How your 3-ton A/C could only be operating at One Ton (Awe, you're kidding;
NO I'm NOT!)
Only two of many diverse factors that can cause very low Btu/hr evaporator
heat-load absorption and transfer scenarios.

Every refrigerant has a "vaporization" heat absorption factor per pound.
This heat-absorption effect is rated in Btu per pound of refrigerant.
(Btu/lb); if the total heat-load of the conditioned space is known (in
Btu/hr) we can find the total number of pounds of ("evaporated") (R)
refrigerant that must be circulated by the compressor and metered through
the evaporator coil.

The closer that Btu/hr match is, the more efficient the system "can be."
Many other factors determine overall efficient A/C operation.

It requires a specific level of heat to (boil) evaporate a particular
refrigerant. The amount of the heat-load on the DX-coil determines the
maximum amount of (R) refrigerant that a DX-coil can evaporate. A TXV
(R) metering devices will better adjust to the heat-load and help
protect the compressor from flood-back. Flow-rator metering devices will
flood the coil and usually destroy the compressor!

Many older gas furnaces had small blowers and motor HP and unloaded at
higher static pressures, along with under sized ductwork. Couple those
factors with dirty filters that begin to by-pass lint and you have blower
wheel blades and evaporator fins and coils insulated and even blocked. You
end up with a coil that is not evaporating but little liquid (R) to absorb
latent and sensible heat from the air.

You could have a 3-ton DX-coil (36,000-Btu/hr) only boiling enough (R) to
absorb one ton (12,000-Btu/hr of heat from the air.
If it only boils one-third the (R) per hour it will only absorb and transfer
to the condenser 1/3rd the Btu/hr of heat to the condenser.

Here is another scenario with the same result:
The beer-can-cold boy installs a unit on a home that has a very hot
interior. This time the blower is producing too much CFM per ton of cooling.
So he thinks he has to get the suction line beer-can-cold and begins to pour
I the (R). Later when the interior cools down and then return air filter
begins to load-up, the coil becomes flooded liquid (R) begins. Same
scenario, DX-coil, two-thirds flooded and only one-third of liquid (R)
vaporizing to absorb heat. (A rated three tons, becomes a one ton operating
system.)

When the relative humidity is high, the ability of the evaporator to absorb
latent heat increases. Later, I will graph the increased ratio as humidity
goes up. The latent capacity of an air-conditioner depends on the specific
engineering of that specific evaporator and condenser match. In a 75-F
conditioned space you need 55-F discharge supply air over a period of long
run-time, mixing with the 75-F air to reach the 50% RH point.
- udarrell - Darrell
--
Air Conditioning System - Excessive Airflow - Excessive Charge
http://www.udarrell.com/aircondition...e-airflow.html

Try not to be offended or die laughing.... but I'd like your permission to
rewire parts of this and post it for your consideration. I see a few things
that could be written more clearly.

--

Christopher A. Young
Learn more about Jesus
www.lds.org
www.mormons.com


"udarrell" wrote in message
...
How your 3-ton A/C could only be operating at One Ton (Awe, you're kidding;
NO I'm NOT!)
Only two of many diverse factors that can cause very low Btu/hr evaporator
heat-load absorption and transfer scenarios.

Every refrigerant has a "vaporization" heat absorption factor per pound.
This heat-absorption effect is rated in Btu per pound of refrigerant.
(Btu/lb); if the total heat-load of the conditioned space is known (in
Btu/hr) we can find the total number of pounds of ("evaporated") (R)
refrigerant that must be circulated by the compressor and metered through
the evaporator coil.

The closer that Btu/hr match is, the more efficient the system "can be."
Many other factors determine overall efficient A/C operation.

It requires a specific level of heat to (boil) evaporate a particular
refrigerant. The amount of the heat-load on the DX-coil determines the
maximum amount of (R) refrigerant that a DX-coil can evaporate. A TXV
(R) metering devices will better adjust to the heat-load and help
protect the compressor from flood-back. Flow-rator metering devices will
flood the coil and usually destroy the compressor!

