Page 2 of 3 FirstFirst 123 LastLast
Results 14 to 26 of 30
  1. #14
    Join Date
    Jun 2016
    Posts
    27
    Post Likes
    Thread Starter
    Quote Originally Posted by pecmsg View Post
    So wheres the back up heat.

    Heat pumps need something to back them up when they fail!
    We have a 20,000 BTU gas fireplace on the first floor that does a really good job of heating up that entire floor, as well as some of the upstairs. And I have electric radiators on the ready in my attic for the bedrooms. Doesn't that qualify?

  2. #15
    Join Date
    Mar 2016
    Location
    Dayton Oh
    Posts
    2,340
    Post Likes
    Quote Originally Posted by dansminisplits View Post
    We have a 20,000 BTU gas fireplace on the first floor that does a really good job of heating up that entire floor, as well as some of the upstairs. And I have electric radiators on the ready in my attic for the bedrooms. Doesn't that qualify?
    I believe what pec was referring to, is in a typical application, where you have a heat pump with an air handler, you have emergency backup electric heat built into the air handler. So when the heat pump fails your electric heat will still keep the house at a safe temp until a tech can arrive. Please correct me if I'm wrong pec.

    How was the house heated before? Just curious.

  3. #16
    Join Date
    Aug 2002
    Location
    Southold, NY
    Posts
    27,193
    Post Likes
    Quote Originally Posted by jbhenergy View Post
    I believe what pec was referring to, is in a typical application, where you have a heat pump with an air handler, you have emergency backup electric heat built into the air handler. So when the heat pump fails your electric heat will still keep the house at a safe temp until a tech can arrive. Please correct me if I'm wrong pec.

    How was the house heated before? Just curious.
    Your correct.

    Also yes the heat pump can be sized for the heating load But no need to go extreme.

    This Mitisubishi "System" is Too Damn Large!

  4. #17
    Join Date
    Jun 2016
    Posts
    27
    Post Likes
    Thread Starter
    Quote Originally Posted by jbhenergy View Post
    How was the house heated before? Just curious.
    The house was previously heated by a Burham natural gas boiler feeding radiators with forced hot water. This system heated the house with the exception of the three 100 sq. ft. bedrooms. They all had 46" hydronic 240volt baseboard heaters with their own thermostat. Bedrooms were always perfectly comfortable.


    Quote Originally Posted by jbhenergy View Post
    I believe what pec was referring to, is in a typical application, where you have a heat pump with an air handler, you have emergency backup electric heat built into the air handler. So when the heat pump fails your electric heat will still keep the house at a safe temp until a tech can arrive. Please correct me if I'm wrong pec.
    As I'm sure you know, minisplits don't have this capability. The backup heat I have is the gas fireplace, mentioned above, and plug-in portable space heaters.

  5. #18
    Join Date
    Dec 2009
    Location
    maroon lazyboy
    Posts
    2,664
    Post Likes
    Have you tried running only one or two units upstairs, and then turning on unused units units when needed?

  6. Likes Nauger liked this post.
  7. #19
    Join Date
    Jun 2016
    Posts
    27
    Post Likes
    Thread Starter
    Quote Originally Posted by pecmsg View Post
    This Mitisubishi "System" is Too Damn Large!
    So what do you think I should do about it? One consideration is this type of reworking:

    Replace the 9k units in the bedrooms with 6k units, and maybe move the 12k in my basement up to the first floor to replace the 18k there. I could move a 9k from one of the bedrooms to the basement. So it would then be like this:

    Basement: 9k (previously 12k)
    First Floor: 12k (previously 18k)
    3 x bedrooms: 6k (previously 9k)

    Would that make a difference or are you saying the outdoor unit is the problem? What would be your solution to the "System" being "Too Damn Large"?

  8. #20
    Join Date
    Jun 2016
    Posts
    27
    Post Likes
    Thread Starter
    Quote Originally Posted by knave View Post
    Have you tried running only one or two units upstairs, and then turning on unused units units when needed?
    Yes, I have tried this. Running two units is what I'm doing now upstairs. I can pull this off because my daughter is only 5 and her door can be open, and she doesn't really care that her room (with the unit off) is warmer. Some day she'll want that door 100% closed and she will not be OK with higher temps. Even with only two running, the humidity levels are in the high 60% to low, even mid 70% at night. During the day, on a hot day, it does get down to mid to high 50%'s. I did try running only one unit as a test. But the bedrooms are too separate, physically, and I ended up with huge differences in temperatures. It did help with the humidity but it's 100% unworkable, especially at night when doors need to be at least partially closed. Looking the proposed downsizing in the post above, do you think that would help?

