Cold air then no cold air: High side too much pressure?


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Old 07-05-06, 05:07 PM
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Cold air then no cold air: High side too much pressure?

I must say, a very informative forum and I have learned more about AC's in the last 2 days than the repairs guys could ever tell me.

I have a 1992 Carrier central AC which will cool off the condo at night, but durning the day time it will either not put out cool air or cuts out in 10 min or so.

I am having this fixed professionaly, but 3 guys so far can't come to the same conclusion.

There is no shortage of freon, but the whole unit itself was very dirty since I live about 300 yards from a massive scrap yard that produces tons of dust.

I just moved in, but I had the the unit cleaned professionaly. The high side pressure (I think its pressure) was 350 before cleaning and now its at 290.

One guy says the air coming off the top of the AC feels really hot and does not think the fan is spinning fast enough to cool the compressor and therefore it trips off when it gets too hot.

Although the fan outside continues to run when there is no longer cold air from the ducts.

I am having the fan changed this week, but from what I describe, do you believe this will solve the issue or might there be other things I should question these people about when they come out?

Thanks in advance for your help
 
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Old 07-05-06, 05:35 PM
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High side pressure

If your condenser was that dirty, I hope they used coil cleaner & rinsed it well from the inside out. Sometimes condensers need cleaning more than once to get all the crud out. I prefer the cleaners which foam heavily.
 
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Old 07-05-06, 08:50 PM
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Usually the high pressure switch opens the contacter. The fan wouldn't run too. Check compresser amp draw. And when compresser shuts off check the overload and cap.
 
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Old 07-05-06, 09:27 PM
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Im with Grady.
There is no shortage of freon, but the whole unit itself was very dirty since I live about 300 yards from a massive scrap yard that produces tons of dust.
Are you sure the condenser is clean. Around here even when we have oak pollen in the air. We have to go back sometimes and clean the condenser on units.

"There is no shortage of freon". I have ran into units like yours. Where some one over charge it trying to get it to cool. Then turned a hose to spray on it a little to keep the head down. the more we cleaned the outside coil and the inside coil . We had to keep takening freon out of the system.
The things we run into. Ill bet a 1/4 of the time all we do is clean the AC units.

ED
 
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Old 07-06-06, 08:13 AM
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Hmm, so maybe this fan is a waste of money?


When the guy cleaned it, he did use this pink soap stuff and it was foamy. I am not sure how well he cleaned the inside because I do not think he took off the top fan portion to spray the internal parts.

I'll keep you posted as things come around, but this has been a slow process. I guess high demand for these guys this time of the year.

And you know what, I tested the AC in the spring to try and avoid this, but I guess it wasn't hot enough yet to cause this problem.

Oh well, lesson learned.
 
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Old 07-06-06, 11:47 AM
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Without the proper equipment you cannot determine if the fan is turning fast enough or not. I have seen techs reverse the wires on the capacitor to turn the fan in the opposite direction and when that is done the fan turns at about half speed. When your guy comes to check the fan make sure he inspects the fan and fan motor for proper connection and rotation before he just blindly changes it.

I'm with everyone else here. Make sure the coil is clean throughout. Many times the outside looks clean but it is just because the outside dirt and grime is now mud that is packed deep into the fins and hardened into a complete blockage (although the pressures do not suggest that yet.)
 
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Old 07-06-06, 05:51 PM
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Condenser cleaning

Without flushing from the inside out, especially if yours is a double thick coil, usually all of the crud (highly technical term ) does not get removed.
 
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Old 07-06-06, 08:59 PM
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Ok, so I just went out to the AC and looked at it in and out. It does seem clean now except for a little rust on the big black box in the middle (condensor/compressor?)

The coil is single. I just took a flashlight to it and can see through the tiny little fins (they project 360 degrees). Although I do see at the very tip of these fins (last 30%) some oxidation. I know these are there to increase surface area, can this oxidation cause problems?

We'll see what this $590 dollar install will do. Motor/blade/labor/tax
 
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Old 07-16-06, 02:19 PM
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Well the guy charged me $700 for the fan and labor. Such a rip off. He said the secertary miss quoted me

So he changed the fan, capacitor, fan blade and the damn compressor still kicks off when its hot outside.

I looked inside the AC unit and he did do a good cleaning job before. No dirt or pollen in sight or on touch.

He now says the compressor valves inside could be bad or something else with the compressor.

He suggests, since the unit is 14 years old, to change the whole thing while there are still some 2 ton 10 SEER's on the market

Would you all go as far as changing the whole unit?

