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    mcolley's Avatar
    mcolley Posts: 1, Reputation: 1
    New Member

    Jul 30, 2010, 08:41 PM
    Free hvac advice
    I have a rent house with 2 air conditioning units - 1 upstairs and 1 downstairs.The down stairs unit was not cooling properly and an HVAC contractor told me the air handler needs to be replaced. AHS Insurance will cover replacement of the air handler but the contractor will charge an additional $1000 for non-covered associated charges.

    I am trying to make a decision whether to replace only the air handler or replace the outside compressor at the same time. I have talked to several different contractors and received different opinions regarding R410 and R22 issues.

    One contractor told me that if I replace the inside unit with an R410 unit, he can use a valve to make it compatible with the existing outside R22 compressor. Another contractor told me that if I went that route, when the outside compressor fails, I will have to replace the inside unit at the same time (even though its R410). Help - I am mechanically challenged and trying to understand so I make a good decision.
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
    Uber Member

    Jul 30, 2010, 09:28 PM

    It boils down to this:

    The refrigerent oils used in R22 are R410 are not compatible.
    The TXV (valve) is different.
    The lineset size COULD be different.

    Fix #1: replace all of the components including the lineset

    Fix #2: Flush the lineset. (In your case flush lineset & coil)

    Cost wise, it's not an easy call in your case. Flushing doesn't come cheap when you factor in labor and the cost of the compounds.

    When upgrading from R22 ro R410 most will choose to replace with matched components and also the lineset unless it's really difficult to replace the lineset, then the lineset might be flushed.

    Systems don't get the SEER ratings and don't qualify for energy credits unless the SYSTEM meets the requirements, Using a non-reccomended coil means the credit is lost.

    Does that help any?
    Cam1266's Avatar
    Cam1266 Posts: 1, Reputation: 1
    New Member

    Jun 4, 2013, 10:26 AM
    I have a Lennox AC unit outside. The fan will not come on. Basically it free spins by hand but will not come on. No bad noises, Tried the Capacitor but still didn't work. It has a Booster on the capacitor could that be bad and not let the fan operate ? It clicks on from the inside and it sounds like the compressor comes on. It was working properly and now this issue. Is there a relay or something that is simple to replace ? Is there anyway I can trouble shot this myself ? There is very limited funds and can't afford a couple hundred dollars to diagnous the problem. I am pretty handy and trying to do this for a single moms home with two young boys. It is getting hot. Trying to help. Can you assist ?
    KISS's Avatar
    KISS Posts: 12,510, Reputation: 839
    Uber Member

    Jun 4, 2013, 09:29 PM
    The compressor is a lot of times virtually silent. You can tell if it's on by feeling it.

    The "click" is a good sign, but power for that "click" comes from the furnace power.

    If we "assume" that the outside unit made a click and the fan AND compressor did not turn on, you have to look at the power source for the AC unit.

    Usually on the wall there is a disconnect and usually the fuses or breaker are inside the house. The disconnect has an orientation for on and Off which should be marked. So, when someone covers the AC unit, they pull out the piece in the disconnect and turn it around.

    So, I would look there and in the breaker box. The breaker for the AC should bea dual pole rated for 40-60 Amps.

    A tripped breaker can be moved toward the ON position with some springy play. A non-tripped breaker will be solid.

    A "common" failure point is the relay in the AC itself, but this is where it starts to get scary.

    I do have to ask you if your comfortable using a multimeter or have one and are you comfortable working near 240 VAC?

    A lot can be learned from inspection.

    Unless the disconnect is pulled, there is 240 VAC in the outside unit.
    There is 24 VAC that usually comes from the furnace and will be energized when the AC calls for cooling.

    The fan/capacitor is another failure mode.

    You do need to verify that the compressor is running.
    You also need to verify that 240 VAC is going to the compressor and the fan.

    With the disconnect pulled and the electrical covers removed, you may try to post a pic of what you see and inspect the contacts of the relays and look for loose connections.

    Right now, I'll leave it at that.
    Be careful.

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