Page 2 of 3 FirstFirst 123 LastLast
Results 14 to 26 of 27
  1. #14
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,308
    Quote Originally Posted by Airmechanical View Post
    besides if the coil is not frozen it ain't gonna try to defrost


    .
    Yes it will.
    Time and temp defrost boards don't know weather or not if the coil is frosted. They only know the temp, and the accumilated compressor run time.
    So setting them at 30 minutes they will defrost needed or not every 30 minutes when the OD temp is below the defrost stat/sensors temp.

    Thats why demand defrost was developed, to stop the wasted defrost cycles.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  2. #15
    Join Date
    Dec 2006
    Location
    Middle Tennessee
    Posts
    11,347

    *

    Quote Originally Posted by jeffrey byron View Post
    reversing valve solinoid no problem, also i hope carrier is using scroll compressor no valve problems. scrolls can pump some liquid and get a way with it.
    defrost timer is going to look at defrost thermostat for permission to go into deforst every 30, 50, or 90 min whatever you set it at. 50 min maybe a good place to start at.

    there are no valves in a scroll compressor no-one disputes that

    IMHO any type of compressor will last longer if it is slugging less liquid refrigerant!

    i have demand defrost on my system

    if i needed to make a choice and i lived in canada that biatch would be on 30 min.

    then again i would set up some other type of blower control probably slowing down

    the indoor blower during heat pump operation which would cause a longer interval between defrost and yada yada yada!



    .

  3. #16
    Join Date
    Dec 2006
    Location
    Middle Tennessee
    Posts
    11,347

    *

    Quote Originally Posted by beenthere View Post
    Yes it will.
    Time and temp defrost boards don't know weather or not if the coil is frosted. They only know the temp, and the accumilated compressor run time.
    So setting them at 30 minutes they will defrost needed or not every 30 minutes when the OD temp is below the defrost stat/sensors temp.

    Thats why demand defrost was developed, to stop the wasted defrost cycles.
    that is what i meant to say (sure) no really i did!

    your right, and when the od temp is below freezing on a customers house i want a defrost cycle every 30 minutes

    that will keep the customer nice and warm (and not whinning)


    .

  4. #17
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,308
    Can't speak for other areas, but around here, once its under 20*, 30 minute defrost is needed. They don't frost up as quick, not as much moisture in the air at those lower OD temps.

    I think your area has a bit more humidity then mine.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  5. #18
    Join Date
    Jun 2007
    Location
    The Twilight Zone
    Posts
    2,964
    My new Goodman is set to a 90 minute time-initated defrost. No issues so far with coil freeze-up here in Baltimore.

  6. #19
    Join Date
    Feb 2006
    Location
    Tn.
    Posts
    1,344
    A heat pump in Canada seems like a huge waste of money anyways to me.why not gas?

  7. #20
    Join Date
    Dec 2007
    Posts
    37
    Quote Originally Posted by m-cooling View Post
    A heat pump in Canada seems like a huge waste of money anyways to me.why not gas?
    Well, Canada is not as cold as you seem to think for one thing.

    Moreover, in Quebec, natural gas was introduced only after the 1970's Oil Crisis to provide an alternative to heavy heating oil and is not widespread. Electricity is cheap and plentiful in Quebec and the typical post-1980's residential system is a heat pump with resistance back-up. (Older buildings often have fossil fuel hydronic heat) Electric is also better for the environment as no fossil fuel is used in electrical production here.

    Our two systems are presently set at 90 and are seemingly doing fine. Also to note that the 38SQ has a spine coil, which may be less prone to icing.

  8. #21
    Join Date
    Apr 2005
    Location
    Kingston Ontario Canada
    Posts
    1,213
    Quote Originally Posted by m-cooling View Post
    A heat pump in Canada seems like a huge waste of money anyways to me.why not gas?
    Because, at least where I live over 50% of our hydro is generated by water and the rest by nuclear. I pay 5.000 cents a KWH for the first 600 KWH and then 5.900 KWH for the remainder and usually use about 1000 KWH's per month. That's heating and all electricity use. A bit more in January and February. I also have a gas freestanding stove that suppliments the hydro, too. There is delivery and regulatory charges on the hydro charges, also. All in all, it amounts to about 12.500 cents a KWH. In the province of Quebec hydro is even cheaper as they have more water generated hydro power and that's the cheapest there is. I also concur with kris AMS. It's not as cold here as you might think. FYI, most of the population in Canada is massed at the Canada, USA border. So we have very similar weather conditions as New York and Minesoda, Washington state even Penselvania, New England, Maine etc. You should come up here and visit. It's not all igloos and ice huts. We are very similar to the USA.

    thorton
    _______________________
    Wisdom is knowing what path to take next…
    Integrity is taking it.
    Last edited by thorton; 12-26-2007 at 12:33 PM. Reason: more to add

  9. #22
    Join Date
    Feb 2006
    Location
    Tn.
    Posts
    1,344
    I cant even remember the last year it snowed here. So where I live is quiet different from New York or Minnesota.I agree the climate of Canada would be similar to these places. But not the southern U.S. These are great explanations of the comment I had made./. THANKS

  10. #23
    Join Date
    Dec 2007
    Posts
    37
    Quote Originally Posted by m-cooling View Post
    I cant even remember the last year it snowed here. So where I live is quiet different from New York or Minnesota.I agree the climate of Canada would be similar to these places. But not the southern U.S. These are great explanations of the comment I had made./. THANKS
    Yes, well the Southern US is several 1000km away from Montreal or Toronto - it should be no surprise that the climate is different.

  11. #24
    Join Date
    Apr 2005
    Location
    Kingston Ontario Canada
    Posts
    1,213
    Quote Originally Posted by Airmechanical View Post
    there are no valves in a scroll compressor no-one disputes that

    IMHO any type of compressor will last longer if it is slugging less liquid refrigerant!

    i have demand defrost on my system

    if i needed to make a choice and i lived in canada that biatch would be on 30 min.

    then again i would set up some other type of blower control probably slowing down

    the indoor blower during heat pump operation which would cause a longer interval between defrost and yada yada yada!



    .
    Hi again, Airmechanical! It's interesting that you mentioned slowing down the inside blower during heat pump operation to cause a longer interval between defrost etc. That's exactly what my Carrier 38YZA does. I have a choice in my configuration options called "Enable Super Comfort Heat Mode" that reduces the airflow from the VS fancoil raising leaving air temperature. No exactly what you were referring too, but similar. However, my heat pump is not demand defrost, it's time temp etc, so I still get the defrost at the interval I have chosen on the board (30-50-90 mins) much to my chagrin. Next heat pump with have demand defrost, that's for sure.

    thorton
    __________________
    Tell it like it is and let the chips fall where they may.

  12. #25
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,308
    The slower the ID blower, the more efficiency you give up.
    Your Carrier may have a sensor to bring the blower speed back up if the LL temp gets to x degrees to protect it in mild weather.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  13. #26
    Join Date
    Apr 2005
    Location
    Kingston Ontario Canada
    Posts
    1,213
    Quote Originally Posted by beenthere View Post
    The slower the ID blower, the more efficiency you give up.
    Your Carrier may have a sensor to bring the blower speed back up if the LL temp gets to x degrees to protect it in mild weather.
    Yes, beenthere, I believe it does. It cycles the fan on the condensor in heating mode at mild outdoor temps! Is that what you mean?

    thorton
    ________________________
    Without passion, all the skill in the world won’t lift you above craft.
    Without skill, all the passion in the world will leave you eager, but floundering.
    Combining the two is the essence of creative life.

Page 2 of 3 FirstFirst 123 LastLast

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