Air trapped in the system


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Old 07-28-07, 10:07 AM
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Air trapped in the system

I have a new carrier model 24ACA system w/ r-407(2 months old). Last night it appeared my coil froze up ( unit was running and supply air temp was in the 80s) Washington DC weather last night was hot, humid, w/ periods of rain.

I shut the system down for about 30 minutes - replaced the existing filter (20 days old) with a new filter and started the system back up. Cooling was restored.

I spoke with the installing contractor this morning and they decided to send a tech out to investigate. After his initial check of the system the tech is concerned that there is air trapped inside the system and recommended I call again on Monday to schedule another service call. He was purging the system and felt he did get some air out but thought it would be best to schedule the service.

How does air get trapped in the system? During initial installation? Does this effect my warranty with Carrier? Any negative side effects that
could also appear as a result?

Thanks,
Matt
 
  #2  
Old 07-28-07, 10:45 AM
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You can call it air . But what it sounds like is you have contaminate's in the system . They can be moisture and air as noncondensables. Id say they didnt do a good job when they vaccum the system. Could be did they use old lines with the R410a and didnt clean them right? If this is what is wrong with your system. Dont in anyway let them put the old R410a that is in there now back in it . You want all new R410a
2 months Id say first you might also have a leak there. If so have them find it for sure. Again if so make sure that they put all new R410a in it.

The company has to back it and Id say its their fault. Id keep all paper work on the call backs you have had.
 
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Old 07-28-07, 11:07 AM
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How did he "purge" your system of air?

A frozen coil is usually the result of a low system chrage. Noncondensibles (air) in your system will actually cause higher operating pressures, sludge-acid build up and inefficient operatiing conditions, and eventually compressor failure.

Purging "some" of the air from a system, in all honesty, is ridiculous and it sounds like the people you're dealing with don't know what they're doing.

Removing Air from a system is a one shot deal and occurs when the system is installed. This is the process of Evacuation, where the system is pulled into a deep vacuum.

If air in your system is the final consensus, than it's possible that when your system was installed, they did not do a proper evacuation.

In order to fix this problem you're going to need a tech who will;

A- recover all the compromised freon from you AC

B- Pressure test/ and preform a leak inspection on you're entire system once more. If there was a leak they could've actually pulled air into the system while attempting to evacuate it.

C- install a new liquid line filter drier once it's determined there are no leaks in the system. Ask them to install a moisture indicator sight glass too so you'll know for sure when noncondesibles are a problem in the future.

D- Evacuate your system to 500 microns.

E- Recharge the system with new freon.

If your system is only 2 months old than my bet is that poor installation practice is why there is air in your system.
 
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Old 07-28-07, 03:05 PM
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Something doesn't sound right. How did the air get in the system? That's the million dollar question. The only possibility I can think of is a bad install. If your system uses 410a refrigerant, you have a heap of trouble brewing. Air=water vapor. The synthetic oil used in 410a systems will not give up the water even if a vacuum is pulled. You could be looking at one hell of a cleanup as well as equipment failure.
 
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Old 07-28-07, 10:41 PM
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You might also ask them how many R410a units they have put in. Ask him if he charged the unit by gas or did he put the freon in ,in liquid. As it has to go in in liquid. If they open the system it has to have a new drier and make sure its one for the R410a. Also just 500 microns pull down . Will not separate moisture from POE oils in R410a system. Dont forget you want all new R410a in the system
 
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Old 07-29-07, 04:32 AM
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I will follow up with them on Monday - the system appears to be operating effectively for the past 48 hours.

Someone asked how did he purge? I believe it was blown to atmosphere but I could be wrong......He had his pink tank of refrigerant and added some, blew some out,etc.

Maybe it wasn't the best trained tech...we'll see how things go on Monday. The contractor is a family owned business that's been around the area for a 100 years. I've got a feeling he'll take care of things.

Thanks again for your input.
 
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Old 07-29-07, 03:24 PM
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First...

If they didn't replace the air handler and refrigerant lines, your never going to have a properly running system period! It won't be a 13 SEER or eligable for a rebate from the utility either.
Secondly, the moisture CAN be removed, using oversized driers that have been only momentarily exposed to the atmosphere during brazing, and done under a nitrogen purge... because the moisture is locked into the oil, and it must be extracted from the oil by constant cycling through this drier.
Thirdly, Non condensables give you a high head pressure...and reduced capacity...its impossible to purge the air out, it stays at the top of the condenser. Now he can remove the air by recovering the charge, and pulling a deep vacuum, and re-charging the system. Thats the only way to remove air/non-condensables. I think what he did was add some refrigerant to a system with a leak.... He'll be back.
 
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Old 07-30-07, 06:11 AM
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They are coming back this morning. I'll be at work so hopefully they can get the job done properly - of course they could say the tech was incorrect in his initial diagnosis and that the system is fine.

We haven't had any issues since Friday night. How would one diagnosis air/non condensables in the system? What are the systems/indicators? What type of tools would a tech use to come up with that conclusion?

Thanks,
 
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Old 07-30-07, 11:44 AM
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I just rec'd a call from the tech who is supposed to be servicing the unit. He speaks with a very thick foreign accent so it was kind of a tough call to understand. But regardless he is at my house.

