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  1. #1
    Join Date
    Jul 2004
    Posts
    76
    So we're almost done, and things have gone good so far, slower than expected, but hey it's a retro-fit destined for the wall O' pide.

    There's this one point that keeps bugging me, though. Its the zoning system.

    Here's the equipment I've got.
    Trane
    Outdoor Model Number: 4TWX6048A1
    Indoor Unit(s): 4TEE3F49A

    Thermostat: Honeywell TH8320U (Neat by the way)
    Zone controller: Honeywell EMM-3U (2 zones)

    Now the question I have is I have a 3 stage heat system (2 compressor and 1 strip) The thermostats are setup for a 3 heat / 2 cool unit (0170 = 12) When I read the install manual for the zone cntrol, it says its for a 2H/2C setup. Under equipment wiring (page 8) it gives the wire config for using the 2nd heat stage for the compressor or the strips then says "To control a two-stage heat pump with auxiliary heat, select the TZ-4 TotalZone Zone Control Panel."

    Looking at the book and the wiring diagrams some more it looks like the panel sets W2 on the call for 2nd stage, and Y2 / E are jumpered to that, depending on what the 2nd stage is susposed to be.

    So far I've asked about this three times, and gotten varities of "We always install this one." to "Don't worry aobut it."

    Am I reading this wrong? I don't want to pass on the features of having a multistage thermostat to have the compressors 2nd stage controlled by a timer. (I don't know how else it would ever come on for heating, I don't much care about the cooling.)

  2. #2
    Join Date
    Sep 2003
    Posts
    1,311
    You are correct in that the TZ-4 should have been used. Another option is the networked zone system. As you have found the EMM-3U is designed for up to 2 heat/2 cool stages.

  3. #3
    Join Date
    Jul 2004
    Posts
    76
    So I talked to my contractor, and the result was a compromise of sorts. At least the panel is currently wired for 2nd stage compression to work. (long story)

    So now I'm left with a choice.
    1) Leave the current setup.
    Equipment above.
    Wired so 2nd stage compression and Aux heat are jumpered together at the panel with Aux passed through a ODT switch at the compressor set to the caculated balance point of the system.

    2) Replace the EMM-3U with a TZ-4 at some additional cost. Since the contract doesn't specify WHICH model thermostats are used, he mentioned he could just get some two stage ones and solve the problem that way.

    There's a lot of great knowledge here, and I'd appreciate comments. My main focus with this system is economic savings for heating.

  4. #4
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    I see #1 as better for savings,as the aux heat is locked out ,at temps you don't need it.

  5. #5
    Join Date
    Jul 2004
    Posts
    76
    Originally posted by dash
    I see #1 as better for savings,as the aux heat is locked out ,at temps you don't need it.
    Should have mentioned that, the ODT switch would get left in place with number 2. I'd use the stats for the lockout, but their lowest lockout temp is 40, and the balance point is 35.

  6. #6
    Join Date
    Jun 2004
    Location
    Dallas
    Posts
    179

    Bent...

    Hello Bent-

    I, too am looking at the EMM-3u for a 2-zone setup running with a trane 2 stage cool/VS. (I have gas heat, though)

    Are you happy with the EMM-3U? Is it difficult to work with? Did you use honeywell dampers or others? Did you use a bypass or a dump?

    Thanks so much for any input or advice on this zone controller.

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