Many older gas furnaces had small blowers and motor HP and unloaded at
higher static pressures, along with under sized ductwork. Couple those
factors with dirty filters that begin to by-pass lint and you have blower
wheel blades and evaporator fins and coils insulated and even blocked. You
end up with a coil that is not evaporating but little liquid (R) to absorb
latent and sensible heat from the air.

You could have a 3-ton DX-coil (36,000-Btu/hr) only boiling enough (R) to
absorb one ton (12,000-Btu/hr of heat from the air.
If it only boils one-third the (R) per hour it will only absorb and transfer
to the condenser 1/3rd the Btu/hr of heat to the condenser.

Here is another scenario with the same result:
The beer-can-cold boy installs a unit on a home that has a very hot
interior. This time the blower is producing too much CFM per ton of cooling.
So he thinks he has to get the suction line beer-can-cold and begins to pour
I the (R). Later when the interior cools down and then return air filter
begins to load-up, the coil becomes flooded liquid (R) begins. Same
scenario, DX-coil, two-thirds flooded and only one-third of liquid (R)
vaporizing to absorb heat. (A rated three tons, becomes a one ton operating
system.)

When the relative humidity is high, the ability of the evaporator to absorb
latent heat increases. Later, I will graph the increased ratio as humidity
goes up. The latent capacity of an air-conditioner depends on the specific
engineering of that specific evaporator and condenser match. In a 75-F
conditioned space you need 55-F discharge supply air over a period of long
run-time, mixing with the 75-F air to reach the 50% RH point.
- udarrell - Darrell
--
Air Conditioning System - Excessive Airflow - Excessive Charge
http://www.udarrell.com/aircondition...e-airflow.html

Try not to be offended or die laughing.... but I'd like your permission to
rewire parts of this and post it for your consideration. I see a few things
that could be written more clearly. I think the concept is great. But a few
things might not be easily understood.

--

Christopher A. Young
Learn more about Jesus
www.lds.org
www.mormons.com


"udarrell" wrote in message
...
How your 3-ton A/C could only be operating at One Ton (Awe, you're kidding;
NO I'm NOT!)
Only two of many diverse factors that can cause very low Btu/hr evaporator
heat-load absorption and transfer scenarios.

Every refrigerant has a "vaporization" heat absorption factor per pound.
This heat-absorption effect is rated in Btu per pound of refrigerant.
(Btu/lb); if the total heat-load of the conditioned space is known (in
Btu/hr) we can find the total number of pounds of ("evaporated") (R)
refrigerant that must be circulated by the compressor and metered through
the evaporator coil.

The closer that Btu/hr match is, the more efficient the system "can be."
Many other factors determine overall efficient A/C operation.

It requires a specific level of heat to (boil) evaporate a particular
refrigerant. The amount of the heat-load on the DX-coil determines the
maximum amount of (R) refrigerant that a DX-coil can evaporate. A TXV
(R) metering devices will better adjust to the heat-load and help
protect the compressor from flood-back. Flow-rator metering devices will
flood the coil and usually destroy the compressor!

Many older gas furnaces had small blowers and motor HP and unloaded at
higher static pressures, along with under sized ductwork. Couple those
factors with dirty filters that begin to by-pass lint and you have blower
wheel blades and evaporator fins and coils insulated and even blocked. You
end up with a coil that is not evaporating but little liquid (R) to absorb
latent and sensible heat from the air.

You could have a 3-ton DX-coil (36,000-Btu/hr) only boiling enough (R) to
absorb one ton (12,000-Btu/hr of heat from the air.
If it only boils one-third the (R) per hour it will only absorb and transfer
to the condenser 1/3rd the Btu/hr of heat to the condenser.

Here is another scenario with the same result:
The beer-can-cold boy installs a unit on a home that has a very hot
interior. This time the blower is producing too much CFM per ton of cooling.
So he thinks he has to get the suction line beer-can-cold and begins to pour
I the (R). Later when the interior cools down and then return air filter
begins to load-up, the coil becomes flooded liquid (R) begins. Same
scenario, DX-coil, two-thirds flooded and only one-third of liquid (R)
vaporizing to absorb heat. (A rated three tons, becomes a one ton operating
system.)

