It's 80 degrees in my house with 58% humidity. Time for some AC.

Comfort 90 Max (Rheem) with Central Air

2 questions:

1 - With the fan set to "On" and the temp set to 70, I turned on the
AC. Here's what it does:

The blower will run for about 20 minutes (I didn't time it) and then
shut off for about 30 seconds. It does this continually and it's been
doing it for at least a couple of years. I first noticed it last
summer but I can't honestly say whether or not it's been doing it
since the unit was installed 5 years ago.

It only does this when the AC is on, not when the heat is on or when
the blower is set to On just to circulate the air. It's only when I'm
using the AC does the blower take a break.

Is this normal?

2 - I checked the temperature differential between the return trunk
and the plenum just above the AC coils.

77 in the return trunk, 64 in the plenum, except when the blower turns
off (see above). When the blower turns off, the plenum temperature
drops to 59. After the blower come back on (~30 seconds later) the
plenum temperature goes back up to 64.

What do think about that differential?

On Jun 1, 5:20*am, DerbyDad03 wrote:
It's 80 degrees in my house with 58% humidity. *Time for some AC.

Comfort 90 Max (Rheem) with Central Air

2 questions:

1 - With the fan set to "On" and the temp set to 70, I turned on the
AC. Here's what it does:

The blower will run for about 20 minutes (I didn't time it) and then
shut off for about 30 seconds. It does this continually and it's been
doing it for at least a couple of years. I first noticed it last
summer but I can't honestly say whether or not it's been doing it
since the unit was installed 5 years ago.

It only does this when the AC is on, not when the heat is on or when
the blower is set to On just to circulate the air. It's only when I'm
using the AC does the blower take a break.

Is this normal?

2 - I checked the temperature differential between the return trunk
and the plenum just above the AC coils.

77 in the return trunk, 64 in the plenum, except when the blower turns
off (see above). When the blower turns off, the plenum temperature
drops to 59. After the blower come back on (~30 seconds later) the
plenum temperature goes back up to 64.

What do think about that differential?

There is probably an air pressure switch in the ductwork. I would
start by looking at that.

On Jun 1, 12:20*am, DerbyDad03 wrote:
It's 80 degrees in my house with 58% humidity. *Time for some AC.

Comfort 90 Max (Rheem) with Central Air

2 questions:

1 - With the fan set to "On" and the temp set to 70, I turned on the
AC. Here's what it does:

The blower will run for about 20 minutes (I didn't time it) and then
shut off for about 30 seconds. It does this continually and it's been
doing it for at least a couple of years. I first noticed it last
summer but I can't honestly say whether or not it's been doing it
since the unit was installed 5 years ago.

It only does this when the AC is on, not when the heat is on or when
the blower is set to On just to circulate the air. It's only when I'm
using the AC does the blower take a break.

Is this normal?

2 - I checked the temperature differential between the return trunk
and the plenum just above the AC coils.

77 in the return trunk, 64 in the plenum, except when the blower turns
off (see above). When the blower turns off, the plenum temperature
drops to 59. After the blower come back on (~30 seconds later) the
plenum temperature goes back up to 64.

What do think about that differential?

An update:

Now that the house is at 71 degrees, it doesn't seem to be cycling the
blower. I just monitored it for 40 minutes and it hasn't turned off.
That's longer than when the house was at 80.

The temp differential is 69 - 57.

Shouldn't it be higher, like around 15+ degrees?

Removing humidity takes a LOT of power, so the 12 degree
drop may be OK. Not sure from here, why the fan turns off.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"DerbyDad03" wrote in message
...
On Jun 1, 12:20 am, DerbyDad03 wrote:
It's 80 degrees in my house with 58% humidity. Time for
some AC.

Comfort 90 Max (Rheem) with Central Air

2 questions:

1 - With the fan set to "On" and the temp set to 70, I
turned on the
AC. Here's what it does:

The blower will run for about 20 minutes (I didn't time
it) and then
shut off for about 30 seconds. It does this continually
and it's been
doing it for at least a couple of years. I first noticed
it last
summer but I can't honestly say whether or not it's been
doing it
since the unit was installed 5 years ago.

It only does this when the AC is on, not when the heat is
on or when
the blower is set to On just to circulate the air. It's
only when I'm
using the AC does the blower take a break.

Is this normal?

2 - I checked the temperature differential between the
return trunk
and the plenum just above the AC coils.

77 in the return trunk, 64 in the plenum, except when the
blower turns
off (see above). When the blower turns off, the plenum
temperature
drops to 59. After the blower come back on (~30 seconds
later) the
plenum temperature goes back up to 64.

What do think about that differential?

An update:

Now that the house is at 71 degrees, it doesn't seem to be
cycling the
blower. I just monitored it for 40 minutes and it hasn't
turned off.
That's longer than when the house was at 80.

The temp differential is 69 - 57.

Shouldn't it be higher, like around 15+ degrees?

On Jun 1, 12:20*am, DerbyDad03 wrote:
It's 80 degrees in my house with 58% humidity. *Time for some AC.

Comfort 90 Max (Rheem) with Central Air

2 questions:

1 - With the fan set to "On" and the temp set to 70, I turned on the
AC. Here's what it does:

The blower will run for about 20 minutes (I didn't time it) and then
shut off for about 30 seconds. It does this continually and it's been
doing it for at least a couple of years. I first noticed it last
summer but I can't honestly say whether or not it's been doing it
since the unit was installed 5 years ago.

