Sizing a mini-split a/c
 

A friend is looking into putting in a mini-split air conditioner. The room
does not have an outside wall. She has calculated that she needs 6000 to
7000 BTU--max. But all single zone units I find are about 9000 BTU. She
very much does not want an oversized unit that leaves the room cold and
clammy.

Some units I find have a dehumidifying mode. Does this mean that when it
reaches the set point temperature it continues to run to remove the
humidity?

Investigating the Sanyo LS093CE (115 volts, no heat mode) it appears that
the unit can either be run as a/c, or run as a dehumidifier. And that there
is also a condensate line that is run from the indoor unit. What would be
better is a unit that above the set point it is a/c and below it is a
dehumidifier. Does such exist?

Don www.donwiss.com (e-mail link at home page bottom).

Sizing a mini-split a/c
 

wrote:
On Thu, 17 Jun 2010 16:40:09 -0400, Don Wiss
wrote:

A friend is looking into putting in a mini-split air conditioner. The room
does not have an outside wall. She has calculated that she needs 6000 to
7000 BTU--max. But all single zone units I find are about 9000 BTU. She
very much does not want an oversized unit that leaves the room cold and
clammy.

Some units I find have a dehumidifying mode. Does this mean that when it
reaches the set point temperature it continues to run to remove the
humidity?

It rusn teh fan at a lower speed, to increase the humidity
ratio it removes.

Dammit, Paul, I told you not to buy the cheap booze.....;-p

Investigating the Sanyo LS093CE (115 volts, no heat mode) it appears that
the unit can either be run as a/c, or run as a dehumidifier. And that there
is also a condensate line that is run from the indoor unit. What would be
better is a unit that above the set point it is a/c and below it is a
dehumidifier. Does such exist?

Don' worry about it. Get one with 'dehumidify mode' as above.

Don www.donwiss.com (e-mail link at home page bottom).

Sizing a mini-split a/c
 

"Don Wiss" wrote in message
...
A friend is looking into putting in a mini-split air conditioner. The room
does not have an outside wall. She has calculated that she needs 6000 to
7000 BTU--max. But all single zone units I find are about 9000 BTU. She
very much does not want an oversized unit that leaves the room cold and
clammy.

Some units I find have a dehumidifying mode. Does this mean that when it
reaches the set point temperature it continues to run to remove the
humidity?

Investigating the Sanyo LS093CE (115 volts, no heat mode) it appears that
the unit can either be run as a/c, or run as a dehumidifier. And that
there
is also a condensate line that is run from the indoor unit. What would be
better is a unit that above the set point it is a/c and below it is a
dehumidifier. Does such exist?

Don www.donwiss.com (e-mail link at home page bottom).

Yes it does exist.... and uses Variable Frequency Inverter technology. Go
here;

http://www.fujitsugeneral.com/wallmountediaq9-12.htm

Sizing a mini-split a/c
 

In article ,
says...
A friend is looking into putting in a mini-split air conditioner. The room
does not have an outside wall. She has calculated that she needs 6000 to
7000 BTU--max. But all single zone units I find are about 9000 BTU. She
very much does not want an oversized unit that leaves the room cold and
clammy.

Some units I find have a dehumidifying mode. Does this mean that when it
reaches the set point temperature it continues to run to remove the
humidity?


It does *not* mean that. Unfortunately, the mini splits do not have a very
sophisticated control scheme. All the dehumidify mode means is that the unit
cycles on and off on a fixed timer. It does not control temperature at all in
this mode. Mine runs for something like 7 minutes on, then 3 minutes off.

We tend to have many days with high humidity but not real high outside
temperatures, and the dehumidify mode works fairly well. But if it cools off
in the evening, it can make the room quite cold.

--
DT

Sizing a mini-split a/c
 

snipped
It does *not* mean that. Unfortunately, the mini splits do not have a very
sophisticated control scheme. All the dehumidify mode means is that the
unit
cycles on and off on a fixed timer. It does not control temperature at all
in
this mode. Mine runs for something like 7 minutes on, then 3 minutes off.


thats not correct a correct statement, with the new Fujitsu mini-split heat
pumps.... they use Variable frequency inverter drives and literally vary
their motor and compressor speeds for demand dehumidification without
turning the place into a walk in freeze box. The RLQ and RLS series
literally vary their output from 40% to 115% of their rated capacity
depending on demand.