Its going to be hard to find the cash to replace it after I just dumped $1000 into this thing and its still broken
 

Last edited by brocnizer; 07-16-06 at 02:34 PM.
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Old 07-16-06, 04:45 PM
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Compressor valves

Most of the Carrier units have service valves. If yours does, any decent servicer can check the valves by doing a "pump down". This only takes a couple of minutes & does not require any kind of "special" tools. Has any one measured superheat, subcooling, & amp draw? In addition to motors turning the wrong direction, I've seen fan blades installed upside down.
 
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Old 07-16-06, 07:13 PM
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Did he clean the inside coil. How can the compressor be bad if it pumps to high a head???
Have they checked the TXV valve if you have one or the orifice if you have that. This is at the inside coil

ED
 
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Old 07-17-06, 07:25 AM
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I mentioned "do you think there is a problem with the expansion valve?" and the guy just said "no" without looking at it.

I'm going to look for a 4th repair guy. I haven't had much luck. No one seems to be doing what you all suggest...all they want to do is replace parts blindly and hopefully it solves the problem.

Too bad you all don't live around here, I'd hire ya in a heart beat
 
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Old 07-19-06, 02:11 PM
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Thank you all for your help. The problem, after 3 weeks, has finally been found.

I called a Carreir Authorized dealer and they came out. They spent 1.5 hours going over the whole system. The other $hit heads spent 10 min and 15 min respectivily trying to diagnose the problem.

Although, the Carrier guy was stummped at one point and I said "how about a pump down?" He said "yeah man, great call"

Anyways, pump down proved the compressor to be bad.

$1900 for a 2 ton York-Coleman with install....sound good?

Spent $1000 diagnosing the problem, its not fixed, yet only another $900 would have got me a new unit...strange

I hope this thread will help others in the future.
 
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Old 07-19-06, 06:05 PM
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York/Coleman

I have no problem with the equipment but would like to know: SEER rating, indoor coil?, new lines? The $1900 sounds a bit high but not knowing the installation details or labor rates in your area, it's hard to say if that's a fair price or not.

Suggestion: Since the Carrier guy seems to know what he's doing, why not as them for a quote?
 
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Old 07-19-06, 07:45 PM
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10 seer and the lines stay the same since the way they built this place it is impossible to reach the lines (in a condo). The Carrier man said if the lines every go I am really screwed. No way to really change them out.

The Carrier people also gave me a quote: install a Goodman for $1900. I will go with them. I know this is not the best unit, but I plan to leave this area in 2 years so let the next guy worry about it.

This price includes the outside unit, charge it up, dispose of old unit.

NJ is a money sucking state in every respect and I can't wait to leave this hell hole. Labor rates for everything in this state are top dollar, just because we are taxed to hell and it all gets passed down to the consumer in some way.
 
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Old 07-19-06, 07:55 PM
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N.J. Prices

Hey, it could be worse. You could be in Taxachusetts. I know things are bad in Jersey. My neck of the woods is full of N.J. refugees.
Like I've said dozens of times before, there is nothing wrong with Goodman equipment as long as it is installed right. Mine is 15 years old & since I installed it I've done nothing except change the filters & wash out the outdoor unit. Good Luck with your new system.
 
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Old 07-19-06, 07:57 PM
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Originally Posted by brocnizer
The Carrier people also gave me a quote: install a Goodman for $1900. I will go with them. I know this is not the best unit, but I plan to leave this area in 2 years so let the next guy worry about it.
I think that's a little high for a 2 ton Goodman condensor swap but if installed properly you should be ok.



Originally Posted by brocnizer
NJ is a money sucking state in every respect and I can't wait to leave this hell hole. Labor rates for everything in this state are top dollar, just because we are taxed to hell and it all gets passed down to the consumer in some way.
Hey but you have full service gas stations. Good luck
 
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Old 07-19-06, 09:08 PM
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Im with the rest of the guys here. For what you pay the tech's up there they should have to go back to school.
That bad compressor should have showed up when they had the gauges on it the first time . If they had turned the unit off and on a few times. Also on some you can hear the blow back when you turn it off. Or just put your hand on the suction line when you shut it off It gets hot from the blow back when you have a reed or valve out.

ED
 
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Old 07-20-06, 06:45 AM
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Well, lesson learned and unfortunatly its the mom and pop AC company that is going to get hurt with my experience.

I will never hire the small operation guys again in my life. I will only go for the huge ones like these people I have now. I think they have like 90+ employee's.

Sigh

Again, thank you all for the help
 

Last edited by brocnizer; 07-20-06 at 06:55 AM.
 

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