Fujitsu AOY24... ducted question

[Andy_WSM]

Hi All,

Does anyone know if the Fujitsu AOY24 ducted system can be set so that the fan on the indoor unit only runs when the unit is producing heat? - And how can I change it? The room temperature is taken at the controller, so it's not necessary for the fan to run to detect the temperature. I find the fan running creates an uncomfortable draught when the unit isn't heating.

I've had the system for some 4 years now and overall am happy with it, just this issue when heating.

Thanks for your time?

[Andy_WSM]

Oops, I think I mean there is an uncomfortable "draft" not an uncomfortable "draught" :o

[Andy_WSM]

Some googling suggests my unit should have "hot start" but that doesn't appear to be enabled.

Also, some sites suggesting my unit could be in "commercial mode" to allow continuous airflow - how would I disable that?

[glenn1340]

I installed one of these last year but I don`t recall the option you`re after being available ( I`ve not got the manual on me so I can`t back that up). I`d think you`d need the fan running to enable controller to detect an average room temp anyway. Maybe shutting down the vent valves a tad might help.

[Andy_WSM]

I installed one of these last year but I don`t recall the option you`re after being available ( I`ve not got the manual on me so I can`t back that up). I`d think you`d need the fan running to enable controller to detect an average room temp anyway. Maybe shutting down the vent valves a tad might help.

Thanks Glenn, that would be a shame if it doesn't have the feature. All the blurb for the latest Fujitsu units suggest that hot start is standard now - maybe it just wasn't on older models? I don't really want to restrict the flow of air into the rooms as that will impede the units ability to heat & cool too.

[momo]

While I can appreciate the potential discomfort, is the unit being used for ventilation purposes or renewal of air? In this case you should not try to stop it unless you have open windows or other adequate sources of fresh air. (Funny question at this point in the year - isn't the UK hot? or is it to prepare you for the August bank holiday sun!)

[Andy_WSM]

While I can appreciate the potential discomfort, is the unit being used for ventilation purposes or renewal of air? In this case you should not try to stop it unless you have open windows or other adequate sources of fresh air. (Funny question at this point in the year - isn't the UK hot? or is it to prepare you for the August bank holiday sun!)

This is a regular house, with the usual renewal of air facilities, trickle vents in the windows, air brick in the lounge etc, so the flow of air isn't needed for ventilation purposes.

I am preparing ready for the next Autumn / Winter season, which isn't far away now - I found heating with the A/C uncomfortable the previous couple of years, unless I overheated the house, which is unnecessarily costly - and probably not too healthy either.

This time of year the unit is on permanently and having the air circulating through the house is pleasantly cooling - and of course the compressor starts up if the house gets warm. I don't want the pleasantly cooling effect in Winter as you can imagine ;)

Oh, and the UK is rarely "hot". Just 12C this morning and damp out - That's Summer for you ;)

Maybe, as I said above, this model doesn't have the facility, but it certainly seems the case that newer models have "hot start" or "anti draft".

[nike123]

What is full indoor unit model number?

[Andy_WSM]

What is full indoor unit model number?

ARY24LUAN

Thanks.

[Andy_WSM]

I found the service manual and it says there IS a "commercial mode" which ensures the fan always run, but according to the jumpers on my main board it is not enabled - yet my indoor fan always runs in heat mode...

[Andy_WSM]

Just want to give this a quick bump for the weekend on the off chance that an engineer happens by that knows the answer to this?

[back2space]

Hi All,

Does anyone know if the Fujitsu AOY24 ducted system can be set so that the fan on the indoor unit only runs when the unit is producing heat? - And how can I change it? The room temperature is taken at the controller, so it's not necessary for the fan to run to detect the temperature. I find the fan running creates an uncomfortable draught when the unit isn't heating.

I've had the system for some 4 years now and overall am happy with it, just this issue when heating.

Thanks for your time?

Hey Andy!!!

Remember me :)

[Andy_WSM]

Hey Andy!!!

Remember me :)

Richard MSE?

[back2space]

Richard MSE?

Yep thats me! :)

[Andy_WSM]

Hey Andy!!!

