Last year the central AC went down. Compressor wouldn't atart and I was in the "oh ****" mode. However I found that the run capacitor was bad and it is up and running fine for about twenty bucks from the local W.W. Grainger. A simple dual AC 440 volt capacitor, not a compressor. Plus it's an R22 system which compicates matters even further. I would have had to convert to R134 or wait months for a compatible condensing unit.

Anyway now that the heat is on here again, the electric bill is not as high as last year it seems. Now I know capacitors don't all go all at once and I wonder now if decreased capacitance or high ESR might have been adversely affecting the unit's efficiency.

These motors are of course synchronous or whatever so they are going to do 1,750 or 3,450 RPM or whatever, so if less efficient then it would stand to reason that they would be pulling more current than they should.

How much can that weak capacitor cost you in energy ? This is not a start capacitor, it is a run capacitor. Would it be worth it, in these days of ever increasing energy costs to go out and actually check these capacitors and change them when they get marginal ?

J

wrote:

Last year the central AC went down. Compressor wouldn't atart and I was in the "oh ****" mode. However I found that the run capacitor was bad and it is up and running fine for about twenty bucks from the local W.W. Grainger. A simple dual AC 440 volt capacitor, not a compressor. Plus it's an R22 system which compicates matters even further. I would have had to convert to R134 or wait months for a compatible condensing unit.

Anyway now that the heat is on here again, the electric bill is not as high as last year it seems. Now I know capacitors don't all go all at once and I wonder now if decreased capacitance or high ESR might have been adversely affecting the unit's efficiency.

These motors are of course synchronous or whatever so they are going to do 1,750 or 3,450 RPM or whatever, so if less efficient then it would stand to reason that they would be pulling more current than they should.

How much can that weak capacitor cost you in energy ? This is not a start capacitor, it is a run capacitor. Would it be worth it, in these days of ever increasing energy costs to go out and actually check these capacitors and change them when they get marginal ?

J
Yes, it would cause the motor the exert more current than should be, if
the run cap were reduced in value. Also, makes it harder to start and
the compressor would operate slower..

Jamie

Jamie t wrote:
wrote:

Last year the central AC went down. Compressor wouldn't atart and I was
in the "oh ****" mode. However I found that the run capacitor was bad
and it is up and running fine for about twenty bucks from the local W.W.
Grainger. A simple dual AC 440 volt capacitor, not a compressor. Plus
it's an R22 system which compicates matters even further. I would have
had to convert to R134 or wait months for a compatible condensing unit.
Anyway now that the heat is on here again, the electric bill is not
as high as last year it seems. Now I know capacitors don't all go all
at once and I wonder now if decreased capacitance or high ESR might
have been adversely affecting the unit's efficiency. These motors
are of course synchronous or whatever so they are going to do 1,750 or
3,450 RPM or whatever, so if less efficient then it would stand to
reason that they would be pulling more current than they should.
How much can that weak capacitor cost you in energy ? This is not a
start capacitor, it is a run capacitor. Would it be worth it, in these
days of ever increasing energy costs to go out and actually check
these capacitors and change them when they get marginal ?
J
Yes, it would cause the motor the exert more current than should be, if
the run cap were reduced in value. Also, makes it harder to start and the
compressor would operate slower..

Jamie

I have not measured it this year, but I have been drawing 6 amps on my
compressor. If something changes the current should change. Good to
monitor.

Greg

On Jul 18, 4:54*pm, wrote:
Last year the central AC went down. Compressor wouldn't atart and I was in the "oh ****" mode. However I found that the run capacitor was bad and it is up and running fine for about twenty bucks from the local W.W. Grainger.. A simple dual AC 440 volt capacitor, not a compressor. Plus it's an R22 system which compicates matters even further. I would have had to convert to R134 or wait months for a compatible condensing unit.

Anyway now that the heat is on here again, the electric bill is not as high as last year it seems. Now I know capacitors don't all go all at once and I wonder now if decreased capacitance or high ESR might have been adversely affecting the unit's efficiency.

These motors are of course synchronous or whatever so they are going to do 1,750 or 3,450 RPM or whatever, so if less efficient then it would stand to reason that they would be pulling more current than they should.

How much can that weak capacitor cost you in energy ? This is not a start capacitor, it is a run capacitor. Would it be worth it, in these days of ever increasing energy costs to go out and actually check these capacitors and change them when they get marginal ?

J

I also have 3 zones of R22 A/C's. What brand is yours? Someone
'diddled' with the valve on zone 3 and f$500 worth of R22 [9.5 lb.]
went into the atmosphere. To replace unit to 'more efficient and
environmentally friendly' is at least $1700 arrrgggg!

