# Lennox Central AC Condenser Unit still trips 30 Amp Breaker after Cleaning Condeser and Evaperator?



## Don2222 (Aug 16, 2012)

Hello

Well now it is about time to get the bloody unit working!

I cleaned the Condeser Coils with the foam cleaner and hosed it off.
Also replaced starting capacitor and 30 amp panel breaker in main breaker panel inside house.
See detail and pics in link below.
https://www.hearth.com/talk/threads...r-buzzing-after-the-coil-cleaning-help.88931/

I cleaned the Evaporator A Coil with the Evaporator cleaner that does not need rinsing
Also vacuumed the return air filter and vacuumed out the Evaporator and fan housing.
See detail and pics in link below.
https://www.hearth.com/talk/threads...coil-cleaning-and-orientation-question.88982/

I also patched up duct leaks in the attic with foil tape!

The next step if to get a new Contactor!

*So here are my 3 questions to you AC experts? ? ?*

*1. Will a new contactor solve the problem of the 30 Amp breaker tripping?*
*If not is it a compressor going bad?*

*2. Will 5 more amps of contactor relay load capacity help?*

*3. Since the old contactor is a single pole does that mean there is a heater in the compressor that is powered on when the compressor is not running to warm the R22?*

The old one was single pole with 24 VAC coil
3100-150179

Voltage___FLA__LRA
240/277___25___150
______________________________________________________________________________
The new one I got is 2 pole 24 VAC coil and is better because it is more enclosed.
I only need one pole so If I hook up 1 pole and it wears out then I can use the other pole. It will last twice as long!
They did not have a 25 FLA so I got the 30 FLA with specs shown below:
Voltage___FLA___LRA
240/277___30____160

Pic 1 shows old contactor exposed coil - see yellow arrow
Pic 2 shows old contactor shunt - see yellow arrow

Pic 3 shows wires connected to the new contactor the same as the old contactor
However to use this double pole as a single pole the 2 black wires at the top were removed and pushed onto the bottom clips next to the black incoming hot lead. See Green Arrows in pic.

So I did change the black leads to the bottom terminals, then started up and AC is still running.
It has only been about 3-4 hours so far!


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## heat seeker (Aug 16, 2012)

I don't think replacing the contactor will solve your problem.

The load capacity only states how much current the contacts can handle.

Can't help you about the heater, although some units do have heaters in them.

It's possible that the breaker has been damaged due to the previous problems you had. Do you have another one you can swap in? Or can you measure the actual current being used in each leg?


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## woodgeek (Aug 17, 2012)

Not an expert but I tinker with mine a fair amount....

I agree with heatseeker....

How old is the unit??
I don't think an AC would have a heater....while a HP might.

A random thought....I was wondering if you had short cycled the compressor during your testing.  If you don't give the compressor at least 5 minutes after stopping before you restart, it can be potentially be damaged or have a harder time starting.  IOW, you would find that the compressor went to a 'buzzing' state, but then >5 minutes later it would start up fine.  On the same note, does your thermostat have a 5 minute cycle protection built-in (and activated)?


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## basod (Aug 17, 2012)

Larger crankcase compressors will have heaters in them - typically industrial units.
You need to ohm out both the compressor and fan leads to ground, during cleaning I've seen more than a few fan motors insulation compromised by getting the cleaner in the windings. Phase-phase short will pop a 30amp breaker.   Same could be true of the motor lead connections - check under the weather cover on the compressor for arcing(if it is removeable)
Disconnect the fan wires off the contactor and see if compressor runs without tripping breaker.  Then remove the compressor leads and reconnect fan leads, one or the other will trip it.  Just to be sure no other wires are grounded lift both of them and depress the contactor which would eliminate any issue with carbon tracking in the contactor being your issue.


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## begreen (Aug 19, 2012)

Replace the breaker and examine all connection for tightness including wirenut splices in between the panel and the unit. Also assert that the wire gauge is correct for the load and length of run.


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## Don2222 (Aug 20, 2012)

heat seeker said:


> I don't think replacing the contactor will solve your problem.
> 
> The load capacity only states how much current the contacts can handle.
> 
> ...


 
The current draw on each leg is 15 amps for the compressor and the fan. After the 30 amp breaker was replaced it started tripping more not less! After the contactor was replaced it did not trip much at all!

However I believe it still may trip on a very hot day!

