Discussion:
Condensor Fan Flow Direction
(too old to reply)
Frank Boettcher
2003-11-06 17:54:10 UTC
Permalink
I'm replacing a condensor fan, fan motor and capacitor on a five ton
packaged (not split) heat pump. The unit has a 1/2 hp, dual
rotation, single speed, 1075 rpm motor with a 22" dia fan with 35
degree pitch angle. Book says this is a proper fan/motor matchup.

The motor rotation and fan installation is set up to draw air into
the top grill across the motor which hangs from the grill in about an
eight inch deep fan housing, with the fan blade below the motor and
then across the coils from the inside out. Coils are set up on two
adjacent sides of the condensor coil box.

A friend told me he thought you always drew in from the bottom/sides
and out the top. I wouldn't necessarily question what I currently
have except that this fan motor has been replaced once, but by an HVAC
service company. I'm assumming they knew what they were doing and did
the replacement per factory specs with the rotation and flow in the
proper direction.

I have an old installation manual but it does not comment on anything
that was set at the factory only hook up wiring. The wiring diagram
is to faded to read.

Comments from anyone who has experience with HVAC installations
please. Is the flow as currently set correct? Is the flow direction
optional? It seems to me you would design with a slight back pressure
so that you could make sure you were contacting all the coil surfaces
and the way to do that, I would think, is to flow as it is currently
installed as described above.

Thanks for any comments.
Steve
2003-11-06 16:21:17 UTC
Permalink
I'm no HVAC expert, but have a heat pump and the fan draws the air from the
sides, through the coils and out the top..

I think having the air going in the top and out through the coils would
cause dirt and trash to accumulate in the inexcessable inside of the coils,
while in the other direction, this accumulation would be on the outside
where it could be cleaned off. (I hose mine off each season)..

My experience and opinion. FWIW.