Without freon the unit would not run. Repair people [from their
office] said probably capacitor, because it's the first thing to go
out. Hmmm.

When the guy came out he checked pressure on the working units, and
verified lack of freon prevented zone 3 form operating, but I never
saw him check the capacitors! Since a bad capacitor can impact
efficiency and is always the first thing to go, I'm surprised it's not
one of the first items to check. Any thoughts?

On Jul 19, 9:00*am, Robert Macy wrote:
On Jul 18, 4:54*pm, wrote:

Last year the central AC went down. Compressor wouldn't atart and I was in the "oh ****" mode. However I found that the run capacitor was bad and it is up and running fine for about twenty bucks from the local W.W. Grainger. A simple dual AC 440 volt capacitor, not a compressor. Plus it's an R22 system which compicates matters even further. I would have had to convert to R134 or wait months for a compatible condensing unit.

Anyway now that the heat is on here again, the electric bill is not as high as last year it seems. Now I know capacitors don't all go all at once and I wonder now if decreased capacitance or high ESR might have been adversely affecting the unit's efficiency.

These motors are of course synchronous or whatever so they are going to do 1,750 or 3,450 RPM or whatever, so if less efficient then it would stand to reason that they would be pulling more current than they should.

How much can that weak capacitor cost you in energy ? This is not a start capacitor, it is a run capacitor. Would it be worth it, in these days of ever increasing energy costs to go out and actually check these capacitors and change them when they get marginal ?

J

I also have 3 zones of R22 A/C's. *What brand is yours? *Someone
'diddled' with the valve on zone 3 and f$500 worth of R22 [9.5 lb.]
went into the atmosphere. *To replace unit to 'more efficient and
environmentally friendly' is at least $1700 *arrrgggg!

Without freon the unit would not run. Repair people [from their
office] said probably capacitor, because it's the first thing to go
out. *Hmmm.

When the guy came out he checked pressure on the working units, and
verified lack of freon prevented zone 3 form operating, but I never
saw him check the capacitors! *Since a bad capacitor can impact
efficiency and is always the first thing to go, I'm surprised it's not
one of the first items to check. *Any thoughts?

If the system has a relay that opens the circuit to the compressor
when the pressure is low, the tech might have made the correct first
move.

On Jul 19, 7:50*am, "hr(bob) "
wrote:
On Jul 19, 9:00*am, Robert Macy wrote:





On Jul 18, 4:54*pm, wrote:

Last year the central AC went down. Compressor wouldn't atart and I was in the "oh ****" mode. However I found that the run capacitor was bad and it is up and running fine for about twenty bucks from the local W.W. Grainger. A simple dual AC 440 volt capacitor, not a compressor. Plus it's an R22 system which compicates matters even further. I would have had to convert to R134 or wait months for a compatible condensing unit.

Anyway now that the heat is on here again, the electric bill is not as high as last year it seems. Now I know capacitors don't all go all at once and I wonder now if decreased capacitance or high ESR might have been adversely affecting the unit's efficiency.

These motors are of course synchronous or whatever so they are going to do 1,750 or 3,450 RPM or whatever, so if less efficient then it would stand to reason that they would be pulling more current than they should.

How much can that weak capacitor cost you in energy ? This is not a start capacitor, it is a run capacitor. Would it be worth it, in these days of ever increasing energy costs to go out and actually check these capacitors and change them when they get marginal ?

J

I also have 3 zones of R22 A/C's. *What brand is yours? *Someone
'diddled' with the valve on zone 3 and f$500 worth of R22 [9.5 lb.]
went into the atmosphere. *To replace unit to 'more efficient and
environmentally friendly' is at least $1700 *arrrgggg!

Without freon the unit would not run. Repair people [from their
office] said probably capacitor, because it's the first thing to go
out. *Hmmm.

When the guy came out he checked pressure on the working units, and
verified lack of freon prevented zone 3 form operating, but I never
saw him check the capacitors! *Since a bad capacitor can impact
efficiency and is always the first thing to go, I'm surprised it's not
one of the first items to check. *Any thoughts?

If the system has a relay that opens the circuit to the compressor
when the pressure is low, the tech might have made the correct first
move.

I was referring to the GOOD units. Why weren't the caps checked in any
manner on those units.

On Thu, 19 Jul 2012 08:51:56 -0700 (PDT), Robert Macy
wrote:

On Jul 19, 7:50*am, "hr(bob) "
wrote:
On Jul 19, 9:00*am, Robert Macy wrote:





On Jul 18, 4:54*pm, wrote:

Last year the central AC went down. Compressor wouldn't atart and I was in the "oh ****" mode. However I found that the run capacitor was bad and it is up and running fine for about twenty bucks from the local W.W. Grainger. A simple dual AC 440 volt capacitor, not a compressor. Plus it's an R22 system which compicates matters even further. I would have had to convert to R134 or wait months for a compatible condensing unit.

