ReplyIt'll run but the amp draw will be too high. They're getting maybe 4 SEER out of it.Originally Posted by timjimbob
Professional Member*
Came accross a very old Singer comfortmaker AC yesterday. Everything was butchered on this.
Found wire connection on comp cap burnt off. Could not find matching burnt wire, The more I studied this, there is no run cap in this circuit, only a hard start kit........and it runs and starts fine.
Verified, no amp draw through only wire to cap or start terminal at compressor. Draws about 23amp on line 1. Cannot verify compressor info, no name plate is removed.
Professional Member*
It'll run but the amp draw will be too high. They're getting maybe 4 SEER out of it.
Professional Member*
Amazing that it restarts pretty easily.
Professional Member
If it has a start kit it will start. It won't run very efficiently though. Throw a 35 cap on there, it will be better than nothing. If you really want to get the right cap, try a bunch of different ones and use the one that gives the lowest amp draw on C of the compressor.
Regular Guest
Seriously man? I hope that was a joke.
Lets do this the correct way. 2652 x Amps / Voltage across cap ='s required cap size. It can be done in under 30 seconds. When you guys have one of those cap's that looks like it had been in the ocean and can't read the #'s, use that formula. Will work every time. You get your amps to plug in the formula off your start wire (herm) coming off cap. Your voltage comes from (c) and (herm).
Professional Member*
Uh...I believe this formula is for determining what a cap is actually measuring under load - not what it's supposed to be...
Is the Religious Right to blame for Christianity's decline?
They argued that, as the Religious Right became increasingly visible and militant, it became associated with Christianity itself. And if being a Christian meant being associated with the likes of Jerry Falwell, many people—especially political moderates and liberals—decided to simply stop identifying as Christians altogether.
http://www.theamericanconservative.c...nitys-decline/
Professional Member
Correct
Regular Guest
Dang, yes this formula does determine the correct size of the field capacitor.
Professional Member
The link has more info than that, says it isn't reliable to calculate "needed" uf..
Professional Member*
Negative. It does not determine the correct size needed. It merely determines what the installed cap is actually delivering.
Is the Religious Right to blame for Christianity's decline?
They argued that, as the Religious Right became increasingly visible and militant, it became associated with Christianity itself. And if being a Christian meant being associated with the likes of Jerry Falwell, many people—especially political moderates and liberals—decided to simply stop identifying as Christians altogether.
http://www.theamericanconservative.c...nitys-decline/
God Speed, Jim. We'll miss you - 2-26-23
No, it only tells you the capacitor's uF under load. Not what size capacitor to use.
Professional Member*
This way should work when you have no way of getting model numbers. Is there a tag on cabinet saying total amps ?
Global Moderator
I would suggest you try this experiment on your next service call:
Test a known good, properly sized capacitor, (say a 40 mfd) with the formula, then replace the capacitor with a known good capacitor that is 10 mfd lower (a 30 mfd). Re-run the test, and see what your results show.
Then come back on here and explain what you found.
Instead of learning the tricks of the trade, learn the trade.
kdean1 liked this post.
Professional Member
I guess the test was never performed
Regular Guest
Doing that on my 4 ton ac tomorrow. Lets find out together.
Professional Member*
Sometimes it's more expedient to just take someone else's word for something, especially when there are several someone elses saying exactly the same thing. A large number of people in agreement doesn't mean that they're correct, but in this case they are indeed correct.
I apply the capacitance formula almost on a daily basis. You measure the voltage across the capacitor terminals, and then the amperage of the start lead coming off of the capacitor. The actual capacitance of the capacitor is then
2653 x start amps/ capacitor voltage
This only works on sinusoidal 60 hz power sources BTW. You can plug the capacitor directly into a wall outlet and use this formula to determine the capacitance value. Somebody tell me, "what size capacitor is the wall outlet supposed to have connected to it?" If that question doesn't make sense, reread the thread.
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