When the relative humidity is high, the ability of the evaporator to absorb
latent heat increases. Later, I will graph the increased ratio as humidity
goes up. The latent capacity of an air-conditioner depends on the specific
engineering of that specific evaporator and condenser match. In a 75-F
conditioned space you need 55-F discharge supply air over a period of long
run-time, mixing with the 75-F air to reach the 50% RH point.
- udarrell - Darrell
--
Air Conditioning System - Excessive Airflow - Excessive Charge
http://www.udarrell.com/aircondition...e-airflow.html

Please do so! It could probably be done more concisely in a couple of
sentences.
Like maybe B.S., huh, ha.

I am trying to get you guys more service work. (I know don't bother!)

I am not very well and may not be around too much longer.
You could make a good living retro fitting ductwork. - udarrell
--
Air Conditioning System - Excessive Airflow - Excessive Charge
http://www.udarrell.com/aircondition...e-airflow.html

"Stormin Mormon" wrote in message
...
Try not to be offended or die laughing.... but I'd like your permission
to
rewire parts of this and post it for your consideration. I see a few
things
that could be written more clearly.

--

Christopher A. Young
Learn more about Jesus
www.lds.org
www.mormons.com

"udarrell" wrote in message
...
How your 3-ton A/C could only be operating at One Ton (Awe, you're
kidding;
NO I'm NOT!)
Only two of many diverse factors that can cause very low Btu/hr evaporator
heat-load absorption and transfer scenarios.

Every refrigerant has a "vaporization" heat absorption factor per pound.
This heat-absorption effect is rated in Btu per pound of refrigerant.
(Btu/lb); if the total heat-load of the conditioned space is known (in
Btu/hr) we can find the total number of pounds of ("evaporated") (R)
refrigerant that must be circulated by the compressor and metered through
the evaporator coil.

The closer that Btu/hr match is, the more efficient the system "can be."
Many other factors determine overall efficient A/C operation.

It requires a specific level of heat to (boil) evaporate a particular
refrigerant. The amount of the heat-load on the DX-coil determines the
maximum amount of (R) refrigerant that a DX-coil can evaporate. A TXV
(R) metering devices will better adjust to the heat-load and help
protect the compressor from flood-back. Flow-rator metering devices will
flood the coil and usually destroy the compressor!

Many older gas furnaces had small blowers and motor HP and unloaded at
higher static pressures, along with under sized ductwork. Couple those
factors with dirty filters that begin to by-pass lint and you have blower
wheel blades and evaporator fins and coils insulated and even blocked. You
end up with a coil that is not evaporating but little liquid (R) to absorb
latent and sensible heat from the air.

You could have a 3-ton DX-coil (36,000-Btu/hr) only boiling enough (R) to
absorb one ton (12,000-Btu/hr of heat from the air.
If it only boils one-third the (R) per hour it will only absorb and
transfer
to the condenser 1/3rd the Btu/hr of heat to the condenser.

Here is another scenario with the same result:
The beer-can-cold boy installs a unit on a home that has a very hot
interior. This time the blower is producing too much CFM per ton of
cooling.
So he thinks he has to get the suction line beer-can-cold and begins to
pour
I the (R). Later when the interior cools down and then return air filter
begins to load-up, the coil becomes flooded liquid (R) begins. Same
scenario, DX-coil, two-thirds flooded and only one-third of liquid (R)
vaporizing to absorb heat. (A rated three tons, becomes a one ton
operating
system.)

When the relative humidity is high, the ability of the evaporator to
absorb
latent heat increases. Later, I will graph the increased ratio as humidity
goes up. The latent capacity of an air-conditioner depends on the specific
engineering of that specific evaporator and condenser match. In a 75-F
conditioned space you need 55-F discharge supply air over a period of long
run-time, mixing with the 75-F air to reach the 50% RH point.
- udarrell - Darrell

Okay, I will confess. The first part was a fake scenario. I exaggerated the
drop in Btu/hr tonnage to get a rise out of you guys.
Yes, it would freeze up an slug even a scroll compressor and a TXV before it
dropped the Btu/hr that far! Ha.
It is strange that nobody jumped on it sooner! I can't write anymore anyway.
Play with it though.
- udarrell
--
Air-Conditioning Efficiency "Optimizing evaporator Coil 'Heat-Load Btu/hr
first,' is critical"
http://www.udarrell.com/air-conditio...ator-coil.html

"Stormin Mormon" wrote in message
...
Try not to be offended or die laughing.... but I'd like your permission
to
rewire parts of this and post it for your consideration. I see a few
things
that could be written more clearly.

