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  1. #1
    Join Date
    Aug 2010
    Posts
    9

    AC Compressor runs constantly, tech says I need a new one.

    I have noticed that over the past few days my AC is on constantly (the compressor and blower) from about 12pm to 11pm, it doesn't turn on and off, it is just on constantly. Normally it would just turn on a couple of times an hour. I live in Las Vegas, so it does get pretty hot, but it is not abnormally hot for this time of year. The AC keeps whatever temp I set, it just stays on constantly....

    Figuring this could lead to bigger problems, and a bigger electric bill I called the HVAC company that installed the unit originally when the home was built 11 years ago (I am the second owner). They came out and the guy hooked up his hoses and meters on the outside unit while it was running and came back with that there is high suction pressure and low amp draw meaning that the compressor wasn't working properly. He said that I needed a new compressor, and of course that I should seriously consider a whole new unit. Does that sound like an accurate assessment based on the info he provided? I told him for expensive stuff like that I always get three quotes.

    I was sort of frustrated that he didn't check the evaporator coils. So I went and checked those in the attic (and lost 5 lbs in water weight in the process) and they looked a little dust covered but nothing too bad, so I went and got coil cleaner and cleaned and rinsed those. The unit cools a little better now.

    One thing I did notice when in the attic is that the incoming refrigerant line was cold, and the outgoing one was pretty warm to hot. So it seems like the compressor was moving something. The other thing was that there was a constant whooshing sound coming from the refrigerant lines, almost as if there were air in the lines or something. I had previously heard this sound through my ceiling for about a year now. Could this whooshing mean anything? Could a flush of the refrigerant fix this? I just wanted to see if you guys had any thoughts on this before I paid another "diagnostic" fee for someone else to come look at the unit.

    Oh here is the technical data: York 5 ton split unit R-22, cooling about 2200 sq-ft.

  2. #2
    Join Date
    Sep 2009
    Location
    Arnold mo
    Posts
    3,788
    Do some research on the company you had come out & see what their reputation is. Also do the research first on any other company you have come out for a second opinion. It's all you can do, unless you really read a lot of threads on here and get better educated on ac systems.

  3. #3
    Join Date
    Feb 2010
    Location
    In a boiler room
    Posts
    6,914
    I would get a second tech to look at it.

    He may be right about the comp but it sounds like he didn't take the time for a complete evaluation of the whole system.

  4. #4
    Join Date
    Jan 2010
    Location
    Athens GA
    Posts
    1,234
    Hard to tell from here but itb sounds like you could benifit from a second opinion and maybe a 3rd and 4th opinion.
    I have no way of knowing but have been told that it ia harder than haties to find good a/c guys in your home town.Ask everyone you know who they use and if they are good or bad.Anyone advertizing a Nate trained service person should have a leg up,but ask ask ask around.

  5. #5
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,826
    When calling a service company for AC or heat, the important question to ask is "how do you size a replacement (AC system or Furnace as appropriate to the season or problem). If they tell you they do it by load analysis, Manual 'J' load calculation or similar, feel confident they are a company on which you can depend. If they say "by square footage, or by my vast experience or by the size of the existing system" or anything similar, thank them and hang up. Call the next company in the phone book. This is the easiest way for a layman to determine if the company at least attempts to do good work. If they're not cutting the sizing corner, they're likely not cutting other corners as well. But if they're cutting that corner, you can bet they're cutting every other corner they can.

    Okay, now that you know how to test them, make some phone calls and see if you can find one company that passes the test and services your area. You need a real service company, not a wannabe. Based on what you've told us already, you got someone who knows only slightly more than you about the vapor compression cycle. You need someone who knows it frontwards and backwards and all ways in between. That'll be the company that does load analysis every time.
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  6. #6
    Join Date
    Sep 2009
    Location
    Arnold mo
    Posts
    3,788
    Quote Originally Posted by skippedover View Post
    When calling a service company for AC or heat, the important question to ask is "how do you size a replacement (AC system or Furnace as appropriate to the season or problem). If they tell you they do it by load analysis, Manual 'J' load calculation or similar, feel confident they are a company on which you can depend. If they say "by square footage, or by my vast experience or by the size of the existing system" or anything similar, thank them and hang up. Call the next company in the phone book. This is the easiest way for a layman to determine if the company at least attempts to do good work. If they're not cutting the sizing corner, they're likely not cutting other corners as well. But if they're cutting that corner, you can bet they're cutting every other corner they can.

