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View Full Version : Daiken Mulit Split Zone control - help needed







dmann33
04-11-2013, 08:10 PM
My 1st post - I'm dissatisfied with my new Daiken. Any input very much appreciated.


Model: 4MXS32GVJU + 3 indoor units: FDXS09LVJU (x2) + FDXS12LVJU

For most intents the heat and cool operation of this system works great. However, I am not satisfied with how the auto changeover control appears to be working. I am looking for a solution or work around that doesn't involve uninstalling the outdoor unit and replacing it with 3 smaller ones. Yikes$$$

I have the system installed and servicing 3 separate rental units. I expected (and was told) that if all indoor zones were set to "AUTO" that once the zone with priority was satisfied that other zones could get a call in the opposite operation mode (if needed). (i.e. - say all zones in "AUTO" mode. Zone A is heating toward its setpoint (and has priority) while zone B is subsequently turned on with a setpoint that would require cooling. Zone B enters standby mode waiting for Zone A to satisfy. Once satisfied, I would expect Zone B to then get its cooling call (after 3-4 minutes changeover lockout, ofcourse).

HOWEVER, that doesn't seem to be the case. It appears that since Zone A has priority and last ran in heat mode that NO OTHER ZONE will EVER get a cool call satisfied until Zone A EITHER happens to also need a cool call or is turned off. Otherwise, Zone B could wait hours, days or even months to get its cool call satisfied. :mad:


Does that sound right? I can't imagine what the benefit is of this design? It's horrible!

I rec'd conflicting information from Daiken, but the last person I spoke with claims its designed to work this way. Can anyone in the field verify? :confused: If true, has anyone ever tried to set all Zones to have priority? (I wonder if that would work or fry my board).

frank
04-11-2013, 08:17 PM
With any 2 pipe (Mitsi VRF Excepted) you have to have a Mode (Heat/Cool) changeover Master. This can be by indoor unit or outdoor stat/BMS etc.

On a straight forward 4MX, one of the indoor units is designated a Changeover Master. The other indoor units (Slaves) have to follow the Master.

install monkey
04-11-2013, 08:19 PM
yep it sounds right- i know on the outdoor unit you designate 1 indoor unit as a master- this will determine the mode of operation
of your 3 tennants want different modes of operation then u need individual outdoors

frank
04-11-2013, 08:29 PM
if your 3 tennents want different modes of operation then u need individual outdoors
Or a Mini VRV http://www.spaceair.co.uk/product-updates/mini-vrv-systems-the-benefits/156

install monkey
04-11-2013, 08:45 PM
then you'd need to replace the indoors as theyre not compatible- i was offering the cheaper alternative without the dreaded diversity- (poor bugger at the end of the line has no heating as his neighbours are cookin the pot with 32 deg setpoint) and no clunky bc boxes!:p


Or a Mini VRV http://www.spaceair.co.uk/product-updates/mini-vrv-systems-the-benefits/156

dmann33
22-11-2013, 02:11 PM
Hey Guys - Sorry for the delay. Frankly, I had expected an email notifying me of a reply. That didn't happen and I nearly forgot where to find this post. I'm very happy to have your professional perspective. As you know, Mini-splits are only just now beginning to catch on in the US market. I fully embrace the technology, but finding expert advice in the field here locally is still a bit dodgy. In fact, contacted 2 of 3 Daiken "Platinum" dealers in a 3 hour radius and one very nice operator conceded he had not yet installed a MX type system (only VRV), but insists I let him know what I ultimately discover as he'd be thinking twice about installing one in the future if this was the case. The other couldn't even understand my question (kept telling me that I can't run in opposite modes at the same time). No kidding.

Anyway! Thank you both. I'm happy to get affirmation, but dreadfully disappointed in the facts of the matter. I may just have to break down and find a place to install 2 RXS09LVJU and 1 RXS12LVJU. Or, rip it all out and go to a mini VRV.

In either route, I'm still a little concerned about my ducted air handlers being able to keep up with mid summer demand in HOT Georgia. So, I'm kinda leary to invest more money on the system without knowing for sure. The air flow seems sooo low, even though I've checked my static pressures to be right at max Spec (0.04" supply and 0.07 return = .11 total SP).