Anyway now that the heat is on here again, the electric bill is not as high as last year it seems. Now I know capacitors don't all go all at once and I wonder now if decreased capacitance or high ESR might have been adversely affecting the unit's efficiency.

These motors are of course synchronous or whatever so they are going to do 1,750 or 3,450 RPM or whatever, so if less efficient then it would stand to reason that they would be pulling more current than they should.

How much can that weak capacitor cost you in energy ? This is not a start capacitor, it is a run capacitor. Would it be worth it, in these days of ever increasing energy costs to go out and actually check these capacitors and change them when they get marginal ?

J

I also have 3 zones of R22 A/C's. *What brand is yours? *Someone
'diddled' with the valve on zone 3 and f$500 worth of R22 [9.5 lb.]
went into the atmosphere. *To replace unit to 'more efficient and
environmentally friendly' is at least $1700 *arrrgggg!

Without freon the unit would not run. Repair people [from their
office] said probably capacitor, because it's the first thing to go
out. *Hmmm.

When the guy came out he checked pressure on the working units, and
verified lack of freon prevented zone 3 form operating, but I never
saw him check the capacitors! *Since a bad capacitor can impact
efficiency and is always the first thing to go, I'm surprised it's not
one of the first items to check. *Any thoughts?

If the system has a relay that opens the circuit to the compressor
when the pressure is low, the tech might have made the correct first
move.

I was referring to the GOOD units. Why weren't the caps checked in any
manner on those units.
Time. The tech woul have had to kill the power to the other two
units, open them up, and check the cap. Under ideal circumstances
that would add another half hour of labor to the bill. Of course, you
appreciate the benefits of preventative care and would not have
questioned the extra $50 on the bill. Other, less intelligent people
would simply accuse the tech of padding the bill.

PlainBill

On Jul 19, 2:10*pm, wrote:
On Thu, 19 Jul 2012 08:51:56 -0700 (PDT), Robert Macy





wrote:
On Jul 19, 7:50*am, "hr(bob) "
wrote:
On Jul 19, 9:00*am, Robert Macy wrote:

On Jul 18, 4:54*pm, wrote:

Last year the central AC went down. Compressor wouldn't atart and I was in the "oh ****" mode. However I found that the run capacitor was bad and it is up and running fine for about twenty bucks from the local W.W. Grainger. A simple dual AC 440 volt capacitor, not a compressor. Plus it's an R22 system which compicates matters even further. I would have had to convert to R134 or wait months for a compatible condensing unit.

Anyway now that the heat is on here again, the electric bill is not as high as last year it seems. Now I know capacitors don't all go all at once and I wonder now if decreased capacitance or high ESR might have been adversely affecting the unit's efficiency.

These motors are of course synchronous or whatever so they are going to do 1,750 or 3,450 RPM or whatever, so if less efficient then it would stand to reason that they would be pulling more current than they should.

How much can that weak capacitor cost you in energy ? This is not a start capacitor, it is a run capacitor. Would it be worth it, in these days of ever increasing energy costs to go out and actually check these capacitors and change them when they get marginal ?

J

I also have 3 zones of R22 A/C's. *What brand is yours? *Someone
'diddled' with the valve on zone 3 and f$500 worth of R22 [9.5 lb.]
went into the atmosphere. *To replace unit to 'more efficient and
environmentally friendly' is at least $1700 *arrrgggg!

Without freon the unit would not run. Repair people [from their
office] said probably capacitor, because it's the first thing to go
out. *Hmmm.

When the guy came out he checked pressure on the working units, and
verified lack of freon prevented zone 3 form operating, but I never
saw him check the capacitors! *Since a bad capacitor can impact
efficiency and is always the first thing to go, I'm surprised it's not
one of the first items to check. *Any thoughts?

If the system has a relay that opens the circuit to the compressor
when the pressure is low, the tech might have made the correct first
move.

I was referring to the GOOD units. Why weren't the caps checked in any
manner on those units.

Time. *The tech woul have had to kill the power to the other two
units, open them up, and check the cap. *Under ideal circumstances
that would add another half hour of labor to the bill. *Of course, you
appreciate the benefits of preventative care and would not have
questioned the extra $50 on the bill. *Other, less intelligent people
would simply accuse the tech of padding the bill.

PlainBill

I never mind an added cost if it is 'additional', announced as
additional, and undertaken at my request.

