Hello,

We have an old Ruud central air conditioning system from
around the early 80's. The few past years we have noticed that the
system is constantly running and taking longer than it should to cool
the house. So thinking that it was low on refrigerant, we had someone
check the system 2 years ago and they said that it had enough
pressure. So this year I took a temp probe that I use to diagnose air
vents in a car and placed it inside one of our vents. It is reading
about 60 degrees. Now I know on a car that 60F degrees is high and it
should be reading between 40F-50F degrees. Does the system appear that
it may be low on refrigerant and should I get someone else to check
the system?

Thanks,
Nick

wrote in message
So this year I took a temp probe that I use to diagnose air
vents in a car and placed it inside one of our vents. It is reading
about 60 degrees.

What is the temperature going in? If it is 65, it is not cooling enough, If
it is 85, it is doing a good job.

wrote:
Hello,

We have an old Ruud central air conditioning system from
around the early 80's. The few past years we have noticed that the
system is constantly running and taking longer than it should to cool
the house. So thinking that it was low on refrigerant, we had someone
check the system 2 years ago and they said that it had enough
pressure. So this year I took a temp probe that I use to diagnose air
vents in a car and placed it inside one of our vents. It is reading
about 60 degrees. Now I know on a car that 60F degrees is high and it
should be reading between 40F-50F degrees. Does the system appear that
it may be low on refrigerant and should I get someone else to check
the system?

I think the standard is a 20-degree drop. If ambient air is 80, then cooled
to 60 is good.

During the intervening years, your insulation may have settled, or some
other problem involving leakage. Sounds like the A/C is doing the best it
can and the problem might be elsewhere.

Nick, the issues are much more complex than measuring delivery
temperature. I don't know where you get your car information,
either. If an air conditioner can drop the temperature 20
degrees, it is doing about all it can. Get two thermometers -
measure the temperature going in the return air grill and the
temperature coming out of the closest supply grill. If the
difference is 15 to 20 degrees, the unit is working. If the Freon
line outside is sweating, it is a good indication that the gas is
close to right. If it is not sweating, you have a problem. If it
has a sight glass installed and you see bubbles going by, you have
a problem. The air that the fan is blowing out the top of the
condenser should be notably warm to hot. The condensate line
should be delivering a steady stream of water If you live in a
humid climate, it will be quite a heavy stream.

Things to check:
1. Clean the condenser, this involves removing the top of shroud,
using coil cleaner, rinsing from the inside to the outside. Just
washing it off with water is not enough, but it would sure help.

2. Check the filter on the inside. Change the filter anyway.

3. The most likely suspect is leaking duct work or fallen away
insulation on the duct work.

This is all an oversimplification, but should give you enough
advice to understand what a HVAC tech is telling you.

--
______________________________
Keep the whole world singing . . . .
DanG (remove the sevens)




wrote in message
...
Hello,

We have an old Ruud central air conditioning system from
around the early 80's. The few past years we have noticed that
the
system is constantly running and taking longer than it should to
cool
the house. So thinking that it was low on refrigerant, we had
someone
check the system 2 years ago and they said that it had enough
pressure. So this year I took a temp probe that I use to
diagnose air
vents in a car and placed it inside one of our vents. It is
reading
about 60 degrees. Now I know on a car that 60F degrees is high
and it
should be reading between 40F-50F degrees. Does the system
appear that
it may be low on refrigerant and should I get someone else to
check
the system?

Thanks,
Nick

DanG wrote:

Nick, the issues are much more complex than measuring delivery
temperature. I don't know where you get your car information,
either. If an air conditioner can drop the temperature 20
degrees, it is doing about all it can. Get two thermometers -
measure the temperature going in the return air grill and the
temperature coming out of the closest supply grill. If the
difference is 15 to 20 degrees, the unit is working. If the Freon
line outside is sweating, it is a good indication that the gas is
close to right. If it is not sweating, you have a problem. If it
has a sight glass installed and you see bubbles going by, you have
a problem. The air that the fan is blowing out the top of the
condenser should be notably warm to hot. The condensate line
should be delivering a steady stream of water If you live in a
humid climate, it will be quite a heavy stream.