So before I ohm out the Compressor we should try a "Hard Start Kit"  Why didn't someone mention this?
http://www.grainger.com/Grainger/SUPCO-Hard-Start-Kit-4E240


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## Don2222 (Aug 20, 2012)

woodgeek said:


> Not an expert but I tinker with mine a fair amount....
> 
> I agree with heatseeker....
> 
> ...


 
The T-Stat is an old round unit that has heating or cooling and worked fine for 10 years! You are correct, because the unit is about 10 years or more old it does not have a heater band around it. Still no sense in switching both legs if you do not have to.

So before I ohm out the Compressor we should try a "Hard Start Kit"  Noone mention this?
http://www.grainger.com/Grainger/SUPCO-Hard-Start-Kit-4E240

I still can bump up the breaker to 40 amps. However I will try the hard start kit first.


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## boosted3g (Aug 20, 2012)

A hard start kit is usually installed as a band aid or a hold over until the repair can be properly made.  Think of it as a super capacitor.  I replied in your other thread and I missed some info that was pertinant in other threads on the same topic.  If all this happened after a cleaning I would start with what was said at the beginning of this thread.


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## Don2222 (Aug 20, 2012)

boosted3g said:


> A hard start kit is usually installed as a band aid or a hold over until the repair can be properly made. Think of it as a super capacitor. I replied in your other thread and I missed some info that was pertinant in other threads on the same topic. If all this happened after a cleaning I would start with what was said at the beginning of this thread.


 
Hi boosted3g
It did not happen after cleaning.

The breaker started tripping, that is what caused this whole issue.

So we analyzed the system. We put the breaker back on after it tripped and measured the current of 15 amps in each leg. The FLA is 17 amps. It was running ok when we initially saw the system. The customer stated it kept tripping the breaker when it was hot out. The fan above the compressor was not blowing as much air as it should so I cleaning was clearly needed and should be the 1st step of the repair. So I cleaned the compressor coils and the next day, I also cleaned the evaporator A coil and changed the 30 amp breaker and 25/5 MFD capacitor on the outside condenser. It was tripping more with the new breaker so I changed the contactor and we got it running pretty well again. I think it still may trip in a real hot day so a "hard start kit" may be an inexpensive way to get it working the rest of the summer?
A new compressor is $1200 bucks min?


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## woodgeek (Aug 20, 2012)

My brand new HP had the occasional aborted start (noticed b/c it browned out my lights for a few seconds).  Never tripped a breaker, and resolved on its own on later cycles. (My house has a rather puny aerial line to the street, but the utility owns it, and says its aok).

I **think** the nominal starting amps on these things is close to 100A peak, and that most breakers are designed to ignore starting pulses.  I think all compressors have the occasional rough start.  I imagine as the units age those rough starts become more frequent?

I had a hard-start kit installed on my HP just to reduce the light flicker in my house.  It is not clear that it has done anything else for me.  The band-aid comment above sounds about right to me. FYI...there are third party starter kits out there on the intertubes that should be avoided.  Go with a manufacturer-listed part if you try this route.  IIRC three wire units are ok, two wires are junk??

Anyhoo...how do you know the tstat is not limiting the contactor switching current??  E.g. from oxidized contacts?


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## Don2222 (Aug 20, 2012)

woodgeek said:


> My brand new HP had the occasional aborted start (noticed b/c it browned out my lights for a few seconds). Never tripped a breaker, and resolved on its own on later cycles. (My house has a rather puny aerial line to the street, but the utility owns it, and says its aok).
> 
> I **think** the nominal starting amps on these things is close to 100A peak, and that most breakers are designed to ignore starting pulses. I think all compressors have the occasional rough start. I imagine as the units age those rough starts become more frequent?
> 
> ...


 
Hello

My heating man says he has seen alot of Hard start kits installed to prevent light dimming same as in your case. So it is not always just a band aid fix. They do have many more harder starts just before the compressor fails, but having a hard start kit is a good cushion to prevent your own power surging! Good to know they come in two and three wire kits. Thanks, I will check if I need one.

*Please tell me what is the Breaker Amperage that your AC is connected to?* My neighbor has a 30 amp and my AC man thought it should be 40 amp for this AC Compressor.