Sizing a mini-split a/c
 

wrote in message
...
On Sat, 19 Jun 2010 11:55:37 -0500, "Steve"
wrote:


snipped
It does *not* mean that. Unfortunately, the mini splits do not have a
very
sophisticated control scheme. All the dehumidify mode means is that the
unit
cycles on and off on a fixed timer. It does not control temperature at
all
in
this mode. Mine runs for something like 7 minutes on, then 3 minutes
off.


thats not correct a correct statement, with the new Fujitsu mini-split
heat
pumps.... they use Variable frequency inverter drives and literally vary
their motor and compressor speeds for demand dehumidification without
turning the place into a walk in freeze box. The RLQ and RLS series
literally vary their output from 40% to 115% of their rated capacity
depending on demand.


Dat be some nifty ****.

I installed the 15RLQ system yesterday for a customer that is an EE... he is
like a kid with a new toy :-)

Got a 9RLS that I will be installing next week for another customer. (I
installed a 15RLQ in this guys shop last winter and he loves it. ) He closed
in his back porch/patio and wants another one. :-)

Sizing a mini-split a/c
 

In article ,
says...
snipped
It does *not* mean that. Unfortunately, the mini splits do not have a very
sophisticated control scheme. All the dehumidify mode means is that the
unit
cycles on and off on a fixed timer. It does not control temperature at all
in
this mode. Mine runs for something like 7 minutes on, then 3 minutes off.


thats not correct a correct statement, with the new Fujitsu mini-split heat
pumps.... they use Variable frequency inverter drives and literally vary
their motor and compressor speeds for demand dehumidification without
turning the place into a walk in freeze box. The RLQ and RLS series
literally vary their output from 40% to 115% of their rated capacity
depending on demand.


Nice. Sounds expensive, but nice! I have had my mini split for 4 years and
when I researched them back then I was dismayed at how unsophisticated they
were. One thing that might improve them is a true remote temperature sensor
(not just a remote control). I added a remote sensor and controller with
adjustable span to a window unit and it transformed the way it controlled the
room temperature and lowered the humidity.

--
DT

Sizing a mini-split a/c
 

"DT" wrote in message
...
In article ,
says...
snipped
It does *not* mean that. Unfortunately, the mini splits do not have a
very
sophisticated control scheme. All the dehumidify mode means is that the
unit
cycles on and off on a fixed timer. It does not control temperature at
all
in
this mode. Mine runs for something like 7 minutes on, then 3 minutes
off.


thats not correct a correct statement, with the new Fujitsu mini-split
heat
pumps.... they use Variable frequency inverter drives and literally vary
their motor and compressor speeds for demand dehumidification without
turning the place into a walk in freeze box. The RLQ and RLS series
literally vary their output from 40% to 115% of their rated capacity
depending on demand.


Nice. Sounds expensive, but nice! I have had my mini split for 4 years and
when I researched them back then I was dismayed at how unsophisticated
they
were. One thing that might improve them is a true remote temperature
sensor
(not just a remote control). I added a remote sensor and controller with
adjustable span to a window unit and it transformed the way it controlled
the
room temperature and lowered the humidity.

--
DT

Expensive is relative..... According to ARI, $235/year to heat and cool for
the 15RLQ is cheap to operate by any standard.... the ones I have put in
were $2,700 plus tax installed.
http://www.fujitsugeneral.com/wallmo...pecs.htm#specs

Sizing a mini-split a/c
 

On Sat, 19 Jun 2010 11:55:37 -0500, Steve wrote:

thats not correct a correct statement, with the new Fujitsu mini-split heat
pumps.... they use Variable frequency inverter drives and literally vary
their motor and compressor speeds for demand dehumidification without
turning the place into a walk in freeze box. The RLQ and RLS series
literally vary their output from 40% to 115% of their rated capacity
depending on demand.

Hi Steve,

You've sold me. I have wanted a variable speed a/c for more than 20 years.
When I put the Carrier packaged unit on the roof six years ago I wanted it.
But it wasn't an option, so I settled for undersizing it a little. Then
when I replaced my downstairs regular split unit two years ago it was
available! This being the Carrier Infinity. It is nice to find out that
this feature is finally making it to the mini-splits.

My friend (we're in Brooklyn) just now has to get a couple proposals and
get the coop to approve the hole through the outside wall. There is already
electricity outside on the balcony. I would think a 3/4"-1" hole would do.

Thanks, Don www.donwiss.com (e-mail link at home page bottom).

Sizing a mini-split a/c
 

On Sat, 19 Jun 2010, wrote:

Make sure it's the RIGHT electricity. It's likely not. It's
likely 120V, you likely need 230V. However, the wire MIGHT be able to
be re-purposed if needed ( if it's an independent circuit now ). Have
your ( licensed insured ) contractor tell you.