I wish could easily install wall units - they seem like less worry with better expected performance (no ducts). But I'd really need to install them on an interior 4" thick wall and hope that the mini condensate pumps can pump up and out. Is that realistic application, w/ a 4" wall?

install monkey
22-11-2013, 08:29 PM
condensate pumps can usually pump 6mtr vertical- just make sure the end of the hose is higher than the pump otherwise u will need to fit an anti cyphon valve - to prevent the pump from hiaving to prime itself- runs noisy when 1st installed as it has to disperse air out the pump

aircon50
23-11-2013, 11:42 AM
Condensate pumps - use Aspen. All the ones I have fitted recently have been supplied with an anti-siphon valve in the box. And - when they say they're quiet - they are!!

dmann33
23-11-2013, 04:26 PM
With any 2 pipe (Mitsi VRF Excepted) you have to have a Mode (Heat/Cool) changeover Master. This can be by indoor unit or outdoor stat/BMS etc.

On a straight forward 4MX, one of the indoor units is designated a Changeover Master. The other indoor units (Slaves) have to follow the Master.


1) So in general these 2 pipe systems w/ indoor master the slaves won't changeover even if the master is satisfied..correct?

2) I know of at least 2 types of priority on the 4MX (floating master or designated master via dip switch on outdoor unit. Is there a way to control changeover on a 4MX using a outdoor thermostat or BMS?

install monkey
23-11-2013, 04:41 PM
q1-correct- the master dictates the mode
q2 - no as i know- see the link below for the service manual and look at the piping diagram for the outdoor unit- the lev's just regulate the flow depending on indoor demand
http://www.mediafire.com/view/5p63559f09h405z/4mxs80%20mulitsplit%20service.pdf



1) So in general these 2 pipe systems w/ indoor master the slaves won't changeover even if the master is satisfied..correct?

2) I know of at least 2 types of priority on the 4MX (floating master or designated master via dip switch on outdoor unit. Is there a way to control changeover on a 4MX using a outdoor thermostat or BMS?

dmann33
23-11-2013, 05:56 PM
q1-correct- the master dictates the mode
q2 - no as i know- see the link below for the service manual and look at the piping diagram for the outdoor unit- the lev's just regulate the flow depending on indoor demand
http://www.mediafire.com/view/5p63559f09h405z/4mxs80%20mulitsplit%20service.pdf

Thanks Install Monkey -

I'm probably going to swap to individual outdoor units so that I can achieve complete individual zone control. I really wouldn't mind one zone simply waiting for another to satisfy before changing modes, but that as I understand that won't happen.

My application is like a hotel (dude ranch actually). In this instance I just needed, to replace a zoned traditional forced air heat using mechanical dampers on a Durozone ED-4 panel. In HINDSIGHT, would individual splits be more practical than having installed a VRV system.

1) The VRV system (VRVIII-S most likely) seems pretty complicated just for 3 individual bedrooms. Yes/no?

2) What Daikin systems would be the most practical for this application? (simple user controls are a very important)

3) Don't the Daikin VRVs use BS units rather than a BC box?

4) I have just one indoor coil per zone (room) and all in one attic sapce. How many BS boxes are needed? One multiport? Confused about these BS boxes and quantity, but these boxes could add up quickly ($$).

dmann33
23-11-2013, 06:39 PM
...... to replace a zoned traditional forced air heat using mechanical dampers.....


I meant to say heat PUMP

install monkey
23-11-2013, 07:40 PM
vrvs will be more expensive- bear in mind the outdoor unit will be undersized- so in extreme weather conditions you wont get full output off each indoor- known as diversity
yo already have your piipework run in for single splits- just a matter of extending ouside for each individual outdoor
daikin do a simplified controller for hotel applications- but unless your indoors are cassettes or ducted units- then you will need to buy a krp interface to allow for hard wired controllers

daikins do use individual bs boxes- 1 per unit if you want individual operation of each indoor unit

individual splits would be your cheapest,most practical option- bear in mind if you have an issue on a vrv system - everyone suffers- u have an issue with splits then only 1 room is affected







Thanks Install Monkey -

I'm probably going to swap to individual outdoor units so that I can achieve complete individual zone control. I really wouldn't mind one zone simply waiting for another to satisfy before changing modes, but that as I understand that won't happen.

My application is like a hotel (dude ranch actually). In this instance I just needed, to replace a zoned traditional forced air heat using mechanical dampers on a Durozone ED-4 panel. In HINDSIGHT, would individual splits be more practical than having installed a VRV system.

1) The VRV system (VRVIII-S most likely) seems pretty complicated just for 3 individual bedrooms. Yes/no?

2) What Daikin systems would be the most practical for this application? (simple user controls are a very important)

3) Don't the Daikin VRVs use BS units rather than a BC box?

4) I have just one indoor coil per zone (room) and all in one attic sapce. How many BS boxes are needed? One multiport? Confused about these BS boxes and quantity, but these boxes could add up quickly ($$).