Christopher A. Young
Learn more about Jesus
www.lds.org
www.mormons.com

Okay, I will confess. The first part was a fake scenario. I exaggerated the
drop in Btu/hr tonnage to get a rise out of you guys.
Yes, it would freeze up an slug even a scroll compressor even with a
TXV, before it
dropped the Btu/hr that far! Ha.
If a TXV shut the flow down too much the compressor would over heat
unless a little liquid got through.
What is the situation concerning a scroll compressor's ability to pump a
small amount of liquid. I heard it is less likely to damage them.

On large low temp compressor I witnessed guys charging with liquid
through the suction line while the compressor was running.
Nothing to meter the flow on the hoses, either.
Oh yes, the compressor made some scary sounds but it didn't seem to
damage the valves. They said they did it all the time.
I didn't work a lot of low temp but would never have tried that.

It is strange that nobody jumped on it sooner! I can't write anymore anyway.
Play with it though.
- udarrell
--
Air-Conditioning Efficiency "Optimizing evaporator Coil 'Heat-Load Btu/hr
first,' is critical"
http://www.udarrell.com/air-conditio...ator-coil.html

"Stormin Mormon" wrote in message
...
Try not to be offended or die laughing.... but I'd like your permission
to
rewire parts of this and post it for your consideration. I see a few
things
that could be written more clearly.

Christopher A. Young
Learn more about Jesus
www.lds.org
www.mormons.com

"udarrell" wrote in message
...
Okay, I will confess. The first part was a fake scenario. I exaggerated the
drop in Btu/hr tonnage to get a rise out of you guys.
Yes, it would freeze up an slug even a scroll compressor and a TXV before it
dropped the Btu/hr that far! Ha.
It is strange that nobody jumped on it sooner! I can't write anymore anyway.
Play with it though.
- udarrell
--
Air-Conditioning Efficiency "Optimizing evaporator Coil 'Heat-Load Btu/hr
first,' is critical"
http://www.udarrell.com/air-conditio...ator-coil.html


This is Turtle.

I'm still Reading and Steady Eyeing it all about it flying.

TURTLE

Hi Turtle,
Well, I pushed the envelope a bit with the first scenario for a
reason, --primarily just to emphasis a point.
..
However, I run onto restricted systems that were producing varying degrees
of capacity done to near zip
The strange thing is that on a number of occasions the HO would say they had
it checked and they couldn't find anything wrong.

I will never forget the two GE condensers that I found with the strainer in
line to their aluminum condenser coils. The strainer was in the copper
portion ahead of the aluminum.
They had other techs check them with no results. I found the problems within
a couple minutes when those units wouldn't take a charge and were pulling
the suction down. Then there was the apartment unit with the orifice piston
put on in backward allowing liquid to bypass the orifice. That one produced
pressures similar to bad compressor valves. They thought the compressor was
bad but I suspected an oversized orifice or one stuck open or even left out.

I valved it off, and it pumped down and held, so I checked the
flow-rator-piston, put it in the proper way and it operated normally.

Depending on how bad the restriction is, the compressor in time will
overheat. If they get too hot too often the oil will break down resulting in
acid forming-compounds that will eventually destroy the system. -
udarrell - Darrell

--
Air-Conditioning Efficiency "Optimizing evaporator Coil 'Heat-Load Btu/hr
first,' is critical"
http://www.udarrell.com/air-conditio...ator-coil.html

"TURTLE" wrote in message
.. .

This is Turtle.
I'm still Reading and Steady Eyeing it all about it flying.
TURTLE

It won't fly too well Turtle, it was a scenario that was made primarily to
emphasis a point.
It should have generated some thoughtful responses, however what can one
expect when no one wants to discuss hvac.
Actually, it appears there were complaints filed against my post.
It least my post was about hvac within NO back biting! - Darrell