Remember me :)


Yep thats me! :)

Ah, it was you that pointed me in the direction of this forum in the first place :)

I've been on this quest to stop the fans when not heating for 4 years, thought I'd have another go ahead of this Winter LOL. I am confident the new grilles will make it "better", but want to cover all bases. I think I am resigned to the fact that this model, for whatever reason, won't do what the manual says it should do - turn the fans off when no heat being provided by compressor. Looks like the house will remain well ventilated / air cleaned. ;)

[back2space]

Ah, it was you that pointed me in the direction of this forum in the first place :)

I've been on this quest to stop the fans when not heating for 4 years, thought I'd have another go ahead of this Winter LOL. I am confident the new grilles will make it "better", but want to cover all bases. I think I am resigned to the fact that this model, for whatever reason, won't do what the manual says it should do - turn the fans off when no heat being provided by compressor. Looks like the house will remain well ventilated / air cleaned. ;)

U may have to make sure you run your fans at low speed if you cannot stop them running.

Our mitsubishi heavy industries ducted sytstem at work does not stop the fans when it reaches temperature only in defrost does it stop the fans, in pre heat the fans are running.

What does the system do during defrost?

[Andy_WSM]

What does the system do during defrost?

It does indeed stop the fans in defrost and also stop & starts the fans when in dehumidify mode, so I know the controller is capable of stopping the fans - i.e. there isn't a stuck relay etc.

[back2space]

It does indeed stop the fans in defrost and also stop & starts the fans when in dehumidify mode, so I know the controller is capable of stopping the fans - i.e. there isn't a stuck relay etc.

Same as the mitsi heavy industries system at work.

Is the controller a digital controller? U sure there isnt a setting on there that can be changed?

[Andy_WSM]

Same as the mitsi heavy industries system at work.

Is the controller a digital controller? U sure there isnt a setting on there that can be changed?

There is a setting on the main board, but it doesn't seem to work! Hence the thread... :(

[nike123]

What sensor is controlling your room temperature. It could be two sensors, one is in indoor unit and one is in wired remote.
If you chose that indoor unit sensor is controlling, than logic in microprocessor could block option of switching off of fan. If you enable that remote control sensor is controlling one, than that option could be enabled.
I am just guessing, but it could be that simple.
Try to set that wired remote sensor is one that controls room temperature and see is that have any influence.
Sensor selection is described in user manual.

[Andy_WSM]

What sensor is controlling your room temperature. It could be two sensors, one is in indoor unit and one is in wired remote.
If you chose that indoor unit sensor is controlling, than logic in microprocessor could block option of switching off of fan. If you enable that remote control sensor is controlling one, than that option could be enabled.
I am just guessing, but it could be that simple.
Try to set that wired remote sensor is one that controls room temperature and see is that have any influence.
Sensor selection is described in user manual.

Thanks for the suggestion Nike. I use the sensor in the wired remote, but just tried the IDU sensor to see if operates the same - and it does.

I can live with it, would just be nice if I could get the fan to shut off when not heating - would save power too I guess!

[Robin]

This is an inverter model,I think. It could be the compressor slows down but does not actually stop! The best test would be to turn the unit off for about half an hour, then turn it on & check when the compressor starts to see if the fan is off until the indoor coil gets hot ( this only works in heat mode).

[Andy_WSM]

This is an inverter model,I think. It could be the compressor slows down but does not actually stop! The best test would be to turn the unit off for about half an hour, then turn it on & check when the compressor starts to see if the fan is off until the indoor coil gets hot ( this only works in heat mode).

Hi Robin, Tried that. Also tried setting the thermostat right down to 16C and leaving it alone - the IDU fan still runs.

[bigor_2]

At me the following idea:
1. take the external thermostat (any manufacturer)
2. connect it to CN114 (external input: on/off unit) on indoor unit PCB
3. external thermostat will on/off unit (unit will hot start in heating mode)

[Andy_WSM]

At me the following idea:
1. take the external thermostat (any manufacturer)
2. connect it to CN114 (external input: on/off unit) on indoor unit PCB
3. external thermostat will on/off unit (unit will hot start in heating mode)

Ah, now that's a new approach. I'll give it a go possibly later today - just checked the wiring diagram for the board and it looks to be only a signal voltage (i.e. close to ground?) so no heavy power switching?

Thank you for the suggestion - I'll report back on how it's gone!

[bigor_2]

It only idea which needs to be checked up experiment.
Look the electric diagramme.

http://rapidshare.com/files/410724186/page_from__ARH_18-24_LUA.pdf

[Andy_WSM]

It only idea which needs to be checked up experiment.
Look the electric diagramme.

http://rapidshare.com/files/410724186/page_from__ARH_18-24_LUA.pdf

Had a muck around earlier and shorting CN114 makes no difference to the operation when it's either in standby or running - however, say having a cuppa now and wondering if DIP switch SW2-2 needs closing - it is marked as "Ex.Signal function" - but doesn't say what that actually does.

