Mini Split in very hot area

[marsh1]

I have been looking at a Fujitsu mini split and the manual says the indoor operating range is 64-90. My AC guy says that is common. I don't really want to keep it on all the time but here in Houston the garage can get well above 115 inside all summer. Anyone have a problem with the protection circuit shutting a unit down?

Thanks

 

[79firebird]

It should be fine. I have a friend in mexico that has 6 total. 3 floor house with 2 rentals and no probs. been installed and running for 3 years

 

[lzenglish]

As long as the unit size is correct for the maximum design conditions, you will be fine! Keep in mind, that our troops are using units well beyond this range, and even into the 125-130 degree O.A. design condition range. Do as much as you can to shade, and or cover your Condensing unit, as this is where the brunt of the HVAC load is expelled, from the operating system.

Wayne

 

[pseudorealityx]

As long as the unit size is correct for the maximum design conditions, you will be fine! Keep in mind, that our troops are using units well beyond this range, and even into the 125-130 degree O.A. design condition range. Do as much as you can to shade, and or cover your Condensing unit, as this is where the brunt of the HVAC load is expelled, from the operating system.

Wayne

Shade the condensing unit? Sure.

Cover it? No, it needs as much airflow as possible, and you want to avoid it recirculating air it just expelled back into the inlet side.

Biggest thing is to make sure you take into consideration the de-rate you get with very high outside air temps. The mini-split manufacturers typically give you data with a ~95 degree outside temp. Going up to 110, 115, 120... you're losing a significant amount of that rated capacity.

Also... if the inside of your garage is getting to be 115, you need to insulate.

 

[Jackfre]

It will work fine. It will attack the latent heat (humidity) first and run at a lower speed to do so. As the latent comes down it will go after the sensible heat. The 64-90 are the ranges you can set the stat to. Keep in mind that the remote is not actually a t-stat. It is a communication device. The actual sensing element is strapped to the coil.

 

[sunny2cool]

though it says 64-90 i guess it will be fine and wont create any prblems.... u can very well go with it as long as unit size is correct for maximum design conditions...

 

[hughfree]

It will work fine. It will attack the latent heat (humidity) first and run at a lower speed to do so. As the latent comes down it will go after the sensible heat. The 64-90 are the ranges you can set the stat to. Keep in mind that the remote is not actually a t-stat. It is a communication device. The actual sensing element is strapped to the coil.

Just the opposite...the unit will primarily drive sensible temp down until dew point is reached. At this point your unit will provide sensible and latent cooling (unless your garage has a moisture source that drives the wet bulb temp up). Think of it like the interior of a car with the windows up. Your interior can reach 120 - 130 F. Your wet bulb temperature may be 90 - 100 F. When you turn the car AC on you will see very little if any condensation initially. As you sensible temp drops (i.e. as you approach wet bulb temperature) you will start production of condensate.

 

[theoldwizard1]

Shade the condensing unit? Sure.

Cover it? No, it needs as much airflow as possible, and you want to avoid it recirculating air it just expelled back into the inlet side.

Biggest thing is to make sure you take into consideration the de-rate you get with very high outside air temps. The mini-split manufacturers typically give you data with a ~95 degree outside temp. Going up to 110, 115, 120... you're losing a significant amount of that rated capacity.

Excellent advice for folks in extremely hot climates !

 

[marsh1]

Thanks for the feedback. Went with the 30,000BTU heat pump system. Should be up to the task. It is being installed today.

 

[ghnl]

...the manual says the indoor operating range is 64-90...

I would assume that is the set range of the thermostat - what temps you can set for desired indoor temps. Not the operating range for outside temps.

 

[marsh1]

Install went well except the company did not order a line cover. That will be the first project in my air conditioned garage.

It was 98 outside and much hotter in the garage when I turned it on. When out to eat and by the time I got back it was 74.

 

[madamchak]

That looks like an excellent install!