When does your Aux Heat kick on?

Discussion in 'General Discussions' started by vortrex, Dec 10, 2018.

  1. ChrisJ

    ChrisJ Active Member Forum Leader

    Sometimes the aux is on the same breaker as the blower.
     
  2. vortrex

    vortrex Member

    I flipped the breaker labeled as "geo aux heat" and the entire system went off, stat too. The water pump was still running. Seems like they have it wired to the wrong breaker!? I will try the one labeled as "geo unit" next, once the system is back up and stable.
     
  3. nc73

    nc73 Member Forum Leader

    Oh that's just perfect :)
     
  4. vortrex

    vortrex Member

    I did just measure the air temp at a register that is about 25ft from the geo unit. On H9 it was 88.7F and on Aux Heat it was 97.3F. I will get the water temps later today. Looks like I need to take one of the covers off the unit to access that.
     
  5. nc73

    nc73 Member Forum Leader

    Air temps should be measured right at the return and supply (and get the delta), but the numbers look good to me. You don't need aux.

     
  6. vortrex

    vortrex Member

    I measured again about 6" before the filter on the return at 72.7F and about 6" above the unit on the supply at 98.6F. This was with it running at H9, fan on Speed 7, stat set to 70F.
     
  7. nc73

    nc73 Member Forum Leader

    25.9 delta is good. I get 27 on second stage and 24 on first stage. I would just disable the strips and monitor. You will save money. Fan speed will affect the register readings too. Slower will produce higher temps.
     
  8. vortrex

    vortrex Member

    I might have got a few more tenths out of it if I held the thermometer longer. I will look into disabling the Aux later today and see if it can handle the temps this evening. Thanks everyone for the advice so far.
     
  9. Stickman

    Stickman Member Forum Leader

    I'm a little late to the conversation. But to answer your original question, my aux heat comes on when the heat pump cannot maintain the set temp. I've got a 60 year old house with moderate improvements to insulation, etc... My experience has been that I usually set the thermostat to 72-73F, and aux will kick in when the outside temp is below 20. This reflects what my manual J calculated, and my equipment was sized for. Add wind (or an open window) to the picture and it'll kick in sooner. I do not have any outdoor reset/sensors adding to the control scheme.

    Your situation sounds like you're seeing what you should expect.
     
  10. nc73

    nc73 Member Forum Leader

    It is possible what Stickman says but worth a try. I think you can disable on the board itself, maybe a dip switch.
     
  11. vortrex

    vortrex Member

    Thanks for sharing your situation Stickman.

    One thing I thought about, couldn't I set the differential for Aux Heat to something high so that it won't come on unless it absolutely has to? Right now the differentials are set to .2, .5, 1.0. I will change the 1.0 to something higher and see what happens.
     
  12. ChrisJ

    ChrisJ Active Member Forum Leader

    What do the three numbers represent?
     
  13. vortrex

    vortrex Member

    As I understand it... stage 1 will come on when the temp falls .2F below stat set point, stage 2 will come on if it falls .5F below, and aux heat will come on if it is 1F below.
     
  14. ChrisJ

    ChrisJ Active Member Forum Leader

    Ok, that's what I thought. Stage one is actually 1-6, Stage two is 7-12. With 2 zones though maybe it will not go higher then H9 or H10.

    I think I heard Doc talk about a % adjust-ability with the intellizone.
     
  15. vortrex

    vortrex Member

    Interesting that you mention that because that was another question I had. I never seem to see it go above H10, but in the docs I saw there was H11-H12. I *think* I saw it go to H11 before when I was experimenting with settings but I cannot remember what triggered that. It sure seems like if I could consistently get H11-H12 it would save me from using the Aux much of the time. Any idea why with two zones it won't go to those last levels of heat?
     
  16. nc73

    nc73 Member Forum Leader

    That's good question there vortrex..I like my simple stage 1 and stage 2, low cost!
     
  17. ChrisJ

    ChrisJ Active Member Forum Leader

    I think it's because in a zoning situation one zone can't handle 100% of the heat pump capacity. Or it only goes to those last levels when both zones call at the same time.

    There must be an installer adjustable area of the thermostat where the % per zone is changeable.
     
  18. vortrex

    vortrex Member

    Ahh this would make total sense in my house. It is all open from 1st floor (zone 1) to 2nd floor (zone 2). The upstairs seems to almost "self heat" from the heat rising from the zone downstairs. Like right now zone 1 is running at stage 2 and zone 2 is off.

    I have been experimenting with changing the zone sizes myself. The WF way of doing this is confusing. I keep zone 1 set at 70 (which means 73%) and zone 2 set at 25 (which means 26%). If I try 70/45 it equates to 60% and 39%. The installer set it at 70/70, which seems so wrong to me since the upstairs zone assumes much of the downstairs rising heat and also is physically smaller.
     
  19. ChrisJ

    ChrisJ Active Member Forum Leader

    So it won't let you set any zone higher then 70%?
     
  20. vortrex

    vortrex Member

    Correct, the only size options are 70, 45, 25. Which aren't really %'s per se. I guess ratio is a better term? If I set it to 70/70 as the installer did it's 50% zone 1 and 50% zone 2.
     

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