These hard start kits really save on your compressor wear!
http://www.amazon.com/Compressor-Saver-Hard-Start-Capacitor/dp/B003FNMADE

*Product Description*

Starting up is the hardest time in the life of any type of electrical equipment. Ever notice that light bulbs almost always burn out when you first turn them on and not while they are on? This is due to the huge current that rushes in when a switch is thrown and power is first applied. Your air conditioner uses anywhere from 5 to 10 times more power on start-up than it does while running. With this burst of power comes a surge of heat that accompanies the electrical current. This heat damages the compressor, the terminals, the windings and run capacitor - all vital components of your air conditioner. The 5-2-1 Compressor Saver® protects these components by significantly reducing the amount of time it takes for your compressor to start - in some cases up to 50%. This means your air conditioner and compressor will bear ½ the stress, strain and heat each and every time it starts. Considering that your air conditioner may start up more than 6,000 times in a single cooling season, the positive impact that the 5-2-1 Compressor Saver® has on your air conditioner is significant. Before you replace your air conditioner, try adding a 5-2-1 Compressor Saver®. The 5-2-1 Compressor Saver® might save you from having to outlay thousands of dollars to buy a new air conditioner or compressor. At a fraction of the cost, installing the 5-2-1 Compressor Saver® is a wise investment.


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## woodgeek (Aug 20, 2012)

My 4 ton HP unit pulls ~26A running, and wants a 40A breaker and wiring.  For the smaller system you are working on pulling 17 A IIRC, a 30A breaker seems like the right size.

The proper answer comes from the spec/install manual for the unit.  Does your high voltage wire correspond to 40 or 30A?


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## Don2222 (Aug 20, 2012)

woodgeek said:


> My 4 ton HP unit pulls ~26A running, and wants a 40A breaker and wiring. For the smaller system you are working on pulling 17 A IIRC, a 30A breaker seems like the right size.
> 
> The proper answer comes from the spec/install manual for the unit. Does your high voltage wire correspond to 40 or 30A?


 
Hi woodgeek

Many thanks for those numbers. I agree that 30 Amps is probably what was in the manual years ago and that is why a 30amp breaker was installed into the main panel for this unit. Not sure about the gauge of the wiring but if I get another peek I will check. The outside disconnect for easy servicing is a 60 amp breaker which of course never trips.


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## basod (Aug 23, 2012)

Don2222 said:


> Hi woodgeek
> 
> Many thanks for those numbers. I agree that 30 Amps is probably what was in the manual years ago and that is why a 30amp breaker was installed into the main panel for this unit. Not sure about the gauge of the wiring but if I get another peek I will check. The *outside disconnect for easy servicing is a 60 amp breaker* which of course never trips.


 
The outside disconnect is not a "breaker" it is a disconnect that is capabale of interupting the current rating if manually thrown.


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## Don2222 (Aug 23, 2012)

basod said:


> The outside disconnect is not a "breaker" it is a disconnect that is capabale of interupting the current rating if manually thrown.


 
Understood, but in this case to accomplish the disconnect, it looks like they used a 60 amp breaker.

See pic
Click to enlarge.
Says 60 on the bar that joins the 2 breakers


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## heat seeker (Aug 23, 2012)

Around here, that's not done - putting a breaker outside, even in a watertight box. They use a simple disconnect where you pull a piece out that breaks the circuit. It's just for the serviceman's safety.


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## seige101 (Aug 24, 2012)

The better question is why there is a 240 volt outlet off the side of the disconnect, especially without a weather proof cover on it.


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## heat seeker (Aug 24, 2012)

seige101 said:


> The better question is why there is a 240 volt outlet off the side of the disconnect, especially without a weather proof cover on it.


 
Good point! This electrical work is beginning to look suspect.


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## woodgeek (Aug 24, 2012)

My codes require a 120V 'convenience' outlet be installed near the condenser.  Is it really a 240V outlet, or a 120 wired to a separate circuit?


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## SmokeyTheBear (Aug 24, 2012)

seige101 said:


> The better question is why there is a 240 volt outlet off the side of the disconnect, especially without a weather proof cover on it.


 

It appears the hand is holding open the outlet cover.


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## Don2222 (Aug 24, 2012)

SmokeyTheBea
r said:


> It appears the hand is holding open the outlet cover.


Correct Smokey it is a weather proof cover I am holding up. How ever the outlet is 240v on the same circuit! I tested it with my DVM!


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## SmokeyTheBear (Aug 24, 2012)

Don,

Have you tried redoing all of the wire connections removing any oxidation and providing a bit of protective conductive coating?

What is the HP of the compressor and does it and the fan motors start at the same time?


