Replies

1. Expert Member
   Akos|Mar 09, 2022 07:55pm|#1

   Which climate you are in and how big is your place and what is each zone supplying? Most likely the issue is oversized equipment.

2. 
   John Young|Mar 10, 2022 05:32am|#2

   I believe I am in zone 4. (Brooklyn, NY) The house is a two floor row house of about 1100 sq ft. One large open space on the first floor and three bedrooms on the second floor. The compressor is a 36k unit. The first floor has a head unit of 18k. The two small bed room are 6k and the master bed room is a 12k.unit. I believe the most important factor in this situation is the fact that this is a row house. IE 2/3 of my "exterior" wall area are somebody elses interior wall so I lose minimum heat through them.

1. 
   Aun Safe|Mar 10, 2022 07:18am|#3

   我不是专家，但我会预测专家会告诉您什么：

   Your 3-ton unit is likely 2-3x oversized for your 1100 sq ft space that has limited exterior wall area.

   至于系统本身，请搜索此论坛。当您将多个室内单元与1个室外单元匹配时，室内部门基本上具有零调节能力，并且它们总是在循环一定数量的温暖或冷空气（即使它们设置为关闭）始终流过制冷剂管道（如果ODU打开）。

   So yeah, I hate to say it, but you might have trouble getting a lot of improvement. Sounds like your contractor needs to learn about manual J and needs to take some extra training courses on multi-splits.

1. Expert Member
   彼得·恩格尔|3月10日，2022年11:13 AM|#4

   Yep, Aun nailed it. When any of the heads call for heat, warm refrigerant circulates through all of them. Just the one calling for heat runs the fan, but you will get some convection in the others. Your bedroom heads are probably 10x oversized, so even without the fans running, they're going to warm the rooms. Bad system design.

3. Expert Member
   Akos|Mar 10, 2022 08:09pm|#5

   I would guess your place has at most a one ton heating load. If your outdoor unit is one of the hyper heat ones, it can deliver close to 4 tons of heating in your climate.

   它超出了荒谬的超大号，进入格子领土。

   最重要的是，系统永远无法正常工作。您已经看到供暖的问题，接下来是冷却和去除湿度的问题。由于大量过大和骑自行车，供暖和冷却的运行成本也将比需要高出约50％。

   The bend aid fix for the temperature overshoot is to configure the indoor units to disable the fan once setpoint is reached. This might require a remote temperature sensor or thermostat on some units. You can check the tech note bellow on what applies to your equipment:

   https://web.archive.org/web/20210204174849/https://nonul.mylinkdrive.com/files/Application%20Note%203048%20-%20How%20to%20turn%20the%20indoor%20unit%20fan%20off%20when%20set%20point%20is%20met.pdf

   The proper fix is not simple. You need a proper manual J for your place to figure out your actual heating loads then size equipment from there.

   My guess is that you would end up with either a two zone setup with a 9k wallmount in the living space and a 9k or 12k ducted unit shared for all the bedrooms or the better setup, wallmount and the ducted unit both on their own individual outdoor units.