loop temperature

Discussion in 'General Discussions' started by nightowl, Dec 2, 2010.

  1. nightowl

    nightowl New Member

    I live in NW. Ohio and the weather has finally got down where the high is in the 20's. I noticed the aux. heat kicking in the other night. I checked my loop temp just out of curiosity and it was down to 42. Is that normal this early in the heating season? I have a closed loop system.
  2. bobpietrangelo

    bobpietrangelo New Member

    Yes it is normal
  3. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    What you need to look at is

    ...how comfortable you feel.

    Does your system have built in thermometers?

    I want to know the delta T in a loop system and the delta P through the machine. I live in northern Ohio and would hope that a system would not go AUX yet as we have much more cold coming.

    An additional issue may be opporator error in using the thermostat.
    Last edited: Dec 9, 2010
  4. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    I second that, the aux should not come on yet. Loop temps look fine. What kind of distribution system do you have, Radiant? Slab? Or forced air?
  5. nightowl

    nightowl New Member

    Forced air. The thermostat stays at 70 24/7, I don't touch it.
  6. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader


    ...the house really needs the AUX this early then the issue falls on the equipment. If the AUX is coming on while the heat pump will do all the heating you require then it becomes an issue with the controls.
  7. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    My guess is that the tstat is calling for aux heat before it should.
  8. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    A heat pump may have a balance point in the low 20's. That your auxiliary is coming on is only wrong if it wasn't designed to, yet.
    I certainly do not agree that something must be wrong.
  9. geome

    geome Member Forum Leader

    What is the make and model of thermostat?
    Is the compressor 2-stage?
    How long have you had the system?
  10. jrh

    jrh Member

    I agree, That might be the designed balance point.
    Could also be a stat setting
    EWT of 42 is certainly not a problem
  11. nightowl

    nightowl New Member

    Thermostat is a Water Furnace Model TA32E02. Single stage compressor. The system was already installed when i bought the house 5 years ago. The guy that services it is the guy who installed it and I think he said it is 10+ years old.
  12. geome

    geome Member Forum Leader

    WF, would you please post a link to the TA32E02 thermostat installation and operator's manuals?

    It appears that this thermostat was replaced by another WF model (at least in Canada) in 11/1994. I wonder if your system is 16+ years old? I would think WF could give you an installation date (and installation and owner's manuals) for the geothermal system based on the model number and serial number if you are interested and contact them.
  13. m159267

    m159267 New Member

    Not an expert but I encountered same situation 3 years ago with my E-Series WF. Good loop temp but hitting Aux far too often. Turned out I had a coil leak and lost a lot of refrigerant. Could this be the case here?
  14. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    A refrigerant leak

    in the coax heat exchanger is very possible. I did a replacement job on an older unknown loop system. The dead machine leaked a bunch of R-22 into the loops. The customer said the old machine had been condemned by the servicing contractor so I never thought to weigh out the charge when getting rid of the old unit.

    I almost replaced the heat exchanger on the new unit when my refrigerant leak detector when off when I was re-purging the loop field. It took a while to get it all out of the system.
    Last edited: Dec 9, 2010
  15. nightowl

    nightowl New Member

    Had the unit serviced, refrigerant was a little low. Big differance, 24 degrees and windy and unit is not running constantly and aux. not kicking in. We did figure the unit is about 14 years old.
  16. bobpietrangelo

    bobpietrangelo New Member

    It most of my designs, my balance point isn't reached until about 10-15 degrees. My own EH is locked out until 20 degrees.
  17. kandk920

    kandk920 Member

    EWT on Radiant w to w system

    Second week of Dec and my loop EWT is down to 38 on a 4T system heating 4200 sqft in East Central WI. Always seems to drop so fast, but keeps the house warm. Geo unit used about 1000 Kwh last month with daytime temps avg in the 30's and night time in the 20's. Not anything to crow about regarding heating cost, but not bad either.
    Last edited: Dec 9, 2010
  18. bobpietrangelo

    bobpietrangelo New Member

    What would the cost difference had been if you were using a gas boiler to perform the same function. Also this early in the season, you may have had to heat up the slab initially. Once the slab is brought up to temperature it will cost alot less to maintian it's temperature. Do not use any setback on your radiant floors.
  19. bobpietrangelo

    bobpietrangelo New Member

    $130 a month to heat your home when it is averaging 25 degrees outside, in a 4200 sf house, I think I would crow! Assuming you are paying the 13 cents/kw I found.
  20. kandk920

    kandk920 Member

    I have no idea what the cost difference would be using a gas boiler as the house is new, ICF construction, and now in it's second heating season. The heating load consists of the lower level's insulated concrete slab and main level's gypecrete slab, so I am certain they both heat and maintain temps differently. NG is currently the lowest cost fuel option in this region, so I always wonder if heating costs would have been different with a gas boiler vs the geo.

    And, yes, no setback with the radiant system, as it is a low temp system with floor loop water temp set to a 98 degree max it does not recover quickly, but maintains very well.

    So, yes, $130 for avg of 35 degrees (per utility bill) for the month isn't bad, but would it be the same or less expensive with a gas boiler system? Something I will not know with any certainty unless I install one.

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