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## ROVERT (Aug 24, 2012)

I strongly suspect that someone (probably a homeowner) wired that receptacle on there to be used as the feed off of a back up generator. Probably not how I would do it, but I don't see why it wouldn't work. I've seen a number of disconnects with breakers for condensing units. Pull-out disconnects are definitely more widely used. I'm not sure why that one has a 60A breaker. Someone probably just had it lying around and decided to put it to use. It doesn't really matter as long as the breaker in the main panel is a 30 A and the wire is 10 ga or larger. 

As to the air conditioner, you can try throwing a hard start capacitor at it, but I suspect the compressor is in the throes of death.

You should not put a 40 A breaker in the main panel unless that is what is listed on the unit. If the unit does allow for a 40 A breaker you need to make sure that the wiring is adequate. I really don't think this is the problem though. Except for a bad connection somewhere, I think you're looking at a compressor problem. The unit obviously ran for a number of years on a 30A breaker, there is no reason to think that upping the breaker size now is a way to fix it.


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## Don2222 (Aug 24, 2012)

SmokeyTheBear said:


> Don,
> 
> Have you tried redoing all of the wire connections removing any oxidation and providing a bit of protective conductive coating?
> 
> What is the HP of the compressor and does it and the fan motors start at the same time?


 
Hi Smokey

It was working fine for about a week, now the compressor is making some nasty noises.
*Does anyone know if the compressor can be fixed for a low price? *

*All the Central AC techs in this area do not want to mess with an older R22 system. They all want from 3 - 5k to replace the compressor and evaporator and use the newer freon!*


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## velvetfoot (Aug 24, 2012)

Can you buy a replacement heat pump that's good in cold weather? 
It could at least take care of the shoulder seasons, maybe cheaper than pellets.
How about something like this?:
http://www.carriergreenspeed.com/


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## ROVERT (Aug 24, 2012)

Don2222 said:


> Hi Smokey
> 
> It was working fine for about a week, now the compressor is making some nasty noises.
> *Does anyone know if the compressor can be fixed for a low price? *
> ...


 
To answer the first question, not really. Unless you have your EPA cert., a reclaimer, refrigeration scales, a gauge set, vacuum pump, brazing tools/supplies, a cylinder of R-22, and a little bit of know how your going to have to pay somebody with all of those things to do it. There is a considerable amount of time, skill, and equipment involved in swapping out a compressor and you're going to have to pay for it.

The reason nobody wants to replace the compressor is not because they don't want to mess with R-22, it is because it is a repair that doesn't typically make sense. There's too much labor involved to replace a part on a 10+ year old system that will likely encounter more problems not so far down the road. FWIW, if you find someone to do the compressor replacement, you'll be looking at a bare minimum of a $1000 and quite likely somewhere between $1200 and $1800, maybe more. If a new system can be had for $3000 (which I doubt) that would be the way to go. $5000 sounds a little closer to reality.


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## ROVERT (Aug 24, 2012)

velvetfoot said:


> Can you buy a replacement heat pump that's good in cold weather?
> It could at least take care of the shoulder seasons, maybe cheaper than pellets.
> How about something like this?:
> http://www.carriergreenspeed.com/


 
If this is an AC only unit (not a coil on top of a furnace) the ductwork is likely only set up for AC. Installing a heat pump with only ceiling returns (probably only one ceiling return) is kind of a waste of money. The air is not going to circulate properly. For a heat pump you need high/low returns, ideally in every room (except kitchens and bathrooms). The high returns bring the hot air back to the system in cooling mode and the low returns bring the cold air back to the system in heating mode.

If this is a coil on top of a furnace and there is proper ductwork, a heat pump may be worth considering. It depends on what the primary heat source is and the climate. With natural gas heat, a heat pump doesn't really make sense. If it's oil, propane, or electric a heat pump may be a good idea.


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## blades (Aug 26, 2012)

Have you had the amount of freon in the unit checked? If it has an extremely small leak over time so that the feon level is quite low it could cause this these symptoms. Especially if most other things are checking ok. I replaced my AC system 3 years ago as this was the case of the unit, It was down to about 1/2 lb, still operating, but current consumption was off the charts ( I had installed that unit in 1972, i do not expect to see more than 10 years out of the current crop of equipment) One other area that I did not see mentioned in either thread is a bad ground/ neutral, not necessarily in your homes wiring but from the main line house connection to the pole transformer supplying your home. This is a somewhat rare problem but does exist and getting your utility to check/repair is a pia ( got the t-shirt). creates all sorts of weird problems, but breakers popping on startups for no apparent reason is a classic.


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