Thanks. I don't think 10% deviation will allow use of the next size up or down. 35uF to 40uF is larger than 10%.

Just curious - what does the cap do for operation of the pump? And what happens if you use a larger cap vs spec? Smaller cap vs spec?

The AC guy who recharged my system several years ago said replacing a cap would cost about $400 through them. He recommended just buying the part and replacing it myself as long as I was comfortable doing so. With all the help here, it's a piece of cake

Capacitors are like balloons, storing and releasing energy at 60 hz. They provide phase shift for single phase motors to help them start.

quote:

Dumb question: If they didn't have my size in stock (35+5), can I use a different size, at least temporarily? Or is that very bad? Not sure which way would be okay - 40+5? 30+5? How much different would be okay if the one I need is not in stock?

Good to hear your AC is back on.
Use of the next size up is ok. Best to stay in spec.
FYI, typical voltage ratings on caps is 370, there is 440v also and the higher voltage is what I prefer.
As for life expectancy, They are making them cheaper now. They use to last forever.

You can still buy a good capacitor, but nobody wants to pay the price. If you’re ok replacing caps, keep using the cheap Chinese ones. Even the manufacturers are doing this. I bought a new condenser and even it had a Chinese Titan cap.

If you want the best capacitor, you can buy an AmRad easily on Amazon. These are the gold standard, are made in the USA, but cost about twice as much as a Chinese one. There’s also Capcom (the old GE brand) that are made in Mexico. The AmRad Turbo 200 is adaptable to almost any need, with a Turbo Mini for really small applications (like the fan), the Turbo 200, and even the monster Turbo 200x for large applications which can go up 97.5 MFD. Best, however, to buy the exact size dual cap that you need.

Having the correct capacitor is essential to properly shifting the electrical phase. Putting in the wrong sized cap is analogous to saying “I’m all out of gasoline, but this diesel should work, right? It has more energy so it must be better.” The capacitor’s purpose is to time energy for the secondary winding. Using a capacitor out-of-spec causes that winding to “fire”, so to speak, at the wrong time, causing that secondary winding to be less effective at best, or harmful at worst. This will cause the motor to have difficulty starting, and cause it to run hot as the primary winding has to do the majority of the work. All this leads to premature motor failure.

Capacitors would be unnecessary if we had universal three-phase in all our homes, but because we don’t, we use capacitors to mimic a secondary phase.

I haven’t seen a cap recently that wasn’t rated for 440 EMF voltage. This is a max voltage, so it is fine to use a 440 on a 370 system. In fact, it confused so many people that the manufacturers started labeling them 370/440. As an aside, this voltage refers to the back voltage created by a spinning motor, since while a motor does its work, it still acts as a generator and generates a back voltage as it runs.

quote:

Originally posted by konata88:
Dumb question: If they didn't have my size in stock (35+5), can I use a different size, at least temporarily? Or is that very bad? Not sure which way would be okay - 40+5? 30+5? How much different would be okay if the one I need is not in stock?

I got lucky this time and bought the last one.

My coworker shared this with me, and it's what I keep on the shelf in my garage.

As previously posted, AmRad is made in the USA capacitors which for me prioritizes them above Chinese capacitors.

I could have bought the exact AmRad for my HVAC units but they were both replaced under warranty and I'm retiring in 3.5 to 5.5 years. AmRad Makes a Universal motor run capacitor that will work on my current units, would work on my neighbor's units (I would sell to them if theirs went out), and would work on the unit wherever I retire. It's more money but the flexibility was worth it for me. Link to AmRad Turbo 200 Universal Capacitor

Sorry - I'm not very technical. So the AmRad 200 can support my specific config of 35+5 by using the appropriate 3 leads? Or would I have to do some re-wiring?

Thanks for the education above. So, I didn't really understand it (sounds like the cap would provide power when the pump is not ready for it) but the gist sounds like - use only the spec'ed values. Don't use other caps even temporarily.

I'll look into an AmRad spare but the unit is about 24 years old now. Not sure if it's due for replacement or just keep replacing parts as they break. I guess the big one would be the pump (I'd have to hire the man for that).