However, I contracted with this firm to come out and CHECK my units at
a fixed price. Words mean something. "Check my units at $49.95 cost."
is exactly that. And, if this component does fail as often as claimed
and if this component does eat power as it fails; then it is
reasonable for me to assume that this component is and should be part
of the check when a tech comes out. After all, there's not much
difference between checking the cap and measuring the pressure except
one is electrical and the other mechanical. Retrospectively, surprised
power during operation was not measured and noted at least for future
reference.

Don't get me wrong, I got my money's worth with the single pressure
measurement that I can't make and enjoyed the education. Impressive to
me was after the tech measured the pressure he told me the temp inside
my house! May be obvious to those in the business, but pure magic to
me.

On Fri, 20 Jul 2012 07:21:04 -0700 (PDT), Robert Macy
wrote:

On Jul 19, 2:10*pm, wrote:
On Thu, 19 Jul 2012 08:51:56 -0700 (PDT), Robert Macy





wrote:
On Jul 19, 7:50*am, "hr(bob) "
wrote:
On Jul 19, 9:00*am, Robert Macy wrote:

On Jul 18, 4:54*pm, wrote:

Last year the central AC went down. Compressor wouldn't atart and I was in the "oh ****" mode. However I found that the run capacitor was bad and it is up and running fine for about twenty bucks from the local W.W. Grainger. A simple dual AC 440 volt capacitor, not a compressor. Plus it's an R22 system which compicates matters even further. I would have had to convert to R134 or wait months for a compatible condensing unit.

Anyway now that the heat is on here again, the electric bill is not as high as last year it seems. Now I know capacitors don't all go all at once and I wonder now if decreased capacitance or high ESR might have been adversely affecting the unit's efficiency.

These motors are of course synchronous or whatever so they are going to do 1,750 or 3,450 RPM or whatever, so if less efficient then it would stand to reason that they would be pulling more current than they should.

How much can that weak capacitor cost you in energy ? This is not a start capacitor, it is a run capacitor. Would it be worth it, in these days of ever increasing energy costs to go out and actually check these capacitors and change them when they get marginal ?

J

I also have 3 zones of R22 A/C's. *What brand is yours? *Someone
'diddled' with the valve on zone 3 and f$500 worth of R22 [9.5 lb.]
went into the atmosphere. *To replace unit to 'more efficient and
environmentally friendly' is at least $1700 *arrrgggg!

Without freon the unit would not run. Repair people [from their
office] said probably capacitor, because it's the first thing to go
out. *Hmmm.

When the guy came out he checked pressure on the working units, and
verified lack of freon prevented zone 3 form operating, but I never
saw him check the capacitors! *Since a bad capacitor can impact
efficiency and is always the first thing to go, I'm surprised it's not
one of the first items to check. *Any thoughts?

If the system has a relay that opens the circuit to the compressor
when the pressure is low, the tech might have made the correct first
move.

I was referring to the GOOD units. Why weren't the caps checked in any
manner on those units.

Time. *The tech woul have had to kill the power to the other two
units, open them up, and check the cap. *Under ideal circumstances
that would add another half hour of labor to the bill. *Of course, you
appreciate the benefits of preventative care and would not have
questioned the extra $50 on the bill. *Other, less intelligent people
would simply accuse the tech of padding the bill.

PlainBill

I never mind an added cost if it is 'additional', announced as
additional, and undertaken at my request.

However, I contracted with this firm to come out and CHECK my units at
a fixed price. Words mean something. "Check my units at $49.95 cost."
is exactly that. And, if this component does fail as often as claimed
and if this component does eat power as it fails; then it is
reasonable for me to assume that this component is and should be part
of the check when a tech comes out. After all, there's not much
difference between checking the cap and measuring the pressure except
one is electrical and the other mechanical. Retrospectively, surprised
power during operation was not measured and noted at least for future
reference.

Don't get me wrong, I got my money's worth with the single pressure
measurement that I can't make and enjoyed the education. Impressive to
me was after the tech measured the pressure he told me the temp inside
my house! May be obvious to those in the business, but pure magic to
me.
I beg to differ. The only 'cost' that was fixed was the amount you
were charged. Perhaps you have heard - 'Time is Money'. You MIGHT
have meant "Check all the units and bring them up to peak performance
for $49.95". What they certainly heard was either "Fix the
non-working unit for $49.95", or more likely "Find out what is wrong
with the non-working unit of $49.95 and tell me how much it will cost
to repair it".

Now, if you were taking advantage of a 'Spring AC checkup for $49.95',
I would agree you had a valid point.

