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  1. #1
    Join Date
    Apr 2012
    Posts
    60

    Carrier 24HNB9 compressor failure after 3 months... cause for long term concern?

    Hello.

    Back in June I installed a new Carrier Heat pump (25hnb924A003 -- 2 ton 2-speed 19 seer).

    It worked quite nicely throughout the summer. In September, with the pleasant weather here (Maryland)
    I shut off heating and cooling.

    Two days ago my hvac company came out for the fall maintenance. Turning on the heat pump revealed -- no heat!
    Fan coil pushes air, and the compressor seems to run (i.e.; cooling fan spins).
    The maintenance guy checks pressure levels, listens to a clicking noise from the compressor, and deduces that the scroll motor is malfunctioning. Which means it needs to be replaced.

    It is well under warranty, and I don't need heating or cooling for another month, so this is not a short-term problem.
    But why would this happen? I don't push the system much (most of the time it was running in dehumidify mode, and the house is only 1300sq feet). Even if I was pushing the system --3 months?

    So did I just get unlucky? The only weird thing I might of done is turning on heat mode accidentally, and then
    turning it off right away. But I can't imagine that (with all the delays the Infinity 'stat has built into it) would cause any
    kind of problems.

  2. #2
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,762
    Just make sure that when the compressor is replaced that they pull a proper vacuum on the system with a micron gauge down to 500 microns.

  3. #3
    Join Date
    Apr 2012
    Posts
    60

    pulling vacumn

    Quote Originally Posted by jtrammel View Post
    Just make sure that when the compressor is replaced that they pull a proper vacuum on the system with a micron gauge down to 500 microns.
    Thanks for the tip. It's always a bit of a challenge telling workmen such technical chores (they tend to look at homeowners as meddlesome dopes), but there are ways..

  4. #4
    Join Date
    Oct 2010
    Location
    Anderson, South Carolina, United States
    Posts
    7,762
    Quote Originally Posted by danielh View Post
    Thanks for the tip. It's always a bit of a challenge telling workmen such technical chores (they tend to look at homeowners as meddlesome dopes), but there are ways..
    I agree, I don't like it when homeowners tell me how to do my job but it is their house so I just smile and do what they want me to as long as it is not a task that will have adverse reactions, in that case I smile and explain why I can't do that. Some hvac guys don't even know what a micron gauge is much less how to use it. If they don't use a gauge and pull a vac down to 500 microns, or manufacture recommended level, then they could be leaving moisture in the system that will ruin vital components throughout the system.

  5. #5
    Join Date
    Apr 2012
    Posts
    60

    meddlesome homeowners occassionally correct :)

    Quote Originally Posted by jtrammel View Post
    I agree, I don't like it when homeowners tell me how to do my job but it is their house so I just smile and do what they want me to as long as it is not a task that will have adverse reactions, in that case I smile and explain why I can't do that. Some hvac guys don't even know what a micron gauge is much less how to use it. If they don't use a gauge and pull a vac down to 500 microns, or manufacture recommended level, then they could be leaving moisture in the system that will ruin vital components throughout the system.
    Can't say as I blame you, but sometimes we (homeowners) spend a lot of time researching a particular system (the one we are gettting in$talled).

    For example, I installed this system in parallel with an existing hydronic system (so I didn't bother installing resistance heaters). That makes is a bit complex;
    speaking loosely: the Infinity thermostat has to tell the boiler when to turn on (i.e.; when oat is low). This requires installing a special kit in the fan coil, that reports itself to the
    Infinity as a hydronic system. BTW: I learned this detail from asking on this site!

    Well, when they installed the system they didn't get that right. So the higher grade tech had to pay a visit, and he looked at the manual and discovered the reference
    to the special kit. At which point I smiled and handed over the 2 page spec sheet for the part. He took it well!

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