Waterfurnace Series 5 6 ton skips stage 1 cool

Discussion in 'General Discussions' started by Chris Moody, Jul 2, 2019.

  1. Chris Moody

    Chris Moody New Member

    New waterfurnace owner, installed last fall. Heat worked great all winter, mostly stage 1 even on the coldest of nights. Recetly, we switched it to cool and Im having an issue where even though the thermostat is calling for C1, it goes right to C2. Dealer is being difficult and feeding me crap about sun load bla bla bla, I tried explaining to them from the waterfurnace documentation how its supposed to work, They argue and say the docs are wrong, o by the way they dont read any pubs or use the waterfurnace dealer portal. I should mention I have the intellizone 2 system with 2 zones. Both zones are calling for stage 1 but it blasts off to stage 2 every time. Has anyone experienced this?
     
    Last edited: Jul 2, 2019
  2. geoxne

    geoxne Active Member Forum Leader

    The Intellizone2 controls the staging of the HP based on many different control settings and the level of combined demand from the thermostats. It is very possible, depending on programmed control settings, a C1 demand from 2 thermostats will be interpreted by the Intellizone2 as a C2 call to the HP. Available settings depend on whether you have a Series5 or Series7 unit.
    These settings include-
    -#Zones
    -Zone%
    -Staging Options
    -Zone Priority

    I'm not sure why you are concerned about your HP running in C2? The Intellizone2 has decided what is required based on programmed settings and installed equipment.
     
  3. Chris Moody

    Chris Moody New Member

    I'm concerned for several reasons.
    1 stage 2 consumes 30% more energy. The system only runs for 10-15 mins so I'm also concerned for compressor durability.
    2. The thermostat says it's calling for c1 for both zones and when I look at system load it's 50%. The manual from water furnace says stage 2 should not be called until 51%. Theres no reason it should need stage 2 as the supply temp is the same in stage 1 and I'd prefer stage 1 which has a little slower fan speed to aid in dehumidifiing.

    I should also mention I have it set on normal staging. 70% per zone
     
  4. geoxne

    geoxne Active Member Forum Leader

    Along with a 30% increase in capacity and a 30% decrease in run time. I see no penalty there.
    Emerson/Copeland recommends a maximum of 10 cycles per hour for their scroll compressors. Most residential systems typically run at 3 to 4 cycles per hour at 50% duty cycle (time on = time off). There is plenty of safety margin for durability already there. A 10-15 minute run is a pretty good run.
    The documentation is wrong by 1%.
    IZ2Sim2Zone2StageCooling.JPG
    Supply temp is the same because the fan speed (CFM) has increased along with the compressor. The aircoil temp remains approximately the same.
    The cooling airflow is set at factory default of 15% less than heating airflow to aid in dehumidification no matter what stage it is in. I do agree that longer runtimes no matter what stage you are in will increase dehumidification.

    So all that being said, one way to defeat the IZ2 programming and control cooling staging the way you want is to install a 3rd "dummy" zone with a IZ2 Senso2Stat set to OFF and 25% zone. This will fool the IZ2 to calculate a 42% demand in cooling with 2 C1 calls and call Stage 1 compressor operation. Caution that this may cause unintended results as lags in Heat Staging (also not calling Aux if needed). This may require you to change Heat Staging to Faster1. Please consider the possibility of unintended operation especially if dummy Zone3 gets turned on inadvertently causing the HP to run with all dampers closed. The choice is yours.
    IZ2Sim3Zone2StageCooling.JPG
     
  5. Chris Moody

    Chris Moody New Member

    I talked to waterfurnace and indeed they did change the software but didnt bother to update the docs. This is frustrtating because it decreases system efficiency and in a way its false advertising. Also, the 15% reduction in airflow was not set by default , I had to go in and change it because the dealer is incompetent and didnt bother to setup half the settings as they needed to be. I supposes Im suffering from buyers remorse here as the system consumes over 4000 watts an hour and doesnt really perform any better than a high efficiency system would for probably half the cost. I was mislead by dealer and waterfurnace. I wonder if their specs for efficiency are also inaccurate since they made the software change. Most people wont know the difference. Not sure on your comment of 30% shorter runtime but it doesnt seem to be the case which is why the additional energy usage is frustrating.

    I shouldnt have to spend additional money to get the system to operate logically. They supposedly made the software change because systems werent satisfying set temp in C1. Isnt that why they have staging options. Why screw people who have well insulated homes. Faster 1 staging option kicks to stage 2 at 41% load unless thats inaccurate too......
     
  6. geoxne

    geoxne Active Member Forum Leader

    Try a no cost experiment and disconnect the Y2 wire in the IZ2 panel and see if she runs as you prefer over time. If you have Energy monitoring you can compare results to days with similar conditions and report back any comfort issues.
     
  7. Chris Moody

    Chris Moody New Member

    Would you happen to know which wire that would be, Im still looking but havent found it identified as Y1, Y2 in the manual.
     
  8. geoxne

    geoxne Active Member Forum Leader

    Sorry I was wrong there is no Y2 in the communicating IZ2 panel. It is in the IZ2 24v conversion board. You probably do not have one if your unit has the advanced control AXB board.
     

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