PlainBill

Robert Macy wrote:


However, I contracted with this firm to come out and CHECK my units at
a fixed price. Words mean something. "Check my units at $49.95 cost."
is exactly that. And, if this component does fail as often as claimed
No, in general, I don't think the run caps are any more failure-prone
than any other part. I have had exactly ONE run cap blow in 40 years.
I have had a number of other things fail over that time. Also, if the cap
is not blown open like a grenade, exactly HOW do you check it? Probably
any time up to a minute before exploding, no test that won't harm it
will detect a unit nearing failure.

Jon

On Jul 20, 8:58*am, wrote:
On Fri, 20 Jul 2012 07:21:04 -0700 (PDT), Robert Macy





wrote:
On Jul 19, 2:10*pm, wrote:
On Thu, 19 Jul 2012 08:51:56 -0700 (PDT), Robert Macy

wrote:
On Jul 19, 7:50*am, "hr(bob) "
wrote:
On Jul 19, 9:00*am, Robert Macy wrote:

On Jul 18, 4:54*pm, wrote:

Last year the central AC went down. Compressor wouldn't atart and I was in the "oh ****" mode. However I found that the run capacitor was bad and it is up and running fine for about twenty bucks from the local W.W.. Grainger. A simple dual AC 440 volt capacitor, not a compressor. Plus it's an R22 system which compicates matters even further. I would have had to convert to R134 or wait months for a compatible condensing unit.

Anyway now that the heat is on here again, the electric bill is not as high as last year it seems. Now I know capacitors don't all go all at once and I wonder now if decreased capacitance or high ESR might have been adversely affecting the unit's efficiency.

These motors are of course synchronous or whatever so they are going to do 1,750 or 3,450 RPM or whatever, so if less efficient then it would stand to reason that they would be pulling more current than they should.

How much can that weak capacitor cost you in energy ? This is not a start capacitor, it is a run capacitor. Would it be worth it, in these days of ever increasing energy costs to go out and actually check these capacitors and change them when they get marginal ?

J

I also have 3 zones of R22 A/C's. *What brand is yours? *Someone
'diddled' with the valve on zone 3 and f$500 worth of R22 [9.5 lb..]
went into the atmosphere. *To replace unit to 'more efficient and
environmentally friendly' is at least $1700 *arrrgggg!

Without freon the unit would not run. Repair people [from their
office] said probably capacitor, because it's the first thing to go
out. *Hmmm.

When the guy came out he checked pressure on the working units, and
verified lack of freon prevented zone 3 form operating, but I never
saw him check the capacitors! *Since a bad capacitor can impact
efficiency and is always the first thing to go, I'm surprised it's not
one of the first items to check. *Any thoughts?

If the system has a relay that opens the circuit to the compressor
when the pressure is low, the tech might have made the correct first
move.

I was referring to the GOOD units. Why weren't the caps checked in any
manner on those units.

Time. *The tech woul have had to kill the power to the other two
units, open them up, and check the cap. *Under ideal circumstances
that would add another half hour of labor to the bill. *Of course, you
appreciate the benefits of preventative care and would not have
questioned the extra $50 on the bill. *Other, less intelligent people
would simply accuse the tech of padding the bill.

PlainBill

I never mind an added cost if it is 'additional', announced as
additional, and undertaken at my request.

However, I contracted with this firm to come out and CHECK my units at
a fixed price. Words mean something. "Check my units at $49.95 cost."
is exactly that. And, if this component does fail as often as claimed
and if this component does eat power as it fails; then it is
reasonable for me to assume that this component is and should be part
of the check when a tech comes out. After all, there's not much
difference between checking the cap and measuring the pressure except
one is electrical and the other mechanical. Retrospectively, surprised
power during operation was not measured and noted at least for future
reference.

Don't get me wrong, I got my money's worth with the single pressure
measurement that I can't make and enjoyed the education. Impressive to
me was after the tech measured the pressure he told me the temp inside
my house! *May be obvious to those in the business, but pure magic to
me.

I beg to differ. *The only 'cost' that was fixed was the amount you
were charged. *Perhaps you have heard - 'Time is Money'. *You MIGHT
have meant "Check all the units and bring them up to peak performance
for $49.95". *What they certainly heard was either "Fix the
non-working unit for $49.95", or more likely "Find out what is wrong
with the non-working unit of $49.95 and tell me how much it will cost
to repair it".

Now, if you were taking advantage of a 'Spring AC checkup for $49.95',
I would agree you had a valid point.

PlainBill

Wow! and, English is my primary language!
Your last paragraph was closest.

I found the zone 3 not working, called the company. THEY offered the
fixed price to review ALL the units *and* "...while he's there doing
the two working units, the tech can see if he can find out what's
wrong, that way you won't be charged for just coming out to look at a
non-functional unit." so it was my understanding, and I blelieve
their understanding, that the tech was coming out to check 2
functioning zones and while he's here take a look at the non-
functioning unit to see if he can see what's wrong and quote on
repair.

