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  1. #1
    Join Date
    Mar 2008
    Posts
    2

    Non-standard wiring for Lennox CBX32MV060

    The local installer just put in a new Lennox system XP19060 / CBX32MV060 / T4147 stat.

    When the installer left the air handler produced cold air in cool mode but at a low rate (The air handler was hardly audible) even after runniong for over 10 minutes.

    When I checked the wiring in the air handler I found that the R, G, and C wires were connected to the T-stat (as expected) but the O, Y1 and Y2 lines were connected straight from the T-stat to the Compressor unit without being connected to the terminal blocks in the air handler.

    The manual shows these wires (O, Y1 and Y2) being connected at both the compressor and the air handler, but the installer says they have instructions to avoid connections to the air handler whenever possible and only connect these signals to the compressor.

    When I look at the wiring diagrams in the manual I can't see any way that the air handler can work properly without these connections.

    Is there any instruction from Lennox to skip these connections in the air handler ?

    Second (minor) question - the installer put a wet switch in the air handler drain pan, that is connected between the R terminal in the air handler and the R leads that go to the T-stat and compressor. The documentation for the wet switch says it should be in the Y line between the T-stat and the air handler. Since this is a 2 stage cooling, putting the switch on the 24VAC (R) connection does not seem unreasonable - any thoughts?

    Thanks,
    Nick

  2. #2
    Join Date
    May 2002
    Posts
    287
    They should be hooked up in the air handler. Call him back and have him look at the wiring diagram. The blower won't ramp up to the right speed without these wires hooked up. The wet switch seems to be hooked up right because of the two stage unit. He is breaking R instead of Y1 or Y2.

  3. #3
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,513
    tey need to connect y1 and y2 to the terminal block from the stat and the condenser. This will ramp the blower to the correct cfm for the tonage of the condenser. It will also tel the blower to ramp up or down for the required stage. You are running in default speed witch is low.

    If you have a two stage condenser then they also have to remove the factorie installed jumper between y1 and y2 so the blower can ramp to the lower cfm. If the jumper is left in the blower will ramp to high and stay there

    If this is a heat pump then they need to connect o for the reversing valve and also blower ramping

    the circut board has settings that HAVE to be set for the tonage of the condenser and setting for the blower cfm settings.

    Time to call the manager and tell them you want this unit set up properly.
    ayou also should ask to have the refrigerant level rechecked. I for some reason have a feeling if they cant set the airhandler up properly then they cant ajust the charge properly.

    also if the blower inst giving the proper cfm then the refrigerant chage can NOT be checked properly

  4. #4
    Join Date
    Mar 2008
    Posts
    2

    More connections questions

    Thanks - I checked the jumpers on the BDC3 board and they appear ok:
    - Adjust = Norm
    - Heat = Pin #1
    - Cool = Pin #3
    - Delay = Pin #4

    I re-read the XP19 Installation instructions. On page 7 it shows a wiring diagram for an XP19 to a CBX32MV and Signature stat. In this diagram the Y2 line from the stat goes directly from the stat to the XP19 Y2 input. There is a Y2 output on the XP19 that goes back to the Y2 pin in the air handler. I have an Elite series stat instead of a Signature stat. Should the Y2 signal be connected to the stat, air handler and heat pump in the normal manner, or as page 7 shows described above ?

    The XP19 and the t-stat wiring diagrams both show the L signal for equipment monitor. The t-stat describes this as lighting a red monitor LED. Are these compatible and should the installer connect the L wire too ?

    There is no humidity sensor in the t-stat and the DS connector in the air handler is not connected to anything. The air handler wiring diagram on page 17 of the CBX32MV Installation Instructions shows a jumper from Y1 to DS if no humidity control is used. Should DS be left unconnected or jumpered to Y1 ?

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