Michigan Water Furnace Series 7 - what should I expect?

Discussion in 'Maintenance and Troubleshooting' started by vortrex, Jan 2, 2016.

  1. vortrex

    vortrex Member

    Had a zoned Water Furnace Series 7 system recently installed here in lower MI. The house is 2200 sq ft from '67, not the most efficient (half the windows have been replaced in the past year, still making improvements), panel roof, the first floor is 4'-6' below grade, and the living room is open to the 2nd floor with 26' ceilings.

    It's been a fairly mild winter, but even at that, the system seems to have a difficult time heating it. In 32F temps (maybe even up to the low 40's) the system never shuts off. It runs for a solid 24hrs each day. If I move the stat from say 68F to 70F it might take 6hrs to move it two degrees, or maybe it won't be able to at all. Also, no matter what the stat temp is set for the room temp will never reach that number. Even on the warm day the room temp will be 1 degree off. Using the stat as my billing system (power company still has not installed the meter yet after 4 months) it looks like I'm using in the $5-$6 range per day. Does that sound right? The "electric heat" does come on every day per the stat history.

    The contractor is coming back again to look at things, will be the 3rd time. I just need to hear from someone else on what I should be expecting. Thanks!
  2. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    The WF7 running "forever" is not an issue (generally). The "not reaching temperature" is.

    It could be low refrigerant; too small of a system; low EWT, but my instinct is pointing towards the setup.

    But first spend some time verifying the setup, especially your controls.
  3. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader


    The WF7 is designed to run forever, since it can modulate down to 20% of the load. If it gives you comfort, there is a link to a new built 2013 home with form insulation above which shows that it ran 22 hours in the last 24 hours at 32F outside temp.

    Make sure you don't run thermostat setbacks, set it to 1 comfort temperature and forget it. What size of heatpump do you have?
  4. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    We hope contractor has AID tool and can quickly view operating parameters, followed by a heat of extraction calculation based on temps and pressures measured at PT ports.

    A 50 YOA house with 26' ceilings is likely a bear to heat. We hope system tonnage is based upon a careful ACCA Manual J load calculation

    Thermostat being a degree or two off isn't a big deal...configure the offset or bump it up a degree or so.
  5. Neokane

    Neokane Member

    I live in Iowa. My house was built in 78. 2061 sq ft. split foyer with a lower level garage.
    I have a WF series 7. 5 ton unit (no DHW) I used 460 kWh in the month of November to heat the house at 71 degrees.
    My unit does run a lot on heat 1 and ramps up occasionally. When it gets cooler sometimes it runs on heat 2.

    Hope this helps
  6. geoxne

    geoxne Active Member Forum Leader

    You mentioned a zoned system. I assume the Intellizone2 (IZ2). Do have some zones that are being satisfied?

    If so, perhaps the zones are not weighted by percentage properly in the IZ2 zoning system configuration.
  7. vortrex

    vortrex Member

    Some more details...

    The house was originally designed with two gas furnaces, which it had up until the geo went in. One furnace for the first floor and one furnace for the second floor. The AC was connected to the upstairs unit. In the winter the gas furnace for upstairs would never come on since it's so open to the floor below and got a lot of that heat. The gas furnace for the first floor was able to adequately heat the house even when hit -20F last winter.

    Now with the geo, there is the IZ2 system. One zone is for the first floor and one for the second, same as the functionality of the previous two systems and the behavior is the same too. Zone 2 never comes on for heat since the heat from zone 1 rises (very open floor plan).

    I don't know what size heat pump was installed. How can I check? It is a vertical field with 3 holes. I heard numbers of 175'-200' per hole before the install happened, but I'm not sure what the final numbers were. The contractor is factory trained and yes they have the AID tool. They will come out again this week and explore some more "staging options".

    Neokane - my Nov was 862 and Dec was 1275. These have been abnormally warm months for MI too. Stat is set at 70 and we drop it to 68 at night. It spends a fair amount of time on heat 2 and even goes to electric every day.
  8. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    One issue is the setback, when it then gets the signal to from 68F to 70F, the electric supplement heat will kick in. Keep it at 70F if that is the temp you want.
    Give us your model number, that will show the size.
    In addition, with the zoning system, the max the controller allows to go into 1 zone is either 60% or 70%, make sure it is setup that way, since the setting might be less.
    Thus the unit must be sized larger in order to heat the whole house through only 1 zone.
    The key is to oversize the unit with open floor plans, others it will have a hard time satisfying a zone, since you only have 70% of the capacity. Known WF issue when combining 7 series with the Intellizone 2.
    Last edited: Jan 3, 2016
  9. vortrex

    vortrex Member

    The model # is NVV048A111CTR0KN.

    OK, will try to stop using the set back at night. I was only doing that because it does get a little too warm upstairs while sleeping.

    Interesting note about the single zone output. I will bring that up with the contractor.
  10. vortrex

    vortrex Member

    Looking at the stat under zones I see Size = 70 and Norm = 50% for Z1 and Z2. Is this what you were referring to?
  11. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    So you have a 4 ton system, 2 zones, you should set zone 1 to 70 and zone 2 for 30% for size. Make sure you set other zones you don't have to zero.
    Turn down your thermostat for upstairs so it does not get too warm.
    Installation manual attached, size setup and priority setup starts at page 16

    Attached Files:

  12. vortrex

    vortrex Member

    Thanks for that info. I got into the config for the first time and set zone 2 for 25%. That raised zone 1 from 50 to 73. I guess in the summer I'll have to reverse those numbers since the upstairs needs almost all the cooling. Downstairs stays pretty nice with it mostly below grade.

    I see that the zones are both set to comfort and faster1.
  13. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    let us know how it goes.
  14. geoxne

    geoxne Active Member Forum Leader

    Alert your contractor to WF Tech Bulletin-IntelliZone2 Configuration Update 2015-TB15111601 dated 11/16/2015.
    It might require an software update of the IZ2 system. I am not sure this will be a complete solution.
    A good first step. You might not have to switch seasonally if your cooling load is significantly less than your heating load. I would wait to make the adjustment if making cooling setpoint becomes an issue.

    Stratification is the problem here. Still air can stratify at .5F per foot. 10 ft between floors can get you a 5F degree difference. Increased air flow can help but a dedicated destratification system may be required to overcome the natural tendency for warm air to rise. Ceiling fans?
  15. vortrex

    vortrex Member

    Do you have a link to show what's in that tech bulletin?

    The contractor did mention ceiling fans. It's really not possible though.
  16. geoxne

    geoxne Active Member Forum Leader

  17. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Actually they are Technical Bulletin tips for the IntelliZone2 firmware version 2.01 (release date 10/15/15) and Variable speed product. More or less detailing what is already in the installation manual.
    WF gave permission to forward it. It is attached.

    Attached Files:

  18. vortrex

    vortrex Member

    Thanks for that. I made some changes to certain parameters and then it suddenly got cold here (single digits to mid teens). Hard to tell if it did anything for me. Looks like the last 24hrs cost me $13, which seems excessive? The old gas furnace was not that much.
  19. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Lets say your 4 ton unit runs 24H with 4 KW, which is the max the unit can consume, so about 90 KW for 24 hrs, you would need to pay 14 cents/kwh, which I believe you do not in Michigan. So either your aux came on, or your $$$ are incorrect. The stat might be wrong with the $$$. How do you know it cost you $13 in the last 24 hrs?
  20. vortrex

    vortrex Member

    That's correct, the aux came on quite a bit. I programmed 11 cents into the stat, which seems accurate. I still don't have a meter yet to see how much my real bills are. Here's a picture of yesterday's usage.

    Attached Files:

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