But, after reading about the cap, seems like the 'health' of the cap
is more important than the exact pressure values.

Jon Elson wrote:

Robert Macy wrote:

However, I contracted with this firm to come out and CHECK my units at
a fixed price. Words mean something. "Check my units at $49.95 cost."
is exactly that. And, if this component does fail as often as claimed
No, in general, I don't think the run caps are any more failure-prone
than any other part. I have had exactly ONE run cap blow in 40 years.
I have had a number of other things fail over that time. Also, if the cap
is not blown open like a grenade, exactly HOW do you check it? Probably
any time up to a minute before exploding, no test that won't harm it
will detect a unit nearing failure.


Test the ESR, like any electrolytic.

On Jul 20, 12:10*pm, Jon Elson wrote:
Robert Macy wrote:
However, I contracted with this firm to come out and CHECK my units at
a fixed price. Words mean something. "Check my units at $49.95 cost."
is exactly that. And, if this component does fail as often as claimed

No, in general, I don't think the run caps are any more failure-prone
than any other part. *I have had exactly ONE run cap blow in 40 years.
I have had a number of other things fail over that time. *Also, if the cap
is not blown open like a grenade, exactly HOW do you check it? *Probably
any time up to a minute before exploding, no test that won't harm it
will detect a unit nearing failure.

Jon

Interesting, the service/repair company claimed cap was one of the
major reasons for a unit to fail to run at all.

In electronic applications it is often possible to measure the cap in
situ, and determine its 'health' to a degree. My understanding is that
the standard failure mechanism is the esr starts increasing, the cap
dissipates more power, getting hotter the esr continues to increase,
and eventually POP. Starts as low as 10-30 milliohms then can climb up
passed 1-2 ohms depending. There are a whole bunch of DIY projects to
make inexpensive esr cap measurment instrumentation.

On Fri, 20 Jul 2012 16:05:35 -0700 (PDT), Robert Macy
wrote:

On Jul 20, 8:58*am, wrote:
On Fri, 20 Jul 2012 07:21:04 -0700 (PDT), Robert Macy





wrote:
On Jul 19, 2:10*pm, wrote:
On Thu, 19 Jul 2012 08:51:56 -0700 (PDT), Robert Macy

wrote:
On Jul 19, 7:50*am, "hr(bob) "
wrote:
On Jul 19, 9:00*am, Robert Macy wrote:

On Jul 18, 4:54*pm, wrote:

Last year the central AC went down. Compressor wouldn't atart and I was in the "oh ****" mode. However I found that the run capacitor was bad and it is up and running fine for about twenty bucks from the local W.W. Grainger. A simple dual AC 440 volt capacitor, not a compressor. Plus it's an R22 system which compicates matters even further. I would have had to convert to R134 or wait months for a compatible condensing unit.

Anyway now that the heat is on here again, the electric bill is not as high as last year it seems. Now I know capacitors don't all go all at once and I wonder now if decreased capacitance or high ESR might have been adversely affecting the unit's efficiency.

These motors are of course synchronous or whatever so they are going to do 1,750 or 3,450 RPM or whatever, so if less efficient then it would stand to reason that they would be pulling more current than they should.

How much can that weak capacitor cost you in energy ? This is not a start capacitor, it is a run capacitor. Would it be worth it, in these days of ever increasing energy costs to go out and actually check these capacitors and change them when they get marginal ?

J

I also have 3 zones of R22 A/C's. *What brand is yours? *Someone
'diddled' with the valve on zone 3 and f$500 worth of R22 [9.5 lb.]
went into the atmosphere. *To replace unit to 'more efficient and
environmentally friendly' is at least $1700 *arrrgggg!

Without freon the unit would not run. Repair people [from their
office] said probably capacitor, because it's the first thing to go
out. *Hmmm.

When the guy came out he checked pressure on the working units, and
verified lack of freon prevented zone 3 form operating, but I never
saw him check the capacitors! *Since a bad capacitor can impact
efficiency and is always the first thing to go, I'm surprised it's not
one of the first items to check. *Any thoughts?

If the system has a relay that opens the circuit to the compressor
when the pressure is low, the tech might have made the correct first
move.

I was referring to the GOOD units. Why weren't the caps checked in any
manner on those units.

Time. *The tech woul have had to kill the power to the other two
units, open them up, and check the cap. *Under ideal circumstances
that would add another half hour of labor to the bill. *Of course, you
appreciate the benefits of preventative care and would not have
questioned the extra $50 on the bill. *Other, less intelligent people
would simply accuse the tech of padding the bill.