It only does this when the AC is on, not when the heat is on or when
the blower is set to On just to circulate the air. It's only when I'm
using the AC does the blower take a break.

Is this normal?

Every system I've seen, if you set the fan to on
it stays on continually



2 - I checked the temperature differential between the return trunk
and the plenum just above the AC coils.

77 in the return trunk, 64 in the plenum, except when the blower turns
off (see above). When the blower turns off, the plenum temperature
drops to 59. After the blower come back on (~30 seconds later) the
plenum temperature goes back up to 64.

What do think about that differential?

Seems on the low side. Somewhere around 18F is more typical.
But it depends on how much air is moving, ie the air handler size,
the speed it's actually running at, together with the cooling system
capacity.

On Jun 1, 12:20*am, DerbyDad03 wrote:
It's 80 degrees in my house with 58% humidity. *Time for some AC.

Comfort 90 Max (Rheem) with Central Air

2 questions:

1 - With the fan set to "On" and the temp set to 70, I turned on the
AC. Here's what it does:

The blower will run for about 20 minutes (I didn't time it) and then
shut off for about 30 seconds. It does this continually and it's been
doing it for at least a couple of years. I first noticed it last
summer but I can't honestly say whether or not it's been doing it
since the unit was installed 5 years ago.

It only does this when the AC is on, not when the heat is on or when
the blower is set to On just to circulate the air. It's only when I'm
using the AC does the blower take a break.

Is this normal?

2 - I checked the temperature differential between the return trunk
and the plenum just above the AC coils.

77 in the return trunk, 64 in the plenum, except when the blower turns
off (see above). When the blower turns off, the plenum temperature
drops to 59. After the blower come back on (~30 seconds later) the
plenum temperature goes back up to 64.

What do think about that differential?

Does the compressor shutdown as well?

On Jun 1, 8:08*am, jamesgangnc wrote:
On Jun 1, 12:20*am, DerbyDad03 wrote:





It's 80 degrees in my house with 58% humidity. *Time for some AC.

Comfort 90 Max (Rheem) with Central Air

2 questions:

1 - With the fan set to "On" and the temp set to 70, I turned on the
AC. Here's what it does:

The blower will run for about 20 minutes (I didn't time it) and then
shut off for about 30 seconds. It does this continually and it's been
doing it for at least a couple of years. I first noticed it last
summer but I can't honestly say whether or not it's been doing it
since the unit was installed 5 years ago.

It only does this when the AC is on, not when the heat is on or when
the blower is set to On just to circulate the air. It's only when I'm
using the AC does the blower take a break.

Is this normal?

2 - I checked the temperature differential between the return trunk
and the plenum just above the AC coils.

77 in the return trunk, 64 in the plenum, except when the blower turns
off (see above). When the blower turns off, the plenum temperature
drops to 59. After the blower come back on (~30 seconds later) the
plenum temperature goes back up to 64.

What do think about that differential?

Does the compressor shutdown as well?- Hide quoted text -

- Show quoted text -

Don't know...will have to check the next time it happens.

As I mentioned in my update, once the house cooled down, the blower
stopped cycling and stayed on continuously, as least for the 40
minutes or so that I was monitoring it.

Since this was an overnight thing, I didn't have a chance to spend
hours monitoring the system to get more specific details. Maybe this
weekend, if it's hot enough I can get more data.

On Jun 1, 9:52*am, DerbyDad03 wrote:
On Jun 1, 8:08*am, jamesgangnc wrote:





On Jun 1, 12:20*am, DerbyDad03 wrote:

It's 80 degrees in my house with 58% humidity. *Time for some AC.

Comfort 90 Max (Rheem) with Central Air

2 questions:

1 - With the fan set to "On" and the temp set to 70, I turned on the
AC. Here's what it does:

The blower will run for about 20 minutes (I didn't time it) and then
shut off for about 30 seconds. It does this continually and it's been
doing it for at least a couple of years. I first noticed it last
summer but I can't honestly say whether or not it's been doing it
since the unit was installed 5 years ago.

It only does this when the AC is on, not when the heat is on or when
the blower is set to On just to circulate the air. It's only when I'm
using the AC does the blower take a break.

Is this normal?

2 - I checked the temperature differential between the return trunk
and the plenum just above the AC coils.

77 in the return trunk, 64 in the plenum, except when the blower turns
off (see above). When the blower turns off, the plenum temperature
drops to 59. After the blower come back on (~30 seconds later) the
plenum temperature goes back up to 64.

What do think about that differential?

Does the compressor shutdown as well?- Hide quoted text -

- Show quoted text -

Don't know...will have to check the next time it happens.

As I mentioned in my update, once the house cooled down, the blower
stopped cycling and stayed on continuously, as least for the 40
minutes or so that I was monitoring it.

Since this was an overnight thing, I didn't have a chance to spend
hours monitoring the system to get more specific details. Maybe this
weekend, if it's hot enough I can get more data.- Hide quoted text -

- Show quoted text -

You will have to actually monitor the compressor and the blower, to
see if the blower stops whenever the compresor starts under heavy
load, like when it is reallyhot. WHen it is not as hot, the
compressor may not start under as heavy a load and thus somehow not
shut off the blower.