Things to check:
1. Clean the condenser, this involves removing the top of shroud,
using coil cleaner, rinsing from the inside to the outside. Just
washing it off with water is not enough, but it would sure help.

2. Check the filter on the inside. Change the filter anyway.

3. The most likely suspect is leaking duct work or fallen away
insulation on the duct work.

This is all an oversimplification, but should give you enough
advice to understand what a HVAC tech is telling you.

Hmmm,
Evaporator coil needs cleaning as well.

On Jun 7, 6:13*pm, Tony Hwang wrote:
DanG wrote:
Nick, the issues are much more complex than measuring delivery
temperature. *I don't know where you get your car information,
either. *If an air conditioner can drop the temperature 20
degrees, it is doing about all it can. *Get two thermometers -
measure the temperature going in the return air grill and the
temperature coming out of the closest supply grill. *If the
difference is 15 to 20 degrees, the unit is working. *If the Freon
line outside is sweating, it is a good indication that the gas is
close to right. *If it is not sweating, you have a problem. *If it
has a sight glass installed and you see bubbles going by, you have
a problem. *The air that the fan is blowing out the top of the
condenser should be notably warm to hot. *The condensate line
should be delivering a steady stream of water *If you live in a
humid climate, it will be quite a heavy stream.

Things to check:
1. *Clean the condenser, this involves removing the top of shroud,
using coil cleaner, rinsing from the inside to the outside. *Just
washing it off with water is not enough, but it would sure help.

2. *Check the filter on the inside. *Change the filter anyway.

3. *The most likely suspect is leaking duct work or fallen away
insulation on the duct work.

This is all an oversimplification, but should give you enough
advice to understand what a HVAC tech is telling you.

Hmmm,
Evaporator coil needs cleaning as well.- Hide quoted text -

- Show quoted text -

Maybe the air velocity is low due to a slipping v-belt on the blower
if it is a belt-drive blower.

On Jun 7, 8:49�pm, "hr(bob) "
wrote:
On Jun 7, 6:13�pm, Tony Hwang wrote:





DanG wrote:
Nick, the issues are much more complex than measuring delivery
temperature. �I don't know where you get your car information,
either. �If an air conditioner can drop the temperature 20
degrees, it is doing about all it can. �Get two thermometers -
measure the temperature going in the return air grill and the
temperature coming out of the closest supply grill. �If the
difference is 15 to 20 degrees, the unit is working. �If the Freon
line outside is sweating, it is a good indication that the gas is
close to right. �If it is not sweating, you have a problem. �If it
has a sight glass installed and you see bubbles going by, you have
a problem. �The air that the fan is blowing out the top of the
condenser should be notably warm to hot. �The condensate line
should be delivering a steady stream of water �If you live in a
humid climate, it will be quite a heavy stream.

Things to check:
1. �Clean the condenser, this involves removing the top of shroud,
using coil cleaner, rinsing from the inside to the outside. �Just
washing it off with water is not enough, but it would sure help.

2. �Check the filter on the inside. �Change the filter anyway.

3. �The most likely suspect is leaking duct work or fallen away
insulation on the duct work.

This is all an oversimplification, but should give you enough
advice to understand what a HVAC tech is telling you.

Hmmm,
Evaporator coil needs cleaning as well.- Hide quoted text -

- Show quoted text -

Maybe the air velocity is low due to a slipping v-belt on the blower
if it is a belt-drive blower.- Hide quoted text -

- Show quoted text -

Your old unit is likely to be a SEER of 8 or less.

new unit could be 13, nearly twce as efficent.

energy prices keep going up, might be time for a new unit...

might cut electrc bill by half

wrote in news:vmnl445t8qj839invl2fpvj04s3tgqlh3i@
4ax.com:

Hello,

We have an old Ruud central air conditioning system from
around the early 80's. The few past years we have noticed that the
system is constantly running and taking longer than it should to cool
the house. So thinking that it was low on refrigerant, we had someone
check the system 2 years ago and they said that it had enough
pressure. So this year I took a temp probe that I use to diagnose air
vents in a car and placed it inside one of our vents. It is reading
about 60 degrees. Now I know on a car that 60F degrees is high and it
should be reading between 40F-50F degrees. Does the system appear that
it may be low on refrigerant and should I get someone else to check
the system?