PlainBill

I never mind an added cost if it is 'additional', announced as
additional, and undertaken at my request.

However, I contracted with this firm to come out and CHECK my units at
a fixed price. Words mean something. "Check my units at $49.95 cost."
is exactly that. And, if this component does fail as often as claimed
and if this component does eat power as it fails; then it is
reasonable for me to assume that this component is and should be part
of the check when a tech comes out. After all, there's not much
difference between checking the cap and measuring the pressure except
one is electrical and the other mechanical. Retrospectively, surprised
power during operation was not measured and noted at least for future
reference.

Don't get me wrong, I got my money's worth with the single pressure
measurement that I can't make and enjoyed the education. Impressive to
me was after the tech measured the pressure he told me the temp inside
my house! *May be obvious to those in the business, but pure magic to
me.

I beg to differ. *The only 'cost' that was fixed was the amount you
were charged. *Perhaps you have heard - 'Time is Money'. *You MIGHT
have meant "Check all the units and bring them up to peak performance
for $49.95". *What they certainly heard was either "Fix the
non-working unit for $49.95", or more likely "Find out what is wrong
with the non-working unit of $49.95 and tell me how much it will cost
to repair it".

Now, if you were taking advantage of a 'Spring AC checkup for $49.95',
I would agree you had a valid point.

PlainBill

Wow! and, English is my primary language!
Your last paragraph was closest.

I found the zone 3 not working, called the company. THEY offered the
fixed price to review ALL the units *and* "...while he's there doing
the two working units, the tech can see if he can find out what's
wrong, that way you won't be charged for just coming out to look at a
non-functional unit." so it was my understanding, and I blelieve
their understanding, that the tech was coming out to check 2
functioning zones and while he's here take a look at the non-
functioning unit to see if he can see what's wrong and quote on
repair.

But, after reading about the cap, seems like the 'health' of the cap
is more important than the exact pressure values.
First of all, in the situation you describe, you are correct. If the
cap is a known high failure rate component it should have been
checked.

My Dad was the refrigeration expert, but from what I understand there
are a few tests that can be done to detect problems. The two most
common are the temperature drop across the evaporator and the high
side / low side pressure differential. The current draw may be an
indicator of the health of the system, but comparative readings would
probably have to be made.

A little research indicates the start capacitor is always an
electrolytic, while the run capacitor is usually a film cap. The most
effective test would be to check the capacitance, which would involve
more work than checking temperatures, pressures, or even current.
Which is probably why the tech didn't do it.

I'm not sure about the capacitance vrs expected life curve, but the
odds are it is very non-linear - with the final drop being very
abrupt.

PlainBill

Robert Macy wrote:



Interesting, the service/repair company claimed cap was one of the
major reasons for a unit to fail to run at all.

In electronic applications it is often possible to measure the cap in
situ, and determine its 'health' to a degree. My understanding is that
the standard failure mechanism is the esr starts increasing, the cap
dissipates more power, getting hotter the esr continues to increase,
and eventually POP. Starts as low as 10-30 milliohms then can climb up
passed 1-2 ohms depending. There are a whole bunch of DIY projects to
make inexpensive esr cap measurment instrumentation.
There may be certain brands or manufacturing date ranges where the
run caps are the most common point of failure. Most of my experience
is with older systems, in fact my house has two zones of 36 year old
Bryant A/Cs, and each year I expect to be the last for them, but they
keep soldiering on. I did blow a compressor run cap about 5 years ago.

But, my understanding of these oil-paper caps is that through thermal
cycling they eventually develop pinholes in the paper and the cap
goes from completely nominal to shorted within a single power line cycle.
So, unlike electrolytics that suffer slow loss of water in the electrolyte,
you DON'T get any warning or measurable degradation of the cap.

Jon

On Jul 25, 12:27*pm, Jon Elson wrote:
Robert Macy wrote:

Interesting, the service/repair company claimed cap was one of the
major reasons for a unit to fail to run at all.

In electronic applications it is often possible to measure the cap in
situ, and determine its 'health' to a degree. My understanding is that
the standard failure mechanism is the esr starts increasing, the cap
dissipates more power, getting hotter the esr continues to increase,
and eventually POP. Starts as low as 10-30 milliohms then can climb up
passed 1-2 ohms depending. *There are a whole bunch of DIY projects to
make inexpensive esr cap measurment instrumentation.

There may be certain brands or manufacturing date ranges where the
run caps are the most common point of failure. *Most of my experience
is with older systems, in fact my house has two zones of 36 year old
Bryant A/Cs, and each year I expect to be the last for them, but they
keep soldiering on. *I did blow a compressor run cap about 5 years ago.