Steve
mark Ransley
2003-11-06 16:23:16 UTC
Permalink
Im no pro , but Ive always seen them blow up.
jim
2003-11-06 19:57:11 UTC
Permalink
Post by Frank Boettcher
I'm replacing a condensor fan, fan motor and capacitor on a five ton
packaged (not split) heat pump. The unit has a 1/2 hp, dual
rotation, single speed, 1075 rpm motor with a 22" dia fan with 35
degree pitch angle. Book says this is a proper fan/motor matchup.
The motor rotation and fan installation is set up to draw air into
the top grill across the motor which hangs from the grill in about an
eight inch deep fan housing, with the fan blade below the motor and
then across the coils from the inside out. Coils are set up on two
adjacent sides of the condensor coil box.
A friend told me he thought you always drew in from the bottom/sides
and out the top. I wouldn't necessarily question what I currently
have except that this fan motor has been replaced once, but by an HVAC
service company. I'm assumming they knew what they were doing and did
the replacement per factory specs with the rotation and flow in the
proper direction.
I have an old installation manual but it does not comment on anything
that was set at the factory only hook up wiring. The wiring diagram
is to faded to read.
Comments from anyone who has experience with HVAC installations
please. Is the flow as currently set correct? Is the flow direction
optional? It seems to me you would design with a slight back pressure
so that you could make sure you were contacting all the coil surfaces
and the way to do that, I would think, is to flow as it is currently
installed as described above.
Thanks for any comments.
just because someone in the H/ac business did it does not mean it was
done correctly... it should have, but they also hire flakes and let them
go by the dozens and hire more.. its all money.. who can bring in the
most money and how fast they can do it.
jriegle
2003-11-06 23:58:39 UTC
Permalink
I'd say your friend is correct. The fan creates a slight vacuum behind it.
Air will be nearly evenly drawn across the coil surface area for maximum
efficiency. If the fan blows into the unit, the direction and velocity of
the air will favor one part of the coil better than the other parts = lower
efficiency. Also, the heated air will rise and can be drawn back in. It can
also be directed back to the unit by nearby objects. The heated air expelled
through the top will not likely re-enter the unit. Also, in the winter, the
cold air expelled from the top has a less chance of re-entering the unit
because of it's higher velocity pushing it away.
John
Post by Frank Boettcher
I'm replacing a condensor fan, fan motor and capacitor on a five ton
packaged (not split) heat pump. The unit has a 1/2 hp, dual
rotation, single speed, 1075 rpm motor with a 22" dia fan with 35
degree pitch angle. Book says this is a proper fan/motor matchup.
The motor rotation and fan installation is set up to draw air into
the top grill across the motor which hangs from the grill in about an
eight inch deep fan housing, with the fan blade below the motor and
then across the coils from the inside out. Coils are set up on two
adjacent sides of the condensor coil box.
A friend told me he thought you always drew in from the bottom/sides
and out the top. I wouldn't necessarily question what I currently
have except that this fan motor has been replaced once, but by an HVAC
service company. I'm assumming they knew what they were doing and did
the replacement per factory specs with the rotation and flow in the
proper direction.
I have an old installation manual but it does not comment on anything
that was set at the factory only hook up wiring. The wiring diagram
is to faded to read.
Comments from anyone who has experience with HVAC installations
please. Is the flow as currently set correct? Is the flow direction
optional? It seems to me you would design with a slight back pressure
so that you could make sure you were contacting all the coil surfaces
and the way to do that, I would think, is to flow as it is currently
installed as described above.
Thanks for any comments.
CBHvac
2003-11-07 01:56:37 UTC
Permalink
Post by Frank Boettcher
I'm replacing a condensor fan, fan motor and capacitor on a five ton
packaged (not split) heat pump. The unit has a 1/2 hp, dual
rotation, single speed, 1075 rpm motor with a 22" dia fan with 35
degree pitch angle. Book says this is a proper fan/motor matchup.
Dual rotation?
You mean reversable right?
Post by Frank Boettcher
The motor rotation and fan installation is set up to draw air into
the top grill across the motor which hangs from the grill in about an
eight inch deep fan housing, with the fan blade below the motor and
then across the coils from the inside out. Coils are set up on two
adjacent sides of the condensor coil box.
A friend told me he thought you always drew in from the bottom/sides
and out the top. I wouldn't necessarily question what I currently
have except that this fan motor has been replaced once, but by an HVAC
service company. I'm assumming they knew what they were doing and did
the replacement per factory specs with the rotation and flow in the
proper direction.
Not always...old York Doghouses blew in and out..the coils..
Post by Frank Boettcher
I have an old installation manual but it does not comment on anything
that was set at the factory only hook up wiring. The wiring diagram
is to faded to read.
Comments from anyone who has experience with HVAC installations
please. Is the flow as currently set correct? Is the flow direction
optional? It seems to me you would design with a slight back pressure
so that you could make sure you were contacting all the coil surfaces
and the way to do that, I would think, is to flow as it is currently
installed as described above.
Thanks for any comments.
Well...95% of the units out there blow up through the coils..but since you
have not even posted close to enough information, no one knows..
I will state that if you dont get the fan back on at the right location,
your compressor will love you for it...not.
Stormin Mormonn
2003-11-07 12:49:20 UTC
Permalink
If you draw in the sides and out the top, you're cooperating with the
natural flow "heat rises".

You also make it easier to see if the coils are dirty -- cause the dust will
be on the outside.

Every condensing unit I've seen, the air sucks in the sides and blows out
the top.

--

Christopher a. Young
Learn more about Jesus
www.lds.org
www.mormons.org


"Frank Boettcher" <***@ebicom.net> wrote in message news:boWqPytF1NkSwO6XMubeEO+***@4ax.com...


I'm replacing a condensor fan, fan motor and capacitor on a five ton
packaged (not split) heat pump. The unit has a 1/2 hp, dual
rotation, single speed, 1075 rpm motor with a 22" dia fan with 35
degree pitch angle. Book says this is a proper fan/motor matchup.

The motor rotation and fan installation is set up to draw air into
the top grill across the motor which hangs from the grill in about an
eight inch deep fan housing, with the fan blade below the motor and
then across the coils from the inside out. Coils are set up on two
adjacent sides of the condensor coil box.

A friend told me he thought you always drew in from the bottom/sides
and out the top. I wouldn't necessarily question what I currently
have except that this fan motor has been replaced once, but by an HVAC
service company. I'm assumming they knew what they were doing and did
the replacement per factory specs with the rotation and flow in the
proper direction.

I have an old installation manual but it does not comment on anything
that was set at the factory only hook up wiring. The wiring diagram
is to faded to read.