Thanks,
Nick

First, I'm not an AC wiz, tech, whatever. Just my experience with several
AC systems in houses I've restored in the past few years and conversation
with an 25yr AC company owner.

As said, the temp differential is what you look for - the difference in
the air temp entering the return vs the temp coming out of a vent. Also
as said, there are many factors. Shortest run vent will likely have the
coolest air coming out, especially if ductwork is in attic.

Brand new system, 25 degrees is excellent.

Existing system let's say less than 10 yrs old system in good shape, 20
degree differential is excellent.

Older system maybe 15 yrs old, 15/16 degrees is good. Unless it needs
cleaning, filters, etc. not worth spending lots of $ to try to get it any
higher.

Other factors - ductwork in an attic vs crawlspace vs indoor main trunk.
Temps of any system will vary in the same system depending on
surroundings. For instanceworst case where the ductwork is in attic and
the unit is sitting in the afternoon sun on a hot day, you can see quite
a difference in the differential in the morning vs the afternoon. Had
this one myself with a heat pump. 20/21 degree differential in the
morning/late evening vs 11-12 degrees differential at 4pm on a 100 degree
day. Coil in superheated attic, ductwork in attic, unit sitting in sun on
100 degree day.

Refrigerant is not the only possible cause. "DanG"'s reply gave you some
good tips. Since you had an AC guy come out, assume he checked those
things? Crudded up condenser has a big effect and an older system has a
much higher probability of that. Less common but possible is a leak in
the return in the attic or return side of the attic unit and now it's
mixing 130 degree air with 78 degree air and trying to cool it.


Just my unofficial .02.

Red Green, Professional....wana-be.
PhD, School of Hard Knocks

Ruud's are notorious (with it's louvered sheetmetal cover) for clogged
coils. and somewhat of a pain to open up. I opened mine up after several
years (we have a cottonwood) and there was a blanket of fuzz an inch and a
half thick. worked much better with that cleaned off.

s


wrote in message
...
Hello,

We have an old Ruud central air conditioning system from
around the early 80's. The few past years we have noticed that the
system is constantly running and taking longer than it should to cool
the house. So thinking that it was low on refrigerant, we had someone
check the system 2 years ago and they said that it had enough
pressure. So this year I took a temp probe that I use to diagnose air
vents in a car and placed it inside one of our vents. It is reading
about 60 degrees. Now I know on a car that 60F degrees is high and it
should be reading between 40F-50F degrees. Does the system appear that
it may be low on refrigerant and should I get someone else to check
the system?

Thanks,
Nick

wrote:

snip

Your old unit is likely to be a SEER of 8 or less.

new unit could be 13, nearly twce as efficent.

energy prices keep going up, might be time for a new unit...

might cut electrc bill by half

Even here in Texas, if the current unit is functioning properly,
it is unlikely that a new unit can be justified on the basis of
electricity savings.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

On Jun 7, 2:23*pm, wrote:
Hello,

* * * * We have an old Ruud central air conditioning system from
around the early 80's. The few past years we have noticed that the
system is constantly running and taking longer than it should to cool
the house. So thinking that it was low on refrigerant, we had someone
check the system 2 years ago and they said that it had enough
pressure. So this year I took a temp probe that I use to diagnose air
vents in a car and placed it inside one of our vents. It is reading
about 60 degrees. Now I know on a car that 60F degrees is high and it
should be reading between 40F-50F degrees. Does the system appear that
it may be low on refrigerant and should I get someone else to check
the system?

Thanks,
Nick

The condensor coil and fan, coil in furnace, blower, need yearly
cleaning and a checkup, it just logical isnt it.

In article , (CJT)
says...
wrote:

snip

Your old unit is likely to be a SEER of 8 or less.

new unit could be 13, nearly twce as efficent.

energy prices keep going up, might be time for a new unit...

might cut electrc bill by half

Even here in Texas, if the current unit is functioning properly,
it is unlikely that a new unit can be justified on the basis of
electricity savings.

