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Help with CH240 breaker

Posted by jeanie_beth (My Page) on
Tue, Jun 29, 10 at 10:12

My central A/C unit is on a CH240 breaker--it controls the compressor/ thing that sits outside of the house with the fan motor.

Sometimes like during a storm and the lights blink off, the breaker will trip off--the fan keeps running on the A/C inside but the compressor is not on...then I have to trip the breaker back on.

The other day, I came in and it was hot inside, so I figured the breaker must have tripped..I looked at it and it was still ON, so I called the repairman.

He came out and took about 2 minutes and said all was fine--the breaker had tripped...he charged me $150.00.

I told him the breaker was showing to be ON and not tripped...he told me that you have to sometimes flip them OFF & ON several times.

Is this true?

Keep in mind that here in TX now we are having extremely HOT temps and the A/C unit can't keep up with the heat.

Anyway, this breaker feels very warm to the touch...sometimes the A/C seems like it is not working in midday so I go up and feel of the breaker--it is warm and I trip it OFF manually, then when I trip it back ON, it kicks OFF immediately...so I wait a few minutes and turn it back on and all is fine...the compressor seems to kick in then.

This breaker is at least 15 years old--do I need to change it out?

Is it true you sometimes have breakers that are tripped yet do NOT appear to be in OFF position and you have to flip them a few times?


Follow-Up Postings:

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RE: Help with CH240 breaker

A double breaker can be tripped and still show ON.

You should NEVER turn off the AC breaker then immediately turn it back on. If you turn it off, you must leave it off for at least 2 minutes before attempting to turn it back on again. Not doing so can be an expensive error since it could damage the compressor severely.


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RE: Help with CH240 breaker

Yes, a lot of breakers will trip without moving the handle all the way or much at all.

When you turned off the compressor the pressure built up in the cooling unit and locks the compressor for a few minutes until the system balances itself. The breaker has nothing to do with this except for tripping because the load is too heavy for a few minutes.

Maybe you need a new cooling unit that won't trip the breaker by putting too large a load on it.

We have window units and I know that if I turn it off and then on immediately the compressor will try to start for a few minutes until it actually catches without tripping the breaker. Your outside unit should do the same IMO.


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RE: Help with CH240

Typing while weedmeister was answering.

Good advice but I don't buy the serious damage part. We have had window units and outside compressors that go off with a momentary power glitch and never get hurt. And not just once either.


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RE: Help with CH240 breaker

If the breaker enclosure is in direct sunlight, the heat may be contributing to the tripping of the breaker.


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RE: Help with CH240 breaker

"Good advice but I don't buy the serious damage part. We have had window units and outside compressors that go off with a momentary power glitch and never get hurt. And not just once either."

All you need is for th ecompressor to have stopped almost at the top of its compression stroke and then be turned on before the gas leaks back into the system.

The induction motor in the hermetic compressor may not have enough starting torque to overcome the load placed on it.

The thermal overload should trip before the compressor motor is damaged, but every time you allow that thermal overload to operate the motor windings have been subjected to higher then normal heat.

Many breakers do not move anywhere near the off position when tripped.
Th handle is actually disconnected from the internal mechanism when it trips (this prevent the handle holding the contacts closed under an overload).

You need to move the breaker fully to the off position (in many you can feel the springs used to 'trip' the breaker being compressed) and than back to the on position.

Until placed firmly in the off position, the handle is not actually connected to the contacts in the breaker.


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RE: Help with CH240 breaker

Thanks guys for the info. Today was an unusual day for this breaker. I came in and once again, it was hot, so I went up to the breaker box and the CH240 breaker was indeed fully tripped OFF and the compressor was not on. I tripped the breaker back to ON and compressor comes on and runs just long enough for me to get to bottom of stairway and it trips OFF again.

I called repairman again--they come out and tell me it is "start up capacitor" or either the fan motor. They removed the covering on the fan motor and capacitor. They said the capacitor was burnt up.

They replace capacitor. I hear them when they kick the breaker back to ON, the lights flickered and heard one of them scream to other guy to kick it off...I heard a "metal to metal" noise.

I go up there and they said the FAN BLADE broke off and that the fan motor was fine--only the blade broke.

They said it wasn't their fault...also said it would be hard to find the correct fan blade...they said they'd be back..finally just about an hour ago, they came back with a fan blade.

They had tools laying everywhere at first--I really think they may have left a tool inside the unit when they initially kicked it back on and the fan blade hit it and broke--can't prove it though.

Anyway, the unit is now cooling as best it can in this TX heat.

I know I need a bigger tonnage unit to handle the heat so as to prevent overloading and heating up the breaker.

They also put me a new CH240 breaker in today..but it gets hot too.

They said it wasn't really a fire hazard--just that it was "over amping".

I kind of wish the compressor would burn up so that landlord would replace the entire system as it is over 22 years old...I wouldn't even care if he went up on my shop rent!

I'm sure the compressor won't burn out though until day after I sign the line to purchase the shop building from the landlord!

They replace the capacitor


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