HVAC capacitor questions

I have a 4 ton Carrier A/C that the original GE cap (Dual 60uF/5uF 440VAC)
went out last summer in ~May. It was about 6 years old. The top was bulged
badly so it was pretty clear the capacitor was bad.

Went to granger and found a Dayton capacitor that had the same ratings but
slightly smaller diameter (2.5 vs 2.75").

http://www.grainger.com/Grainger/DAYTON-Dual-Motor-Run-Capacitor-2MEK6

For $25 I figured what the heck. Cap worked great through the drought and
100+ Houston TX temperatures of 2011 and the temperatures of this summer,
not as hot but it is south Texas.

Well that cap died last night and of course on a Sunday granger is closed so
a borrowed window unit is keeping life support for now.

My question is:

Dual caps have essentially two caps in one package. My understanding this
is just for convenience of mounting and shortened assembly/repair times.

Looking at single 60uF 440V caps they are almost the same size as the dual
capacitor I have now. Do you think going with two separate capacitors would
be more reliable than going back with a Dual cap since not tradeoffs need to
be made to fit in a certain package size?

I found that Granger now stocks the GE dual cap (Genteq)
http://www.grainger.com/Grainger/GENTEQ-Motor-Run-Capacitor-5CNC5


These are the two separate single caps. Costs more but if its more reliable
I'll give it a try.
http://www.grainger.com/Grainger/GENTEQ-Motor-Run-Capacitor-5CNC4

http://www.grainger.com/Grainger/GENTEQ-Motor-Run-Capacitor-5CMY2



What do you guys think?

 

Not sure which quality is better. But ... methinks ... this time you
should buy _two_ sets so that when it goes kablouie on a hot Friday
night the missus ain't gonna be unhappy. Then you could walk out there,
fix it in minutes, and be the family hero

Note to self: Got to buy spare float valve for evap cooler. Same reason.

 

That is the plan. Being the perpetual cheapo I fond something that will
satisfy the cheapo in me and get the redundancy I need for next time.

I going the easy route and getting the dual Genteq tomorrow for ~$35 then
trying this guy as a backup

http://www.ebay.com/itm/Run-Capacit...983?pt=LH_DefaultDomain_0&hash=item1c29c2ca8f

I tool a look at QE Quality capacitors website and it look pretty decent.
Assuming its all true.

Not bad for a backup to allow me to get through a weekend before I get a new
replacement.

 

Obvious answer.. don't be the cheapo, buy a real film cap that'll last ten
years. It won't even cost ten times more!

Tim

 

Suggestions? What is a real film cap? Are you talking about the black
plastic bricks with the cap potted inside

http://www.sourcingmap.com/larger_i...100ux0202_ux_&p=236842&products_imageType=jpg


I have wondered about the internal construction of metal packaged A/C caps
vs the potted film run capacitors. The metal can ones are sometimes
referred to as film as well.

I wondered if it wise to use these with an outside A/C unit.

My understanding is that the traditional metal can A/C caps are built that
way so when they fail the tops bulge out and break the electrical
connections inside thereby isolating the fault.

Would those black plastic ones just catch on fire when hooked to a 40A
circuit?

 

And write down where it was purchased and file that into a manila folder
that says "A/C" or something on there. I neglected to do that on faucet
rubbers because when moving to the US I could only by a 25-pack (only
one faucet leaked when we bought the house). So I thought this is going
to last a lifetime ... *wrong* ... used the last one a while ago. The
water here is so chlorinated it literally eats rubber.

Luckily we have the oldest hardware store west of the Mississippi right
here. If they ain't got it then it doesn't exist

http://www.flickr.com/photos/fountain-tallman/
http://moonshinejunkyard.blogspot.com/2010/08/tuesdays-in-my-town-placerville.html

 

Can't you remodel it to use an inverter? When I had to replace our
central ventilation unit I choose a model with an inverter. I replaced
the capacitors on the previous one several times.

 

AFAIK, film caps (the film-in-oil, metal can type) last essentially forever.
I don't know about 40A, but I'd be surprised if a film cap operated at 140F
ambient didn't last more than 20 years.

The small physical size suggests to me that, at least the start section, is
a bipolar electrolytic, which is typically used for motor-start
applications, and short lived (not only at the >40A surge, but even just
being at 140F ambient for a few years).

The 30uF 370V can I've got sitting in my junk box is about 1-1/4" thick,
2-1/2" wide (oval shape) and 4" tall. Unless they've really changed the
game with film thickness these days, I don't see 60uF 440V fitting in a much
smaller package unless it's electrolytic. (The run part might still be film
though.)

Obviously, you'd need the space to fit such a capacitor...

Tim

 

It was damn cold on Saturday even deep inland in the bay area. I was in
Livermore freezing in the sub-70 deg F weather. Brrrr!

When I see those tubby nudists in the fog on Baker Beach, I have to say WTF.

