89 degree air - hot enough?

Discussion in 'General Discussions' started by BlueWRXPride, Jan 30, 2022.

  1. BlueWRXPride

    BlueWRXPride New Member

    We've been having a decent cold stretch in upstate NY with several nights between 0 and -10 F over the past few weeks, and days that are only 10 to 20 F. I had been concerned seeing my EWT dropping from around 37 in the beginning of the month to 33 F now. Having read some on this forum, it sounds like anything over 30 F is nothing to sweat about, so I do feel somewhat reassured about that. Still, my system has been struggling to keep the house warm. We have it set to 67 overnight and 69 in the day, and I've been finding myself turning on the fireplace to help get the temp back up. My system has been running in stage 2 for the past few hrs, and the air leaving is at 89 F. Should it be any warmer than that? If not, then maybe it's just a matter of my house not being as well insulated as I'd like.

    FYI there is an electric backup, but I keep it disabled just because it uses so much electricity.
     
  2. ChrisJ

    ChrisJ Active Member Forum Leader

    My air temp is mid to low 90’s.

    You may have some ductwork that’s in cold areas or under insulated ducts.

    Some air sealing and insulation upgrades on the house would help for sure.

    Chris
     
  3. BlueWRXPride

    BlueWRXPride New Member

    That leaving air temp is as reported by the heat pump, not at the exit of the air vents. So it wouldn't be impacted by the ductwork.
     
  4. gsmith22

    gsmith22 Active Member Forum Leader

    if loop temp is low 30s and heat pump can't keep thermostat at temp setting, then your heat pump's heating capacity is too small for your house's heating load. heat pumps are rated at 32F so low 30s is totally fine. I don't know that leaving air temp of the heat pump is going to necessarily tell you anything in isolation. Sounds like if you switch on elec heat, it will come on and try to get thermostat to set point implying that you heat pump can't keep up. Three ways to fix that issue - air seal and insulate to get your house's heating load down, get a larger heat pump to better match your house's heating load, or do both and meet in the middle.
     
  5. ChrisJ

    ChrisJ Active Member Forum Leader

    Uninsulated or leaky return ducts could certainly lower air temps enough to affect leaving air temps at the point measurement.

    Testing heat of extraction of the heat pump would be the best way to find out if unit is operating to spec.
     
  6. BlueWRXPride

    BlueWRXPride New Member

    How do you do that, the delta between entering and leaving water? Last check was entering at 32.7 and leaving at 27.1.
     
  7. gsmith22

    gsmith22 Active Member Forum Leader

  8. SShaw

    SShaw Active Member Forum Leader

    Heat of Extraction (HE) = GPM x DELTA-WATER-TEMP x 485

    Compare HE to the unit's performance tables.

    You have the delta-temp. You just need to know the flow in GPM.
     
  9. BlueWRXPride

    BlueWRXPride New Member

    21.5 GPM so my HE is 58394. I have a ClimateMaster Tranquility 22. Not sure where in the massive manual I check that against.
     
  10. gsmith22

    gsmith22 Active Member Forum Leader

  11. Stickman

    Stickman Active Member Forum Leader

    What size Tranquility 22 do you have? Are you sure about the 21.5 gpm? That’s 50% more than the highest flow rate on the performance tables
     
  12. xSpecBx

    xSpecBx Member

    Assuming the system is operating as it should, and from what you have said it seems to be, I think your problem is bouncing the temperature around in those extreme temperatures.

    In order to get from 67 to 69 in extreme cold, you need a lot of BTUs, more than you need to just maintain, and the system just isn’t large enough or the heat loss is too great to overcome. GSHP are not like an oil boiler belching out 140 degree air from the register. My geo installer recommended setting the temp and leaving it alone, so I would recommend putting it at 68 and not touching it, at least when you have a good cold snap.

    In your case, you’re probably losing slightly less btuh than the system produces when you’re doing that temperature adjustment in that extreme temperature so it’s going to take a while to get up without supplemental heat.

    My duct temperatures is generally around 90, give or take a couple degrees, with the thermostat set to 68 and we have had no issues maintaining temperature down to 0.

    My monitor is www.welserver.com/WEL1091/ if you want to look for yourself. We hit 0 degrees last weekend and the system ran a bit more than normal, but loop temperatures stayed healthy and house stayed comfortable.
     
  13. BlueWRXPride

    BlueWRXPride New Member

  14. Stickman

    Stickman Active Member Forum Leader

    I’ve got a 4 ton CM as well, and I’m flowing about 9 gpm (lower than ideal, I know). I’ve measured this with a temporarily attached flow meter and by using a pressure gauge at the P/T ports. Are you able to do either? If your thermostat is accurate, you might be over-pumping. Or the data is wrong.

    My LAT is typically at or around 90F too. This coincides with the performance data.
     
  15. BlueWRXPride

    BlueWRXPride New Member

    No, I don't really have any equipment to measure the GPM in a different way. Assuming all the other parameters shown on my thermostat seem to make sense, like the entering vs leaving water temperature, is it most likely the GPM reading is bogus?
     

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