But, my understanding of these oil-paper caps is that through thermal
cycling they eventually develop pinholes in the paper and the cap
goes from completely nominal to shorted within a single power line cycle.
So, unlike electrolytics that suffer slow loss of water in the electrolyte,
you DON'T get any warning or measurable degradation of the cap.

Jon

Good explanation.

Interesting challange: how to 'stress' test for 'weakness' WITHOUT
destroying.

I wonder if low energy HV would do it. At least IF a pinhole were
developing. the test would pop through, possibly without killing the
cap, then again, if the cap died while you're there testing it, maybe
that's better, since you're there and can replace it. Hmmm, rates up
there with the car mechanic who pulls on your radiator hose to tear it
loose to show you that your radiator hose is aged and will
break ...some day.

Robert Macy wrote:

Interesting challange: how to 'stress' test for 'weakness' WITHOUT
destroying.


Run the rated AC current through it an monitor the temperature. That
will also have it at the maximum operating voltage.


I wonder if low energy HV would do it. At least IF a pinhole were
developing. the test would pop through, possibly without killing the
cap, then again, if the cap died while you're there testing it, maybe
that's better, since you're there and can replace it. Hmmm, rates up
there with the car mechanic who pulls on your radiator hose to tear it
loose to show you that your radiator hose is aged and will
break ...some day.


Why not just replace it if you think it's old enough to fail? I've
seen them with bad connections to the foil, and they arced until the
heat blew the terminal board off the end of the can. New caps should be
film, not oil & paper.


Rubber hoses are reinforced with cotton fiber. If the hose is so bad
that he can pull it apart, it's already defective.

On Wed, 25 Jul 2012 14:27:25 -0500, Jon Elson wrote:

Robert Macy wrote:



Interesting, the service/repair company claimed cap was one of the
major reasons for a unit to fail to run at all.

In electronic applications it is often possible to measure the cap in
situ, and determine its 'health' to a degree. My understanding is that
the standard failure mechanism is the esr starts increasing, the cap
dissipates more power, getting hotter the esr continues to increase,
and eventually POP. Starts as low as 10-30 milliohms then can climb up
passed 1-2 ohms depending. There are a whole bunch of DIY projects to
make inexpensive esr cap measurment instrumentation.
There may be certain brands or manufacturing date ranges where the
run caps are the most common point of failure. Most of my experience
is with older systems, in fact my house has two zones of 36 year old
Bryant A/Cs, and each year I expect to be the last for them, but they
keep soldiering on. I did blow a compressor run cap about 5 years ago.

But, my understanding of these oil-paper caps is that through thermal
cycling they eventually develop pinholes in the paper and the cap
goes from completely nominal to shorted within a single power line cycle.
So, unlike electrolytics that suffer slow loss of water in the electrolyte,
you DON'T get any warning or measurable degradation of the cap.

Jon

In oil-paper capacitors the paper is just a physical separator and the oil
is the dielectric. The oil would refill the pinhole and little change
results. They are considered self-healing for this property. ESR from
"foil" degradation is the real enemy. They are designed to blow open when
there is excessive heat build up.

?-)

On Jul 27, 12:29*am, josephkk wrote:
On Wed, 25 Jul 2012 14:27:25 -0500, Jon Elson wrote:
Robert Macy wrote:

Interesting, the service/repair company claimed cap was one of the
major reasons for a unit to fail to run at all.

In electronic applications it is often possible to measure the cap in
situ, and determine its 'health' to a degree. My understanding is that
the standard failure mechanism is the esr starts increasing, the cap
dissipates more power, getting hotter the esr continues to increase,
and eventually POP. Starts as low as 10-30 milliohms then can climb up
passed 1-2 ohms depending. *There are a whole bunch of DIY projects to
make inexpensive esr cap measurment instrumentation.
There may be certain brands or manufacturing date ranges where the
run caps are the most common point of failure. *Most of my experience
is with older systems, in fact my house has two zones of 36 year old
Bryant A/Cs, and each year I expect to be the last for them, but they
keep soldiering on. *I did blow a compressor run cap about 5 years ago..

But, my understanding of these oil-paper caps is that through thermal
cycling they eventually develop pinholes in the paper and the cap
goes from completely nominal to shorted within a single power line cycle..
So, unlike electrolytics that suffer slow loss of water in the electrolyte,
you DON'T get any warning or measurable degradation of the cap.

Jon

In oil-paper capacitors the paper is just a physical separator and the oil
is the dielectric. *The oil would refill the pinhole and little change
results. *They are considered self-healing for this property. *ESR from
"foil" degradation is the real enemy. *They are designed to blow open when
there is excessive heat build up.

?-)

That means simply monitoring the esr will indicate 'health' of the cap.