It would be wiser to spend the money on additional insulation, upgraded
windows and doors, insulating drapes or blinds, etc. That would give
substantial savings in heating bills as well as cooling. Depending on
the upgrade, insulation improvements can pay back in less than a decade.
I completed my home energy upgrades 4 years ago, and pay 1/3 as much in
utility bills as I did in 2003, even with intervening rate increases.
The house is also much more comfortable to live in.

--
For email, replace firstnamelastinitial
with my first name and last initial.

Larry Caldwell wrote:

In article , (CJT)
says...

wrote:

snip

Your old unit is likely to be a SEER of 8 or less.

new unit could be 13, nearly twce as efficent.

energy prices keep going up, might be time for a new unit...

might cut electrc bill by half

Even here in Texas, if the current unit is functioning properly,
it is unlikely that a new unit can be justified on the basis of
electricity savings.


It would be wiser to spend the money on additional insulation, upgraded
windows and doors, insulating drapes or blinds, etc. That would give
substantial savings in heating bills as well as cooling. Depending on
the upgrade, insulation improvements can pay back in less than a decade.
I completed my home energy upgrades 4 years ago, and pay 1/3 as much in
utility bills as I did in 2003, even with intervening rate increases.
The house is also much more comfortable to live in.

Wow! That's really good. We've managed to cut our consumption by
almost half, but you've got us beat. On the other hand, we didn't
spend much money -- mostly just sealing ductwork, replacing
incandescents with CFL's, and installing (and using) a programmable
thermostat.

--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form .

Thanks for all of the responses. I have measured the temp on the
intake by the attic door and it is reading at 75 degrees. The temp
coming out of the top floor closest to the unit is 62 degrees.

I replace my filters once every month. I'm going to be ordering the
polyester filters that have a better merv rating than the fiberglass
ones I have been using.

I don't know when the condenser coils were last cleaned so I'm going
to be looking there. If anyone has any sites that are good at showing
step by step on how to clean them, I would appreciate it.

Thanks again,
Nick

In article , (CJT)
says...

Wow! That's really good. We've managed to cut our consumption by
almost half, but you've got us beat. On the other hand, we didn't
spend much money -- mostly just sealing ductwork, replacing
incandescents with CFL's, and installing (and using) a programmable
thermostat.

It's all relative. This house was built in 1971, and had never been
upgraded. I installed a heat pump in 1995 (the old furnace was forced
air electric), blew in attic insulation in 1996, put in U .36 windows in
about 2001, then in 2004 we remodelled, including subfloor insulation,
more attic insulation, attic fan, insulated entry and patio doors,
insulated all the water lines, and installed energy star appliances.
While the walls were open, I ran around and foamed all the plate and
plumbing penetrations with foam caulk. We also installed a generator
transfer switch. We are the last house on the power line, and have a
history of power outages lasting several days.

My wife found these nifty insulating blinds that are kind of like a
honeycomb an inch thick that fit inside the window trim like a mini
blind. They are translucent, so they let light in, and are white, so
they reflect heat. They are mostly air, so when you raise them up they
only take up about 2 inches of space at the top of the window.
Combined with the efficient low-E glass, they button things up nicely.
We replaced the old aluminum slider patio door with a Pella french door
that has the mini blinds in between the double glazing panes. I also
added an open porch roof to the west side of the house that shades that
wall on hot afternoons.

The next step is solar hot water. We don't have a great solar site, but
we do have wood heat. I figure between coils on the roof and coils
behind the wood stove, we could produce 80% of our hot water for free.
Someday I want to add another layer of insulation on the walls and
install cement board siding, which would turn the outside walls into a
thermal break system.

Down the road I would like to install a high pressure gravity feed water
system. We already have a low pressure system with about 10 feet of
head. A power outage means we lose most of our water pressure, but not
all of it. You can still flush a toilet or fill a bathtub. We have
decorated the house with brass candle sconces and wall mounted oil
lamps. When the power goes out, we can light the house, do dishes (by
hand) and cook on the wood stove. The insulation upgrade means only
about a 15 degree temperature drop from one end of the house to the
other in freezing weather.

Energy upgrades don't all have to happen at once, but they are a gift
that just keeps on giving.

--
For email, replace firstnamelastinitial
with my first name and last initial.