Basically he wanted to know if I had any problems with the system over the weekend. I said i wasn't around so I don't know. I said that on Saturday he told me i had air in the system and that if this is true then the system is contaminated it needs to be evacuated, a new drier must be installed, checked for leaks, and charged. His english got real bad after that and he hung up. I thought he said something about calling the office.

The person who took my call at their office didn't give me any information other than they will call me after they speak with the tech when he comes back at the end of the day.

I don't get a good feeling that the system is going to be serviced in accordance with the manufacturers specifications and according to some of the posts listed here.

What is the next suggestion? Call Carrier Customer Service and indicate I could have an issue with the installation and service of my new system? I concerned that this contractor may not perform the neccessary procedures to maintain the integrity of the system and I may incurr a premature failure of the system and get stuck without AC and with replacement costs.

I may be wrong, but it's not the way i normally like to start the week.
 
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Old 07-30-07, 12:17 PM
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Id Call Carrier Customer Service now for sure.
 
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Old 07-30-07, 12:33 PM
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I'm thinking "hacker".... Were you there for the install? Did they have a vacuum pump?
 
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Old 08-01-07, 01:30 PM
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If he only replaced the outdoor unit I think your screwed...

He was likely thye low bid...NEVER take the low bidder...always go somewhere in between... The old system can be cleaned out with liquid refrigerant with the metering device removed but this is so time consuming its not worth it... I don't know of anyone doing it. The old system had either alkabenzene oil or Mineral oil neither of which are compatable with POE oil...and you cant have any residual old oil in the system hence the liquid clean out.
 
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Old 08-03-07, 05:13 AM
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First, the outdoor unit and the indoor unit were replaced - there seems to be some confusion regarding this.

I did call carrier customer service and log a complaint.

I now have two dryers - the original dryer in my mechanical room by the indoor coil and now i have one outside by the condenser.

This seems peculiar to me. Two dryers?
 
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Old 08-03-07, 06:03 AM
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Is one drier on the skinny "liquid" line and one on the fat "suction" line ?

Hopefully so. The best place for the liquid line drier is inside close to the evaprator and the suction line drier normally gets put out by the compressor. If they did put a suction line drier outside it should be replaced or removed in a few weeks.
 
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Old 08-03-07, 09:11 AM
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Hi,

both liquid line dryer's are on the skinny liquid line w/ flow direction arrows pointed towards the indoor coil.

I've never seen this and did not know if having (2) dryers would restrict flow and what could possibly be the benefit??
 
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Old 08-03-07, 09:33 AM
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Not sure why 2 driers there They should be marked for R410a. You can just feel them with your hand somtimes. To see if there is a temp different from the in to out on them. If so they should come out then.
 
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Old 08-04-07, 08:12 AM
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If anyone is interested in what Carrier says when you report "shoddy" installation/service of their systems:

1. The customer may hire another local Carrier Authorized Dealer to inspect the installation/service at the customers expense.

2. The regional Carrier representative will contact the original installer to discuss the customer complaint.

3. The regional Carrier representative or the installing contractor may then contact the customer. Not will contact the customer but may contact the customer.

This is not what i would consider customer service - had i known this i certainly would have purchased a Trane system.

Quick story - I also have a Weber Propane Grill still under warranty that cost $1500.00 - almost a half of my ac system. There are couple of spots showing corrosion - Weber with no fuss immediately shipped me a new cover and burner rack. That is the type of service that says this Manufacturer cares about their customers.

I will always recommend Weber Grills, sad that i can't say the same for Carrier. And for my finally jab, I work for a global Arch/Engineering firm; approx 35,000 employees. I'll be honest, on the designs coming out of the US, Carrier Centrifugal or Air Cooled Chillers are not being specified by design engineers. It's almost always Trane. In fact the major US companies have direct purchase agreements w/ Trane.
 
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Old 08-04-07, 04:35 PM
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Myself and other technicians have said "it's the install that counts more than the equipment". The best equipment, poorly installed, will give poor results and will have numerous problems. It's for this reason I say forget about the brand name. Pick a good technician first, then follow his or her advice as to equipment selection.

I'm so sorry to hear about your bad experience. It gives all us technicians a bad name. But, perhaps others can benefit from the information you shared here.
 
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Old 08-04-07, 07:51 PM
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Jim, I do not mean to knock quality hvac mechanics, or Carrier Dealers. Obviously a consumer can certainly get an outstanding Carrier system that will deliver a high indoor environmental quality and will reach it's estimated life expectancy w/ few issues if properly maintained.

True - about the install, the highest quality equipment will not function as designed if installation is not performed according to manufacturers recommendations, specifications, industry standards,etc..

I think it's pretty tough as a consumer/client no matter what market you're in, hvac, automative, home improvement, accountants, lawyers, even barbers.... So much does come down to the individual servicing you.

If anything, i hope this reminds folks who read this to acknowledge their mechanic, technician, etc who are providing quality service b/c it doesn't seem like business as usual.

The HVAC & construction industry is booming - perhaps a few firms both residential and commercial have a labor demand that has required them to lower the "bar".

We'll see how this all turns out - it's interesting + frustrating because it doesn't make much sense but it could be a lot worst. I plan on finding out if this type of service is systemic with this installer. Not good for the Wash DC/Northern VA area.
 
 

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