Likewise (see previous post) JP3 is marked as "Fan delay change (heating operation)" and doesn't seem to make any difference either! To me, this is the one setting that I needed to adjust!!!

I'm a it perplexed that changing jumpers & switch settings doesn't seem to change the operation of the unit in any way - it's all rather odd!

[nike123]

Had a muck around earlier and shorting CN114 makes no difference to the operation when it's either in standby or running - however, say having a cuppa now and wondering if DIP switch SW2-2 needs closing - it is marked as "Ex.Signal function" - but doesn't say what that actually does.

Likewise (see previous post) JP3 is marked as "Fan delay change (heating operation)" and doesn't seem to make any difference either! To me, this is the one setting that I needed to adjust!!!

I'm a it perplexed that changing jumpers & switch settings doesn't seem to change the operation of the unit in any way - it's all rather odd!


Fujitsu is organized as military. Why don't you contact your supplier with your problem. I am sure that they will come with some logical explanation or solution.

[bigor_2]

If to look at my file it is necessary to pay attention to absence of communication between CN106 (black on power supply PCB) and CN5 (black on main PCB). It is necessary to connect them pin to pin.

[Andy_WSM]

If to look at my file it is necessary to pay attention to absence of communication between CN106 (black on power supply PCB) and CN5 (black on main PCB). It is necessary to connect them pin to pin.

Ah yes, can see that now - had missed that there was no jumper in place between the 2. Will try connecting them and give it another go. Thanks :)

[Andy_WSM]

Fujitsu is organized as military. Why don't you contact your supplier with your problem. I am sure that they will come with some logical explanation or solution.

It's a few years old now, so not covered by the supplier & I didn't want to start incurring costs for something I am happy enough to play with myself. I have worked to component level on PCBs for years, so this isn't anything particularly new to me, just unknown :D

Not sure Fujitsu would deal directly with a consumer?

[Andy_WSM]

A big thanks to BIGOR_2. :) With his pointing me in the right direction (see above) I have soldered jumpers between the main PCB & the IDU PCB and connected a wireless thermostat up to the IDU PCB and now the unit switches on & off heat mode depending upon the setting of the wireless thermostat. This is a great solution for me - it means the unit doesn't blow cold air around the house when it isn't heating, I've not interfered with it's power connection to maintain heat in the compressor during cold weather or it's ability to carry out defrost cycles etc.

This should prove much more efficient at heating this Winter - the cost of not constantly running the IDU fan alone (at 120W/h) will amount up over the 4 or 5 months the unit is in heat mode.

I had the wireless stat in the garage unused, so it's cost me nothing to come up with a great working solution.

Thanks again BIGOR_2 :)

[back2space]

A big thanks to BIGOR_2. :) With his pointing me in the right direction (see above) I have soldered jumpers between the main PCB & the IDU PCB and connected a wireless thermostat up to the IDU PCB and now the unit switches on & off heat mode depending upon the setting of the wireless thermostat. This is a great solution for me - it means the unit doesn't blow cold air around the house when it isn't heating, I've not interfered with it's power connection to maintain heat in the compressor during cold weather or it's ability to carry out defrost cycles etc.

This should prove much more efficient at heating this Winter - the cost of not constantly running the IDU fan alone (at 120W/h) will amount up over the 4 or 5 months the unit is in heat mode.

I had the wireless stat in the garage unused, so it's cost me nothing to come up with a great working solution.

Thanks again BIGOR_2 :)

Great stuff... Told you this forum was the best :)

[bigor_2]

I glad to help you! Together We Force!

[Andy_WSM]

A big thanks to BIGOR_2. :) With his pointing me in the right direction (see above) I have soldered jumpers between the main PCB & the IDU PCB and connected a wireless thermostat up to the IDU PCB and now the unit switches on & off heat mode depending upon the setting of the wireless thermostat. This is a great solution for me - it means the unit doesn't blow cold air around the house when it isn't heating, I've not interfered with it's power connection to maintain heat in the compressor during cold weather or it's ability to carry out defrost cycles etc.

