Results 1 to 7 of 7
  1. #1

    Question

    What is the minimum temp a thermostat should be set at to avoid damage to the HVAC? I've heard of "freezing the compressor" if the temp is too low... help.

    Should the system be turned off when not in use, and what, if any, damage is caused when the system is turned back on?

  2. #2
    Join Date
    Mar 2005
    Location
    burlington county n.j.
    Posts
    9,743
    referring to heating or cooling?

  3. #3
    Join Date
    May 2005
    Posts
    64
    what part of HVAC heating or A/C

  4. #4
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    heating=50- 90F
    cooling=68- 90F

    settings dependent upon your house construction, local outside weather -- having condensation on the walls is BAD.

    one should be able to shut down any unit & have it restart ok at any time. else there are serious equipment | hardware problems

    [Edited by cem-bsee on 10-28-2005 at 10:24 AM]
    harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!

  5. #5
    Join Date
    Jul 2001
    Posts
    3,112
    post your question in one section.

  6. #6
    Join Date
    Jun 2003
    Location
    Florida
    Posts
    9,548
    Originally posted by jbaumgartner
    What is the minimum temp a thermostat should be set at to avoid damage to the HVAC? I've heard of "freezing the compressor" if the temp is too low... help.

    Should the system be turned off when not in use, and what, if any, damage is caused when the system is turned back on?
    This all depends on the system. Some are designed to run in low ambients,they have a outdoor fan motor control. What you want to make sure is the unit is cycling. If it never turns off, eventually it will freeze up, and then your problems begin.I wouldn't set the t-stat below 68, and I'd make sure the unit is cycling. Most people who turn the stat down low have other problems....system malfuntioning,humidity issues. I'm personaaly comfortable around 77 degrees indoors with 45-50% humidity.Turning system off is fine as long as you don't slug the compressor, meaning it starts up on liquid freon.If your system has an accumulator, it will help prevent this.
    If everything was always done "by the book"....the book would never change.

  7. #7
    Join Date
    Oct 2005
    Location
    Fairfax, VA
    Posts
    111
    If the stat is set too low during the day, return air temp will eventually start to drop at night. Low return temp will cause low suction pressure and the evap coil will start to make ice. Once the coil starts to ice up, it gets worse and worse until you get no cooling at all.
    Either put notes on the stats regarding minimum setting, or use setpoint limits by lock or software.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event