    Okay, now that you know how to test them, make some phone calls and see if you can find one company that passes the test and services your area. You need a real service company, not a wannabe. Based on what you've told us already, you got someone who knows only slightly more than you about the vapor compression cycle. You need someone who knows it frontwards and backwards and all ways in between. That'll be the company that does load analysis every time.
    Hate to dis-agree with YOU, 'cause I really like & learn a lot from your post. But that part in red is wrong. The important question to ask when you call a service company is "Do you know how to service & repair, or do you just know how to sell me something new?" Lots of companies out there sending out "salesmen" in the disguise of servicemen that don't know squat about diagnosing a system, much less serviceing & repairing them.

  7. #7
    Join Date
    Oct 2003
    Location
    Washington
    Posts
    7,405
    Quote Originally Posted by tipsrfine View Post
    Hate to dis-agree with YOU, 'cause I really like & learn a lot from your post. But that part in red is wrong. The important question to ask when you call a service company is "Do you know how to service & repair, or do you just know how to sell me something new?" Lots of companies out there sending out "salesmen" in the disguise of servicemen that don't know squat about diagnosing a system, much less serviceing & repairing them.


    No, Skip is 100% right on, without question. If a company will size equipment right, there is a better chance than not, that they know what they are doing in the other facets of our business.


    Oh, and to the original poster. Your system should be running constantly at design temperatures. That lets you know it is sized properly. Remember, an air conditioner uses more electricity stopping and starting as opposed to "steady state" operation.

  8. #8
    Join Date
    Jun 2006
    Location
    Richmond, VA
    Posts
    2,671
    Quote Originally Posted by tipsrfine View Post
    Hate to dis-agree with YOU, 'cause I really like & learn a lot from your post. But that part in red is wrong. The important question to ask when you call a service company is "Do you know how to service & repair, or do you just know how to sell me something new?" Lots of companies out there sending out "salesmen" in the disguise of servicemen that don't know squat about diagnosing a system, much less serviceing & repairing them.
    I bet you could call every HVAC company in the phone book and they will all say "why yes sir, we service and repair!
    It's not the Brand with the fewest repairs-It's all in the install!!! Attention to detail and using the best materials!

  9. #9
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    4,451

    Arrow What was the head pressure as compared to the suction pressure?

    Quote Originally Posted by SeanCLV View Post
    I have noticed that over the past few days my AC is on constantly (the compressor and blower) from about 12pm to 11pm, it doesn't turn on and off, it is just on constantly.

    Normally it would just turn on a couple of times an hour. I live in Las Vegas, so it does get pretty hot, but it is not abnormally hot for this time of year. The AC keeps whatever temp I set, it just stays on constantly....

    Figuring this could lead to bigger problems, and a bigger electric bill I called the HVAC company that installed the unit originally when the home was built 11 years ago (I am the second owner).

    They came out and the guy hooked up his hoses and meters on the outside unit while it was running and came back with that there is high suction pressure and low amp draw meaning that the compressor wasn't working properly.

    He said that I needed a new compressor, and of course that I should seriously consider a whole new unit. Does that sound like an accurate assessment based on the info he provided? I told him for expensive stuff like that I always get three quotes.

    I was sort of frustrated that he didn't check the evaporator coils. So I went and checked those in the attic (and lost 5 lbs in water weight in the process) and they looked a little dust covered but nothing too bad, so I went and got coil cleaner and cleaned and rinsed those. The unit cools a little better now.

    One thing I did notice when in the attic is that the incoming refrigerant line was cold, and the outgoing one was pretty warm to hot. So it seems like the compressor was moving something. The other thing was that there was a constant whooshing sound coming from the refrigerant lines, almost as if there were air in the lines or something. I had previously heard this sound through my ceiling for about a year now. Could this whooshing mean anything? Could a flush of the refrigerant fix this? I just wanted to see if you guys had any thoughts on this before I paid another "diagnostic" fee for someone else to come look at the unit.