This should prove much more efficient at heating this Winter - the cost of not constantly running the IDU fan alone (at 120W/h) will amount up over the 4 or 5 months the unit is in heat mode.

I had the wireless stat in the garage unused, so it's cost me nothing to come up with a great working solution.

Thanks again BIGOR_2 :)

This worked an absolute treat this morning. Overnight temps are getting into single digits here now so the A/C was needed in heat mode for the first couple of hours of the day and the modification worked just lovely.

Middle of the day now and I'm back in cooling mode!

[back2space]

This worked an absolute treat this morning. Overnight temps are getting into single digits here now so the A/C was needed in heat mode for the first couple of hours of the day and the modification worked just lovely.

Middle of the day now and I'm back in cooling mode!

ive just returned from camping so been freezing all weekend! I know how cold it is on a night time now!

[RSTC]

Hi, I know this is not the point of the question, but where is your return air coming from? Is it from the attic space? You should be returning from the conditioned room
i.e. the supply air temp = room air temp (when stat is satisfied)

[Andy_WSM]

Hi, I know this is not the point of the question, but where is your return air coming from? Is it from the attic space?

No.


You should be returning from the conditioned room
i.e. the supply air temp = room air temp (when stat is satisfied)

It is :)

[RSTC]

...interesting. Seems alot of work for a simple thing.

What kind of grills are you using? If you are using a single deflection or pressed steel grill it's very difficult to get a satisfactory air distribution in both summer and winter.

[Andy_WSM]

If you are using a single deflection or pressed steel grill it's very difficult to get a satisfactory air distribution in both summer and winter.

Hence the modification to kill the fans when the compressor isn't running and the unit is in heat mode.

It might have been a lot of work, but it's perfect now - and a lot cheaper to run too!

[RSTC]

...All's well...etc!

[back2space]

Hence the modification to kill the fans when the compressor isn't running and the unit is in heat mode.

It might have been a lot of work, but it's perfect now - and a lot cheaper to run too!

Hows the system running Andy now that outside temps have taken a dip? What kind of air off do you get from your vents?

[Andy_WSM]

Hows the system running Andy now that outside temps have taken a dip? What kind of air off do you get from your vents?

Seems to be working very well so far. Temp outside this morning is 5C and the indoor set temp of 22C was reached in about an hour this morning. System is happily cycling on & off. Very crude "air off" measurement of 43C. I have no idea if that is good or bad? - I don't even know that the invertor was calling for the compressor to run at 100%?

[back2space]

Seems to be working very well so far. Temp outside this morning is 5C and the indoor set temp of 22C was reached in about an hour this morning. System is happily cycling on & off. Very crude "air off" measurement of 43C. I have no idea if that is good or bad? - I don't even know that the invertor was calling for the compressor to run at 100%?

43c is good when mine is ramped right up i.e if theres a 3C room difference I get air off of 45-47C but because it is oversized it usually cylces off before it gets any cooler air off.

[Andy_WSM]

Now I'm more awake I can hear the compressor ramping up & down so it's doing it's job lovely this morning. Will be interesting to see how the running costs are. Will post another screen shot in the MSE thread towards the end of the month.

[back2space]

Excellent... ive still got the ongoing saga wiith my multi split... see here

http://www.refrigeration-engineer.com/forums/showthread.php?t=27723

I will never have a multisplit again... far too much to go wrong... however if the problem is as the engineer suggests then it isnt the units fault at all and was the original plonkers who installed the system!

For what I saved at the time getting it done cheaper (I got them some work trhough my company) I have probably spent on the many engineers who have attended but not diagnosed the issue.

[Andy_WSM]

It was down to near freezing outside during the night. The unit came on this morning and was working lovely right up until the power went out. Grrrrr! I hope we're not in for another Winter of power cuts every time the demand gets a bit higher than normal.

Curiously when the power came back on the Fujitsu had changed itself from heat mode to automatic mode, but the clock setting stayed correct. Bit odd. Can't work out why that is.

[back2space]

Could be by default so that it changes to automatic mode incase the room temp has increased above the set temp and the room might need cooling.

[bigor_2]

no comment

[back2space]

no comment

Hi Bigor

The issue isnt with the unit automatically turning back on after power interuption but the unit switches into Auto mode as apposed to heating mode which was the last known operation.

[bigor_2]

Yes.
Unit will always be start in AUTO mode if is not active Auto-Restart because the unit runs on an external thermostat.

[back2space]

What air off temps you getting in heating now?