different brand (and I don't think they make the Goodman).

 

[tstaude]

I am thinking you guys are right, I will let you know how it works out when I get him back over.
We did have to adapt a stub of 3/8" line onto the end of the 1/2" line. For some reason the inside unit had a 3/8" fitting on 1/2" line.

 

[Jackfre]

I am confused on your line sizing. You should only run the size specified by the manuf. Otherwise, you do not know what the right refrigerant charge is. The proper sequence for you is to recover all the remaining charge. Pressure test with Nitrogen and check for leaks, evacuate the system and then weigh in the correct system charge. There is no way to charge accurately other than by weight.

 

[JakeKohl]

I am thinking you guys are right, I will let you know how it works out when I get him back over.
We did have to adapt a stub of 3/8" line onto the end of the 1/2" line. For some reason the inside unit had a 3/8" fitting on 1/2" line.

That sounds unusual.

 

[tstaude]

Duh...yeah. That's about the only thing that makes sense. It worked before and now it doesn't. Your buddy needs to put his gauges back on it. Sounds like it has a leak.

FYI, I don't like mine in "auto" - I found that the temperatures swing too much between heat and cool. However, mine are a different brand (and I don't think they make the Goodman).

You guys were right, no gas!
A couple months back I finally tore it down and found a line with a tiny crack above the compressor.
So the update is that the retailer sent me the new unit and it works awesome! I keeps all 3 bedrooms upstairs very nice and cool.

I just wanted to give a final update for those who may read this in the future. Having the unit in the closet of two adjoining rooms works better than I ever thought!