Question about Fujitsu 18C1 Air Conditioner

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I turn on the unit and in about 1 .5 min it trips the cb ,, I put a amp probe on the circuit and found out that after 1.5 the unit jumps up to 40 amps on a 15 amp breacker which the unit is rated for . the unit never actually runs ,, it just trips the cb

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Firstly was the unit working previously on the same circuit? , if yes most likely there is a problem with the compressor(pot)this can be the compressor seized or winding shorted, It can also be the Capacitor for compressor faulty, It is worth replacing the capacitor with the same type and you may get lucky if not a new compressor is required,
Good luck

Posted on Jan 22, 2009

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You are going to have to install a disconnect box next to the unit, with the proper sized fused disconnect inside, and have a new breaker installed at the panel, when the unit comes on, its the compressor that takes the most energy to run, the compressor at start up draws alot of amps, You will need to talk to an Electrician to do your breaker and disconnect work,

Posted on Jan 20, 2009

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My heater is one year old but this year every time I plug it in it trips the fuse after running for approximately 30 - 40 mins.

Sorry to read about your problem, I hope this helps you out.
I will assume, your heater is around 1100 to 1500 watts. For example if it is 1500 watts, you cant really share the heater with a TV or stereo on the same circuit.

Feel the cord, and if it feels have to much on the circuit...If you live in a real old home, they where not made to handle the big of a heater.

and it may take 30 to 40 min to trip the fuse

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Dec 27, 2010 | Heating & Cooling

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OUr air conditioning system works well until the circuit breaker trips. We added another large return vent in the hall to try to get more air circulating and that didn't work. We just replaced the...

Current (amps) is voltage (volts) divided by resistance (ohms) or I=v/r. Breakers "trip" when there is too much current flowing through them. This can be caused by wiring that is too small for the application or a short (or a bad breaker, but since you just replaced that).

Cable Size:
The conductors have resistance and heat up when current runs through them. Properly sized conductors allow this heat to be dissipated. Long cable runs or cable runs which are tightly bundled with other cables can prevent this dissipation. Heat adds additional resistance which in turns causes more heat, eventually tripping the breaker to prevent a fire. For a 40 amp breaker, the cable should be a dedicated, 8 gauge wire.

A short (low impedance connection) can be between two conductors or between one conductor and ground (also called a ground fault). Shorts can be tough to track down when they are intermittent. This can be because the insulation was damaged (during installation, by rodents, etc). Moisture can deteriorate insulation or conductors.

It may only be present under certain conditions, so you can try this immediately following a trip. Shut both the breaker and the cutoff at the condenser (you want to isolate the cable), then use a meter to check for bleed between each of the conductors and each other conductor or ground. The neutral eventually connects to ground so it will have zero impedance. If you find there is a connection, you (or your electrician if you don't know what you're doing) will have to track it down and repair it.

It could be a clamp that is too tight where the line enters a jbox or panel, a staple that was driven too far and is biting into the insulation, a bend that is too tight, or a length that isn't supported well and subjected to vibration from a nearby motor .

Other possibilities:
At 40 Amps they'd be really expensive, but are you using a GFI or Arc-Fault breaker? Either of those could cause unwanted tripping.

Good luck with it.
jack g

Aug 06, 2010 | Heating & Cooling

2 Answers

Thermostat inside went up to 78 degrees which was set for 73 degrees. I checked filter filter was clogged. I cleaned filter. However could not get outside unit fan to go on even after turning off for 20...

Did the circuit breaker trip or did you turn it off and back on? If you had to remove the blower door to get
to the filter make sure the door is secured because
the door has a rocker switch that powers the entire unit.

Jun 17, 2010 | Heating & Cooling

1 Answer

Single Split Wall Type Air Con Blows 15A CB as External Fan starts. Short in Fanmotor or Cap?

what size a/c ? will assume under 10,000 btu if cb blows on fan only and fan not turning assume fan problem caps will let fan hum like trying to start but a 15a seems low for a window unit also anything else on circuit best way to determine is use an amp probe to see how many amps are being drawn if amps peg meter on start a winding or short in motor

Oct 07, 2009 | Heating & Cooling

1 Answer



Aug 10, 2009 | Weather King 10AJA6001AH Air Conditioner

1 Answer

Air conditioner trips circuit only in the evening?

first off, it's illegal to release freon into the atmosphere. the epa could charge you $32,500, so keep it under your hat. second, if it's getting too cold where the evaporator coils are icing up, it's too lille freon, not too much. as for the breaker tripping, your compressor might be wearing out. if it's pulling too much current, the motor is failing and the compressor needs replacing. and do not do it yourself unless you're certified by the epa to move freon and have the proper equipment to recollect the used freon.

Jul 29, 2009 | Heating & Cooling

1 Answer

I have a 220v 100 amp circuit breaker that feeds a sub-panel. The sub-panel has 3 circuits: a)60 amp Heater (unit 1 in house) b)60 amp A/C (unit 2 in house) c) 40 amp for pool equipment. The 100 amp...

your a/c uses the blower motor from the heater to distribute air check for loose wire connections that will raise amperage and also make sure you have the right size wire to each unit 40 amp should have 8 awg(copper) wire and 60 shouldbe 6 awg i think if the wire is to small=heat= higher amperage

Jul 14, 2009 | Heating & Cooling

1 Answer

Breaker trips on roof top RV A/C

check your breaker is it hot to the touch?
check the wire tightness at the breaker?
remove the circuit breaker and inspect the terminals on the breaker and in the panel and the breaker itself for signs of overheating and discoloration due to the fact
check the connections at the unit itself
check that you have proper voltage to your unit
find the nameplate and look for FLA full load amp draw
is the breaker properly sized for the unit and is the wire size correct for the breaker?
(Check nameplate on unit)
buy a clamp on amp meter and see if it is under or over the nameplate rating when unit is running
take great care when you venture into electric,if you arent comfortable find someone who is.
you may have a weak breaker if all the above pass?
Replace it

Jul 05, 2009 | Dometic Rooftop RV Air Conditioner

1 Answer

Cooling system trips breaker

looks like you have a problem on you're compressor circuit.

I'm assuming that this is a pretty small unit...On you're circuit you should have a start relay/overload located on the compressor connection itself and a capacitor.

To troubleshoot this you will need a multimeter set on ohm, to check resistance from the compressor to ground.

Once you have pull the plastic relay from the compressor (power should be disconnected by now!) You will exposed 3 connectors on the compressor. Put 1 probe on the compressor casing and move the other probe to the 3 connectors on the comp. If you have any resistance (if you ear a beep) you have a grounded compressor and that's that, might as well give up now and get yourself a new one.

I can tell you how to check the capacitor and the relay if the compressor check out OK. my name is Benge (nick name Benge007)

Let me know, I'm knew at Fixya, I'm just doing this for fun, free

May 26, 2009 | Heating & Cooling

2 Answers

Electrical - Air Conditioning

Ben, you are on the right track. To upgrade the breaker, first look at the main house breaker panel and determine if allowing more current through main breaker will be taxing it too highly (will 20 more amps exceed my main breaker limit...what is the main breaker current trip at?) Then look at the wire size leading away from the 40 amp breaker to outside. If it is 6 gage copper or 4 gage copper-clad aluminum wire, you are ok to upgrade. Any smaller wire size could be unhealthy.

Sep 03, 2007 | Heating & Cooling

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