My 36 year old 3 ton Lennox AC outside started making noise on start up.

NickD

wrench
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Circuit diagram was on the inside electrical panel. This was on a brand new home due to a job change my forth home, the first three I installed myself.

Lost all the R22 after the first year, Joe Weak tightened all the fittings, but under warranty, so they filled it, I watch them with their pressure gauge. I tightened all the fittings, haven't lost a drop of R-22 since.

I pulled the run capacitor to test it out, 5ufd for the fan motor and 40ufd for the compressor, for whatever the reason, the fan and compressor wires were reversed, so why not problems after 35 years,

Made in the USA by GE the 5ufd checked out perfect with my capacitor bridge circuit, but the 40ufd read at 37, no leakage, but close enough.

Trying to find a replacement is out of the question, all I could find was crap made in China. But can't explain after 35 year years, never had start up noise, the capacitor gives the second phase a 90 degree lead. Is continuous, other capacitors are switch out with a centrifugal switch. These have dirty switch contact problems. Anyway, finally making it right cured the start up noise.

I am cooling 4,000 square feet, have plenty of tall trees around the home, talk about global warming bullchit, my AC bill for last August, the hotest month of the year, my electric bill only increased by 5 bucks.
 

nickb2

Wrench. Diagnostic Tech.
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Nickd, can you recommend a good cap tester that I may find used on line in a "lets say north american made" variant.

I know I have to invest in a cap tester, one for the ev cars, so I wanted to know what you use to check your farads.
 

billr

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If you have a decent scope, checking C or L is fairly easy. It is more cumbersome than a dedicated tester, but is the practical way for poor-little-me without unlimited funds for equipment.

I have been doing a lot of research and experimentation lately pertaining to motor drives (my EV bug); Three-phase stuff cries for a 6-channel scope, but I only have four!
 

NickD

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While I have professional capacitor testers only good for small capacitors. a 370 VAC 40 ufd capacitor is not small and is also bipolar.

Formulae is simple, T=RC for a capacitor to charge up to 63% if the the applied voltage so can use say a 200 volt power supply and a stop watch, for a 40 ufd capacitor or 0.000040 f with a 1 Mohm resistor in series, should take 40 seconds to charge up to 0.63 X 200 or 126 volts. Can also work this backwards. With a metered power supply can measure the leakage current. A current inductive meter is better for this.

With an AC capacitor, tested twice second time with reverse polarity. If it charges in say 30 seconds to this value of 126 volts, its only 30/40 times 40ufd its only a 30 ufd. If it doesn't charge at all and this happens, the capacitor is shorted.

Use to work these equations in my head, but electronic calculators made me stupid as is all these new safety stuff on new vehicles.
 

NickD

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Was also low on charge and had some R22 hidden away, when I hit the low side pressure with a charge, the high side pressure was low showing leakage in the piston rings in the compressor, So elected to buy a new one. Now I see they are all R410A claim doesn't contain any chlorine like R22 that only contained 1/100th the value of Chlorine in R12 that never was proved to harm the ozone layer even by NASA, Al Gore is a liar and should be put in jail, but greedy corporations making a hell of a lot more money with R410a went along with it.

Can't fight city hall, so just pay through the nose, bend over and smile. Son purchased a new home 10 years ago with an AC made in China, I found leaks all over the place, but with the help of his dad made the builder install a brand new unit made in the USA. China and all of South America is still using CFC/s. But Canada that hardly needs AC banned all CFC's believing crooked Gore.

Trying to convince idiots and its working the C02 that only occupies 0.04% of the atmosphere, only resonate to an extremely wavelength of the sun and only when the sun is out, black on the south pole for six months out of the year and our vegetation requires this gas for survival is causing global warming. When the real culprit is the sun, not thermostatically control and an earth 75% covered with high specific heat water and land with 100% relative humidity.

Worse thing are idiots in beleiving in this BS and the world has no shortage of these. R22 was 2$.02 a pound.
 
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