 

I never heard of an inverter in an air conditioner, but the wiki seems
to make sense:

I suspect the air conditioning itself is better since it is a continuous
flow versus duty cycle modulation. [There are some high end
refrigerators that run continuously with what I guess is a similar scheme.]

Those AC caps fail a lot. I know quiet a few Ca to Nv transplants, and
they are routinely replacing the AC cap. Since an air conditioner really
only lasts about 15 years, it would be wise to go inverter for the
replacement. I assume heat pumps have similar schemes.

 

Something like these? Price isn't too bad.


http://www.cde.com/catalogs/SF.pdf

 

Yes, and many others; I believe mine are old (not PCBs-old) GE parts (which
I guess are Genteq or something now).

Tim

 

Just realized I got snookered by Grainger. They labeled the cap Genteq when
actually they are Proline. Both made by the same manufacturer that makes GE
but the lifetime spec on the Genteq is 60K hours while the lifetime spec on
the Proline is 10K hours.


Let see, 8700 hours in a year... Houston tx,..figure 5000 hours a year run
time... 2 years before I can expect this guy to pop IF it meets its
specifications. Genteqs sell for the same price ~$35 on other places
besides Grainger.


Oh well. I have my $11 china cheapo (Qe Quality) will be arriving Friday as
a backup. Next purchase will be something like the CDE caps. At least a
known name in the capacitor business.

 

Nope.. That's a run cap. A start cap would be the type used
with a hard start kit.
The caps they make these days are cheap and don't last.
Even the better brands are pretty much junk these days.
One thing I would do is use 440v rated caps vs 370v.
I think they tend to last a bit longer before going kaput.

 

Nope... The 60 mf is the run cap for the compressor. The 5 mf
is the run cap for the fan motor.

 

Not that I recall.. I said it though. Why? Because one
said the cap was a start cap, which it is not, and then
you claimed that the 5 mf was the run cap, and the 60 mf
was a start cap. Neither statement was correct.
And we don't want no incorrectness on this here interweb,
now do we.

 

That is not what he has. Why would I care about obtuse examples
that have nothing to do with what he has?

 

I know *exactly* what he has. He told us in the first post.
I Quote..

"I have a 4 ton Carrier A/C that the original GE cap (Dual 60uF/5uF 440VAC)"

And for the usual residential type condensing unit, yes, a
compressor motor with two run caps would be quite obtuse.
Like a pretty much zero chance of seeing one.

Almost all modern compressor motors use a single run cap,
and if starting is an issue, they add a start kit, which is a
start cap with a potential relay. Or they can slap a single
piece start kit with a start cap and a S/S relay built on top.
Not two run caps!

None of the usual fan motors in a modern condensing unit use two run
caps. Zero. None. Nada.

I don't know where you get your information, and I really don't care.
I've been working on air conditioners since 1977.
Only for a couple of years in the late 80's, when I owned a different
business, did I take a break from working on air conditioners, from the
overall time period 1977 until 2012.

I currently work on air conditioners, and I change out so many caps
that's it's almost become a new sideline due to the pathetic quality of
caps in the last few years. I make a lot of money due to these cheap
ass caps. Easy money my man, very easy money...

I've been in business long enough to remember when you rarely saw
bad caps.
I change some poor bastards, or bastardette, if they don't have
hairy legs, blown out A/C cap almost every single freakin day!!!
Some days, more than one case.
I change so many that I have to keep a complete stock of every common
value on the truck to avoid making store runs, and to make sure I have
one when it's 8:39 in the PM and after store hours.
How many A/C caps do you change out a week?

Why do you insist on humping my legs over silly ass A/C caps?
Sometimes when I'm in some bastards backyard changing an A/C cap, dogs
try to do that... :/ I think from now on, I'll ask them..
Hey doggy! are you happy to see me, or is your name Michael A. Terrell?

 

No, a typical response to a person that repeatedly tries to hump
my legs.
All I said to the other poster was that it was not a start cap,
but actually a run cap, and that caps in general are cheap and of
poor quality. And you seem to have some problem, and keep asking me
idiotic questions about parts that don't exist for the persons unit.

You don't know me for jack, and you have no idea what the quality
of my work is.
Almost everyone I do work for calls me back, and I get many
referrals. I have enough work just from existing customers that
know us, I don't have to advertise. And my prices to change a cap
are probably among the lowest in this city. I know some companies
that charge ridiculous prices. We don't. It's still good money
being it takes about 3 minutes to do.
All of the new equipment I install is permitted and inspected by the
city, and trust me, if something is not kosher, they will let you know
about it.

You are the one with the bad attitude. You obviously got bent over
by some unscrupulous moron HVAC tech, and you think everyone operates
that way. I'm sure you could also say the same thing about certain
TV techs too..
Fake screen name? Chortle.. You kill me, you really do. :|

 

Do that hard start caps replace the 60uF compressor run cap or go in
parallel with it until the compressor starts then drops out?

I've heard some negative pres about kickstart caps causing more problems
than they fix. Do you have experience with these lasting long term?