Do you happen to know what size bypass you have fitted in this system as it should be pretty big for a system this size?
With a system that size, its large enough to do my whole house at once, they are not designed to be running when you have the total capacity of just a couple of zones on. The system is too big for how you want to use it and the controller canāt control poor installations, oversized or under sized systems.
The system needs to move massive amounts of air, it wants to maintain room temperatures but as it canāt slow down enough it stops and starts.
You either do the following.
Run more the home at once so the system gets to do more work, this is going to increase runtime which you donāt want but limit how much it stops and starts.
Even once the place gets to temperature this could still happen.
You create an automation so that when ever the system reaches setpoints then it is turned off for a period of time. This will reduce running costs and prevent stop starting so much and the only downside to this is that you may have times the place gets cold but you could also set a restart time/temp.
Replacing the system is not really an option due to cost of course but would solve a lot of issues as you can go down a size or more, you can buy systems that will slow down to 5kw or more etc.
Having one or two ducts on as a spill is still too small for this system, it moves so much air you would need to have 4 x 250mm ducts open to relive its air supply/pressure correctly
Thanks for that explanation mate. Itās a pretty big house, so the large system was recommended. But in hindsight it is probably oversized and I shouldāve really looked deeper into the specs of operating range and found a better unit/ brand that was capable (actron?). Maybe if the unit needs replacing eventually this will be the solution.
I think theyāve fitted a 350mm bypass duct.
Interesting about auto vs economy. It seemed to behave a little bit better in economy mode, watching it for a while, it still reverted to Daikin (E) sensor control once the zones reached setpoint. Not sure how this differs from the auto mode but it seemed to be slightly less aggressive in cycling.
I think this will be the best option using HA. It seems to mainly be an issue at night when the temp disparity is large so the return air temp crashes after rising on the bypass air. Iāll try limit it to night hours, and maybe use a 0.5-1 degree/ 30min off time before it can retrigger to turn on again.
Iām not a real fan on the Actrons really, they are alright but I would still prefer a Mitsubishi electric or Panasonic
Over one, Daikin stuff is alright too until you get to 18kw and up and then the minimum capacity gets ridiculous.
A inverter system that operates between 16.8kw - 26.8kw on heating is stupid.
That bypass aināt the best size either, I would be using two of that size on a system that big or a single 450mm.
That too could be part of the problem
350mm I only use on system up to 16kw max
Iām not positive, it could be a 450mm bypass, the damper was quite big and was a squeeze getting it into the ceiling.
I wish Iād seen this thread before building a house haha. It was typical builder process, just get their suppliers to do whatever. Anyway at least itās powerful and can really heat or cool the whole house in free energy hours.
Hey mate,
Did you have your devices in yet for sale or still waiting for them to arrive?
Thanks
Hi mate, I have them here, I just got the stickers for them today.
Iām just revising and double checking all the code and features over the next week and they will be ready to send out.
You can just delete the top-level AirTouch 5 hub and then re-add it. The remaining zones will be recreated with the same unique IDs so automations and dashboards wonāt be affected.
Whatās the best way to identify whether the A/C unit is actually operating or not for automations?
Kind of hard too unless you have a device that reads the power usage or the device Iām selling shows the supply air and return air temperatures and if the system is in cooling heating mode so I use those.
I have a Shelly device in the meter board that has a clamp around the power line, works great. Before that I had an automation that guessed based on temperature changes which kinda worked but wasnāt reliable.
Some heat pumps may have that information available directly, but my 5 year old Daikin ducted doesnāt, the 4 year old Daikin high wall does.
This is the Shelly device I think. Donāt get an inline meter, they can burn out, you want the clamp one. Mine monitors hot water as well.
https://www.smarthome.com.au/product/shelly-em-pro-wi-fi-energy-meter/
Main issue is the cost of an electrician to wire this.
Iāve noticed the unitās constant cycling on/off usually occurs overnight when the zones reach setpoint, and the bypass is open 100%. So I might start by targeting those triggers for automations to switch if off, then turn back on once 0.5-1 degrees lower in the zone(s).
Can you not run the area around where the return air is also so the system isnāt sucking in such cold air?
Maybe for your scenario try seeing what it does on economy, if it behaves basically the same then itās probably and indication that the installer didnāt connect the Daikin controller to the system and change the field settings as required in the installation manual
You could also try adjust the min vent settings to see if you can get away with adding much, I normally wouldnāt go higher than 10% but if you can, the more you have on that can get close to a total of 100% that will stop the bypass opening. Itās fine line though as if you go too high you could start over heating rooms.
I would try 10% on all rooms and if they donāt creep up, try 15%
The logic of the Mitsubishi system is controlling the ramping up of the system, my device helps get rid of these peaks and would stop it going so high when you donāt want it too. I can stop it going over 2kw and maybe a little lower being a 12.5kw
I thought your device was only for 1phase systems?
Nah mate. It will work on single and three phase stuff, itās all the same 
OK tell me more about it
Itās pretty involved really but I have a link to a video about it above. Iām about to make a home assistant dedicated video.