Comments from anyone who has experience with HVAC installations
please. Is the flow as currently set correct? Is the flow direction
optional? It seems to me you would design with a slight back pressure
so that you could make sure you were contacting all the coil surfaces
and the way to do that, I would think, is to flow as it is currently
installed as described above.

Thanks for any comments.
Frank Boettcher
2003-11-07 17:39:53 UTC
Permalink
Follow up:

I got a factory spec chart and as it turns out it is specified to draw
in and exhaust up. The service tech who replaced the motor the last
time mounted the blade upside down and left the motor rotation cw.
Just goes to show you even the so called pros make mistakes.

I'm sure it makes a difference, however the heat pump operated like
that for about four years. Hopefully, I will gain some efficiency by
going back the other way.


On Thu, 06 Nov 2003 09:54:10 -0800, Frank Boettcher
Post by Frank Boettcher
I'm replacing a condensor fan, fan motor and capacitor on a five ton
packaged (not split) heat pump. The unit has a 1/2 hp, dual
rotation, single speed, 1075 rpm motor with a 22" dia fan with 35
degree pitch angle. Book says this is a proper fan/motor matchup.
The motor rotation and fan installation is set up to draw air into
the top grill across the motor which hangs from the grill in about an
eight inch deep fan housing, with the fan blade below the motor and
then across the coils from the inside out. Coils are set up on two
adjacent sides of the condensor coil box.
A friend told me he thought you always drew in from the bottom/sides
and out the top. I wouldn't necessarily question what I currently
have except that this fan motor has been replaced once, but by an HVAC
service company. I'm assumming they knew what they were doing and did
the replacement per factory specs with the rotation and flow in the
proper direction.
I have an old installation manual but it does not comment on anything
that was set at the factory only hook up wiring. The wiring diagram
is to faded to read.
Comments from anyone who has experience with HVAC installations
please. Is the flow as currently set correct? Is the flow direction
optional? It seems to me you would design with a slight back pressure
so that you could make sure you were contacting all the coil surfaces
and the way to do that, I would think, is to flow as it is currently
installed as described above.
Thanks for any comments.
CBHvac
2003-11-07 22:11:22 UTC
Permalink
Post by Frank Boettcher
I got a factory spec chart and as it turns out it is specified to draw
in and exhaust up. The service tech who replaced the motor the last
time mounted the blade upside down and left the motor rotation cw.
Just goes to show you even the so called pros make mistakes.
Actually, there are fewer and fewer real pros...most are $20 an hour
flunkies working for the real pros..and thats a shame.
Post by Frank Boettcher
I'm sure it makes a difference, however the heat pump operated like
that for about four years. Hopefully, I will gain some efficiency by
going back the other way.
You will...my question tho is...with the fan set screw the way they are, how
in hell did he get it back on wrong, unless it was on the end of the motor
shaft, and that would have put it far below where it needed to be.
Post by Frank Boettcher
On Thu, 06 Nov 2003 09:54:10 -0800, Frank Boettcher
Post by Frank Boettcher
I'm replacing a condensor fan, fan motor and capacitor on a five ton
packaged (not split) heat pump. The unit has a 1/2 hp, dual
rotation, single speed, 1075 rpm motor with a 22" dia fan with 35
degree pitch angle. Book says this is a proper fan/motor matchup.
The motor rotation and fan installation is set up to draw air into
the top grill across the motor which hangs from the grill in about an
eight inch deep fan housing, with the fan blade below the motor and
then across the coils from the inside out. Coils are set up on two
adjacent sides of the condensor coil box.
A friend told me he thought you always drew in from the bottom/sides
and out the top. I wouldn't necessarily question what I currently
have except that this fan motor has been replaced once, but by an HVAC
service company. I'm assumming they knew what they were doing and did
the replacement per factory specs with the rotation and flow in the
proper direction.
I have an old installation manual but it does not comment on anything
that was set at the factory only hook up wiring. The wiring diagram
is to faded to read.
Comments from anyone who has experience with HVAC installations
please. Is the flow as currently set correct? Is the flow direction
optional? It seems to me you would design with a slight back pressure
so that you could make sure you were contacting all the coil surfaces
and the way to do that, I would think, is to flow as it is currently
installed as described above.
Thanks for any comments.
Continue reading on narkive:
Loading...