The hole he's gonna have to make might be used to good avail also to
bring some other 120v circuit outside, if he re-purposes the existing
wire to 230 V.

I know it is now 120 volt on the balcony.

Hmm... I was looking at the 9CQ he
http://www.fujitsugeneral.com/wallmo...pecs.htm#specs

I see 115 volt. But that isn't the unit that gets the 30% tax credit. That
is the 9RL he
http://www.fujitsugeneral.com/wallmo...pecs.htm#specs

Which is 230 volt. And it appears that the supply voltage for the inside
unit is fed from the outside unit. And not just a low voltage wire. So a
bigger hole. Walls in her apartment building are poured concrete or
concrete block. Running 230 out there would be a major problem.

Don www.donwiss.com (e-mail link at home page bottom).

Sizing a mini-split a/c
 

On Sat, 19 Jun 2010 22:51:01 -0400, wrote:

On Sat, 19 Jun 2010 20:22:24 -0400, Don Wiss wrote:

I know it is now 120 volt on the balcony.

Hmm... I was looking at the 9CQ he
http://www.fujitsugeneral.com/wallmo...pecs.htm#specs

I see 115 volt. But that isn't the unit that gets the 30% tax credit. That
is the 9RL he
http://www.fujitsugeneral.com/wallmo...pecs.htm#specs

Which is 230 volt. And it appears that the supply voltage for the inside
unit is fed from the outside unit. And not just a low voltage wire. So a
bigger hole. Walls in her apartment building are poured concrete or
concrete block. Running 230 out there would be a major problem.

Can you get 230 to the inside unit, maybe through the attic?
When they installed mine, the raceway we took to the outside unit also
brought the wires back to the inside unit. I fed it from a J box in
the middle but it could have been fed from the inside unit just as
easy.

Nope. This is an apartment building. There are apartments all around her.

A little background. When the building was build in about the 1960s they
put in through the wall air conditioners. They sized them generously. The
apartment was originally a one bedroom. The three through the walls were in
the bedroom, in the kitchen, and in the living room. Somewhere along the
way the living room was chopped into a small bedroom with the windows, and
a large windowless living room. That room can't now be cooled. The other
rooms are cold and clammy if the a/c is used. I can't get the sizes out of
her for the through the wall units. It was hard enough to get her to
calculate the BTUs needed for the living room. But we are assuming that the
size of those units is pretty fixed by the sleeve size.

Don www.donwiss.com (e-mail link at home page bottom).

Sizing a mini-split a/c
 

On 6/19/2010 11:44 PM, Don Wiss wrote:
On Sat, 19 Jun 2010 22:51:01 -0400, wrote:

On Sat, 19 Jun 2010 20:22:24 -0400, Don Wiss wrote:

I know it is now 120 volt on the balcony.

Hmm... I was looking at the 9CQ he
http://www.fujitsugeneral.com/wallmo...pecs.htm#specs

I see 115 volt. But that isn't the unit that gets the 30% tax credit. That
is the 9RL he
http://www.fujitsugeneral.com/wallmo...pecs.htm#specs

Which is 230 volt. And it appears that the supply voltage for the inside
unit is fed from the outside unit. And not just a low voltage wire. So a
bigger hole. Walls in her apartment building are poured concrete or
concrete block. Running 230 out there would be a major problem.

Can you get 230 to the inside unit, maybe through the attic?
When they installed mine, the raceway we took to the outside unit also
brought the wires back to the inside unit. I fed it from a J box in
the middle but it could have been fed from the inside unit just as
easy.

Nope. This is an apartment building. There are apartments all around her.

A little background. When the building was build in about the 1960s they
put in through the wall air conditioners. They sized them generously. The
apartment was originally a one bedroom. The three through the walls were in
the bedroom, in the kitchen, and in the living room. Somewhere along the
way the living room was chopped into a small bedroom with the windows, and
a large windowless living room. That room can't now be cooled. The other
rooms are cold and clammy if the a/c is used. I can't get the sizes out of
her for the through the wall units. It was hard enough to get her to
calculate the BTUs needed for the living room. But we are assuming that the
size of those units is pretty fixed by the sleeve size.

Donwww.donwiss.com (e-mail link at home page bottom).

Did you ever consider installing through the wall room to room
ventilation fans? I've installed them in convenience stores
where the clerk is inside the bullet resistant enclosure and I
know the fans were designed for homes that need air moved into
other rooms.

TDD