Basement floor too cold?

Discussion in 'Maintenance and Troubleshooting' started by rebelrobin, Jan 17, 2011.

  1. rebelrobin

    rebelrobin New Member

    Guys, I can not get my TETCO 3 ton unit to generate greater than 17-19 degrees delta between EAT and LAT. All other measurements are in spec. Filter/coil is clean. Tonight I measured the cement floor that the unit is sitting directly on and it measured 60 degrees. My return temps are around 70. Could the floor temp be contaminating the EAT with cool temps by conducting through the floor pan inside the air handler box? Thanks for any help.
  2. geome

    geome Member Forum Leader

    Did you take the EAT and LAT measurements immediately before and after the air coil?
  3. rebelrobin

    rebelrobin New Member


    I took the EAT at the top of the return duct on the back of the furnace and the LAT directly above the Fan supply plenum.
  4. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader


    Get as close as you can, (with out touching), the coil on both entering and leaving sides. Allow about 6 inches away and tend to stay in the center of the air flow with all doors and stuff in place.

    I do not think the floor has any effect, but I learn new stuff every day.

    Keep us posted.

  5. rebelrobin

    rebelrobin New Member


    I measured the EAT/LAT closer to the coil as you suggested. Delta is now 22 degrees which seems to me OK. I also found my condensate drain hose was allowing cold air to be sucked back into the air box. Not much (3/4 inch hose) but still something. I am back at looking for air leaks in the home. One place for me to fix is the uninsulated dining room floor. It has an old stone basement underneath with hardwood floors, no leaks but the floor is cold (55).
  6. geome

    geome Member Forum Leader

    Interesting. If your drain has a trap, perhaps it has dried out and safely pouring some water down the drain will help?
  7. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader


    Good job on taking the temps. Next project is to really seal the duct work. I would start with the return system. I use duct butter or duct tape in a can. My favorite is water based with little or nothing in the way of VOCs. When cured it is fire rated. Any gaps bigger than about 1/8" will need a little help like good aluminum foil tape or a good silicon caulk. Then move on to the supply side and do the same. Any leakage in the duct work is too much.

    Then get at tightening the foundation and basement envelope.

    OBTW that hard wood floor sounds like an excellant spot for a small radiant staple-up system. I would use plates either the Watts / GrafTech product or the heavier al plates. Then leave a two inch air space then add as much insulation as will fit. If the room is not giant I would bet you could use the DHW de-superheat coil to warm the floor. The more tubing the lower the tempurature required to do the job. I would design that floor for about 85*F incoming water.

    Good luck, and keep us posted.

    If you need more info on the materials either send me a PM or give me a call: 440.233.0840.

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