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  1. #1

    Question Emergency/Auxilliary heat switch on thermosts

    Since both the T8411R (downstairs unit) and the old Trane (upstairs unit) thermostats require manual switching to Emergency Heat, how do I know when to switch over? The guy who installed the thermostat just said to switch over when the temperature stayed below freezing for several days. What happens if I'm not home for a week when it is freezing?
    Never had a heat pump before and recently moved to a 15 year old house with no manuals available for equipment.
    Should I consider switching to programmable thermostats?
    Thanks!

  2. #2
    Join Date
    Jan 2004
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    Programable thermostats require manual switching to emergency heat.

    You switch to emergency heat when the OD unit doesn't work.
    It cost more to use the electric heaters only, then the heat pump with the electric heaters as back up.

    There are a lot of heat pumps in my area. No one switches to emerg heat just because its below 32 outside.
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  3. #3
    Join Date
    Jun 2003
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    Alot of programmable stats have an auxilary heat feature, in which the stat switches on your emergency heat if the heatpump can't keep up with the heat loss of your home. A properly set up thermostat will not only make you more comfortable and protect your home(freezing pipes), it will save you $$$ in energy usage.
    If everything was always done "by the book"....the book would never change.

  4. #4
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    Aug 2003
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    I think you are asking if the system needs to be manually switched to backup (emergency) heat when it gets cold out. If properly wired up the unit will run the heat pump either to a set outdoor t-stat setting or bring on the elements as needed if not keeping up automatically. The only reason you may need to use emergency heat is if there is some kind of problem with the heat pump or you don't want to use the heat pump for some reason. Emergency heat will use the backup heat only which, as has been said, is not cost effective.
    Its a good Life!

  5. #5
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    As previously stated by "been there", emergency heat is used if the heat pump is broken (or if you are tired of hearing it run all day).

    An old mechanical/mercury t-stat will bring on the auxillary electric strips only if the house gets colder with the heat pump running.

    A new digital t-stat will bring on the aux electric strips if it sees that the indoor temp is beginning to go down. Anotherwords, the house doesn't have to get 2 degrees colder for the aux heat to come on.

    Digital programmable thermostats for heat pumps are a great idea for both heating and cooling modes.

  6. #6
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    Quote Originally Posted by smokin68 View Post
    Alot of programmable stats have an auxilary heat feature, in which the stat switches on your emergency heat if the heatpump can't keep up with the heat loss of your home. .
    That would be aux heat, not emergency heat.
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  7. #7
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    Quote Originally Posted by beenthere View Post
    That would be aux heat, not emergency heat.
    One and the same. Jumpers in alot of stats.
    If everything was always done "by the book"....the book would never change.

  8. #8
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    *

    Quote Originally Posted by smokin68 View Post
    One and the same. Jumpers in alot of stats.

    ya but even though its jumpered, in emergency heat the compressor wont run

    so its not one and the same



    .

  9. #9
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    Quote Originally Posted by Airmechanical View Post
    ya but even though its jumpered, in emergency heat the compressor wont run

    so its not one and the same



    .
    Stop. It's the same friggen bank of heat strips. It's the control that's different. You can call it auxilary,second stage,emergency, whatever. Bottom line is to be set up correctly, the electric heat strips shouldn't come on unless the load is too great for the heatpump to handle, i.e. below the balance point of the house. If the heatpump is running and you switch to emergency heat, you're probably worse off unless you have a giant KW heatstrip as a secondary heat source. So it is one and the same heat source.
    If everything was always done "by the book"....the book would never change.

  10. #10
    Join Date
    Mar 2007
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    Quebec, Canada
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    [QUOTE=kwkheat;1703093] The guy who installed the thermostat just said to switch over when the temperature stayed below freezing for several days.

    I'd say it depends where you live and electricity cost. Here electricity is cheap so we set our low balance point to 12F. This will stops HP below 12F and kicks on heat strips only. This prevent compressor to start on extreme cold weather. HP would still be more performant than heat strips but we go for a longer hp life. Remember that not all HP come with an Outdoor temp sensor and if you don't have one installed by your installer then it's probably why he asked you to Switch to EH manually...This ain't customer friendly.

  11. #11
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    Quote Originally Posted by smokin68 View Post
    Stop. It's the same friggen bank of heat strips. It's the control that's different. You can call it auxilary,second stage,emergency, whatever. Bottom line is to be set up correctly

    you stop

    to call it whatever would indicate you dont understand it!

    emergency heat, equals no compressor running

    auxillary heat, equals in addition to heat pump (unless below balance point)

    thats when the fun starts cause when its below the balance point auxillary heat, equals primary heat

    i am sure you understand that smokin, i was just clearing it up for the people who (dont get it)


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