The Turbo 200 is best for people with multiple units and only want to stock one spare. I kinda went on a tangent there. In your situation, I’d buy a 35/5 as a spare.

quote:

The Turbo 200 is best for people with multiple units and only want to stock one spare. I kinda went on a tangent there. In your situation, I’d buy a 35/5 as a spare.

Cool, thanks. That simplifies it for me.

Our AC went out on 5 July.
Had the AC guys out and it was a capacitor.
It would have been a free in-warranty fix except it was a holiday for them and they had to charge a trip charge only (free part).
Good thing but the cool bliss didn't last long because two days later the huricane hit and we we without power for 3.5 days.
It was painfully hot getting close to 90 inside but the rain kept it in the mid 80's.
No fun.

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~5 years is the average lifespan, and often less

Shhhhhhhhh

My upstairs 20 year old system will hear you

Ouch. Heat and humidity is a bad combo.

Out here, the heat is dry w/ relative humidity in the 20's.

I have solar - I'd really like to make it so that the solar could still provide power to the house during outages (at least during the day).

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Originally posted by konata88:
Ouch. Heat and humidity is a bad combo.

Out here, the heat is dry w/ relative humidity in the 20's.

I have solar - I'd really like to make it so that the solar could still provide power to the house during outages (at least during the day).

Isn’t that the whole point of having a solar system?

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Isn’t that the whole point of having a solar system?

You'd think. But that's not the way it was installed - some conformance thing with the utility company. Perhaps there is a way to make it work, similar to having some sort of transfer switch if one has a generator.

^^You need batteries if you want to decouple from the grid.

Oh yay!!

Fixed the AC. But now the power is out. Sweltering 90s again.

The voltage rating on a cap is not the big issue . Going from a 370v to a 440v cap does nothing for you . Replace the cap with an identical one as far as MFD goes . I ordered a spare cap and a contactor from Amazon and it has come in handy on a weekend when brother in law's unit crapped out .

https://www.youtube.com/watch?v=9OloCzaSPWE
Good info .

quote:

Originally posted by sigcrazy7:
If you want the best capacitor, you can buy an AmRad easily on Amazon. These are the gold standard, are made in the USA, but cost about twice as much as a Chinese one. There’s also Capcom (the old GE brand) that are made in Mexico.

Mars also offers Made in USA capacitors that run ~$30, though they do have a cheaper line that's made in Mexico that run ~$15.

Mars' made in USA ones have a 14XXX model number, while those made made in Mexico have a 12XXX model number. (For example, 14288 and 12288 are both 45/5 440 capacitors, just made in US vs. Mexico.)

Buy a couple of the size you need and keep them in stock. That's the first thing you replace when the unit stops working. Obviously, check the drain and make sure the float switch isn't turning the unit off as well.

quote:

Originally posted by tatortodd:

quote:

Originally posted by konata88:
Dumb question: If they didn't have my size in stock (35+5), can I use a different size, at least temporarily? Or is that very bad? Not sure which way would be okay - 40+5? 30+5? How much different would be okay if the one I need is not in stock?

I got lucky this time and bought the last one.

My coworker shared this with me, and it's what I keep on the shelf in my garage.

As previously posted, AmRad is made in the USA capacitors which for me prioritizes them above Chinese capacitors.

I could have bought the exact AmRad for my HVAC units but they were both replaced under warranty and I'm retiring in 3.5 to 5.5 years. AmRad Makes a Universal motor run capacitor that will work on my current units, would work on my neighbor's units (I would sell to them if theirs went out), and would work on the unit wherever I retire. It's more money but the flexibility was worth it for me. Link to AmRad Turbo 200 Universal Capacitor

Having an AmRad on the shelf paid off today. I have 2 HVAC units so I actually keep 2 on the shelf.

I came home from work and the master bedroom side of my house was 5 deg warmer than the other half of my house. I went outdoors to the compressor and the MBR unit is humming trying to start. I grabbed the capacitor out of my garage, a screwdriver, and a socket set. 15 minutes later, cold air is flowing again.