  9. #21
    Join Date
    Aug 2001
    Location
    Pavilion, NY
    Posts
    3,486
    Post Likes
    personally thinking,,, the units heat fantastic, the units cool fantastic, the units don't dehumidify to your liking especially in low load conditions. I don't think that making the units any smaller is going to make a significant difference and a unit designed to solely dehumidify is the answer. if your contractor is going to go through a significant expense to rework the system, everyone involved would be better off putting that money towards a system that is designed to do what it is solely designed to do and everyone walks away with a system that will operate.
    ...

  10. Likes Nauger liked this post.
  11. #22
    Join Date
    Jun 2016
    Posts
    27
    Post Likes
    Thread Starter
    Quote Originally Posted by kangaroogod View Post
    personally thinking,,, the units heat fantastic, the units cool fantastic, the units don't dehumidify to your liking especially in low load conditions. I don't think that making the units any smaller is going to make a significant difference and a unit designed to solely dehumidify is the answer. if your contractor is going to go through a significant expense to rework the system, everyone involved would be better off putting that money towards a system that is designed to do what it is solely designed to do and everyone walks away with a system that will operate.
    kangaroogod, are you saying that I should try to get the installer to forget about switching the 9k units for 6k and instead put the money into installing something like the Ultra-Aire 98H? You think that provides essentially the best of all possibilities? It would be nice to have that unit running, with the fresh air intake set up and all.

    Seems like the install cost of the 98H is probably similar to the process of buying the 6k units, pumping down the system, installing all the new units and then vacuuming the system, right? I'd need a duct in each bedroom (x3) and one down to the LR which could then extend through to the basement. These are not insulated ducts, I think. And I have an unused chimney that could accommodate the duct to the LR and then down to the basement.

  12. #23
    Join Date
    Aug 2001
    Location
    Pavilion, NY
    Posts
    3,486
    Post Likes
    that is my thinking. of course I have not seen the home but I am thinking that perhaps you run a properly sized duct from the dehumidifier to the attic and drop a supply in the ceiling of each room. perhaps mount the unit in a closet upstairs with a wall return grill to the hall and duct the supply into the attic? it sounds like the lower level has not been much of a concern to you? If not then focus on the upstairs and be happy
    ...

  13. #24
    Join Date
    Jun 2016
    Posts
    27
    Post Likes
    Thread Starter
    Quote Originally Posted by kangaroogod View Post
    that is my thinking. of course I have not seen the home but I am thinking that perhaps you run a properly sized duct from the dehumidifier to the attic and drop a supply in the ceiling of each room. perhaps mount the unit in a closet upstairs with a wall return grill to the hall and duct the supply into the attic? it sounds like the lower level has not been much of a concern to you? If not then focus on the upstairs and be happy
    The RH level in the living room is lower than upstairs but never below 53% or so and creeps up to mid 60s or so at times. The basement has always been humid in the summer, but that's unrelated. If I'm going to do whole house dehumidification, it seems like it's crazy to keep running my big-box Frigidaire dehumidifier in the basement. My thought was a WHD in the attic with a duct to each bedroom and then down the chimney to the first floor, and basement. Run a return duct to a central spot near the stairs on the second floor.

    Do you pros think this is a reasonable demand on my part? If they sized things properly and did their homework, I wouldn't be in this predicament. I was sold top-of-the-line comfort at a premium price. Swapping out the wall units as per the above post would certainly cost them time and money too. Is this comparable? It does seem like the WHD is far more predictable in results, which is also incredibly important.

  14. #25
    Join Date
    Jun 2016
    Posts
    27
    Post Likes
    Thread Starter
    I've been in touch with another person (who I found on this site) that had a very similar problem with a mini split system. He says that while the WHD would be good, and probably is necessary (although he ended up with multiple dehumidifiers around the house instead of WHD,) he thinks that not addressing the oversizing is asking for problems down the road. Short cycling will take its toll on the system, and the oversized units will lead to over-drying in the winter. Any thoughts on that?

  15. #26
    Join Date
    Aug 2001
    Location
    Pavilion, NY
    Posts
    3,486
    Post Likes
    there is no moisture exchange in the winter.. not sure where over drying would come into play. I respectfully disagree with your comment. I think the best approach is to have a heat loss AND heat gain done on each area the unit serves. you live in a cold climate and Heating design trumps a cooling design.
    ...

Page 2 of 3 FirstFirst 123 LastLast

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Contracting Business
HPAC Engineering
EC&M
CONTRACTOR