    Oh here is the technical data: York 5 ton split unit R-22, cooling about 2200 sq-ft.
    Where is he taking the suction pressure at?
    What was the head pressure as compared to the suction pressure?

    Did he check superheat & subcooling?

    First, he should have checked to see if the condenser coils & fins were clean & CFM was up to par.

    A dirty condenser or lack of airflow through it could run both head & suction pressures up, especially in high Vegas temps.

    He should have checked the condenser discharge air temp/split as compared to the indoor Temp'split.

    Numerous things can affect the amp draw...
    Also, most 5-Ton systems have very low airflow compared to what is called for.

    There are ways to check the efficient performance of a compressor.

  10. #10
    Join Date
    Sep 2009
    Location
    Arnold mo
    Posts
    3,788
    Almost getting into petty nit-picking here about how our posts are worded. To be clear, the point I was trying to make is that there are a lot of companies out here that are totally structured around sales, sales, sales, sales. And that by doing some research and asking friends & family & neighbors & co-workers, the op may find a company with a good rep in regards to being willing and able to keep an existing system running, rather than just selling a new one.
    As far as the manual j deal being a good indication of a company-that is debatable. Some companies are real good at the "dog & pony" show thing. May even have a blower door & duct blaster & stuff. Some companies are real good at repairing stuff that have never done a manual j.
    A company having a good reputation through word of mouth of satisfied customers is more telling, to me, than anything else.

  11. #11
    Join Date
    Oct 2003
    Location
    Washington
    Posts
    7,405
    Quote Originally Posted by tipsrfine View Post
    Almost getting into petty nit-picking here about how our posts are worded. To be clear, the point I was trying to make is that there are a lot of companies out here that are totally structured around sales, sales, sales, sales. And that by doing some research and asking friends & family & neighbors & co-workers, the op may find a company with a good rep in regards to being willing and able to keep an existing system running, rather than just selling a new one.
    As far as the manual j deal being a good indication of a company-that is debatable. Some companies are real good at the "dog & pony" show thing. May even have a blower door & duct blaster & stuff. Some companies are real good at repairing stuff that have never done a manual j.
    A company having a good reputation through word of mouth of satisfied customers is more telling, to me, than anything else.

    Now, that's something I'm sure we can all agree with. But I would be surprised if these customers would give good referrals if they didn't get a properly sized system. Manual J is the best tool we have to ensure that. The days of guessing are over boys. No matter how hard you want to stick to your old ways!!

  12. #12
    Join Date
    Jun 2007
    Location
    Round Rock
    Posts
    3,397
    Look at it realistically. It's friggin' hot outside. Aside from manual J and nate techs to work on, which isn't going to solve doo doo at this point. You have an 11 year old unit which I will assume has worked well for several years now. There are a few things that could be wrong. But, it is 11 years old. Yeah the guy can piss around with it, fix one problem and 2 more will pop up. Then the dude will own it. Anybody on here that is a professional knows what will happen and probably has had it happen and will again, trying to be a good samaritan. When it's all said and done, we should have called it what it is and moved on. Who has the time to make a 11 year old unit their hobby?
    I like DIY'ers. They pay better to fix.

  13. #13
    Join Date
    Sep 2009
    Location
    Arnold mo
    Posts
    3,788
    Quote Originally Posted by seatonheating View Post
    Now, that's something I'm sure we can all agree with. But I would be surprised if these customers would give good referrals if they didn't get a properly sized system. Manual J is the best tool we have to ensure that. The days of guessing are over boys. No matter how hard you want to stick to your old ways!!
    No, it's not. The manual J is just one of the tools that goes into it. The first step is having a professional energy audit performed. Blower door, duct-blaster and hopefully an infra-red camera in conjunction with these. The very first step is determining where & how good is the houses thermal envelope. Performing a manual J without this being done first is as wrong as throwing a system in without a manual j. Even new homes have serious air leaks & insulation issues.
    The eskimos lived in a house made of snow & when it was minus 50 outside they had an inside temperature of plus 20 ON BODY HEAT ALONE! This is what Building Science is about & the days of just doing a manual j "is over boys".

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