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mchild
20-10-2009, 08:57 PM
I have a Daikin VRV-S with four indoor FXSQ ducted units. One of my indoor units is stuck in Low fan. I can change the fan speed of the other units both at the controller by using the fan speed button (one BRC controller for entire system) or through Service Mode 44 and selecting the individual units and then setting the fan speed. But nothing I do changes the fan speed for this one unit.

To make sure I do not have a conflict with another setting, I have reviewed each setting in the Local Setting Mode (codes 20 and up so I can see the setting for each individual unit). Each indoor unit has the same settings. I can force the fan on, in High, by using Service Mode 43. I do not have any other known communication issues. Is there a way to re-set the indoor unit so that it will accept the change in fan speed?

superswill
21-10-2009, 01:38 AM
i dont much Daikin but could a dip switch setting be holding it off? I.E the system being set to a higher static pressure by a dip switch

frank
21-10-2009, 09:56 AM
If you have set the fan speed correctly in Service Mode 44 and the group settings are correct then I would suggest that you look at the wiring for the fan to see if it has been set differently to the others on X4A connector.

The wiring diagram is attached for reference.

Also, have you measured the actual voltages going to the fan motor on each fan coil? Are they different?

mchild
21-10-2009, 03:45 PM
If you have set the fan speed correctly in Service Mode 44 and the group settings are correct then I would suggest that you look at the wiring for the fan to see if it has been set differently to the others on X4A connector.

The wiring diagram is attached for reference.

Also, have you measured the actual voltages going to the fan motor on each fan coil? Are they different?


frank,

Thanks for the attachment. Yes, the wiring is the same on all units with medium static setting using X4A. Voltage is also the same on this unit and the nearest next unit.

The reason the problem unit is in Low fan is I set it to that for the cooling season, as I did for one other unit through Service Mode 44. Now that we are back to heating season I need for all units to be in High fan and this one will not change back to High.

Therefore, I have concluded that something has changed with this unit that is causing it to no longer respond to the change setting. It had been in High fan last winter and accepted the change to Low fan at the beginning of this past cooling season. And as I mentioned it will go to High fan it forced on using Service Mode 43.

When in Service Mode 44 the fan speed for this unit is shown as 1 and pushing the fan speed button on the remote controller does not change that to 3 as it does with the other units.

Anything else I should check?

Thank you.

frank
21-10-2009, 07:50 PM
When the fan coil goes into heating mode, the fan stays at LL speed until the coil thermistor senses a rise in temperature, thus preventing cold draughts.

If the coil is getting hot but the fan stays at LL then the coil sensor would appear to be out of calibration, giving the wrong reading to the PCB. Check the resistance of the coil thermistor against the temp/resistance chart.

mchild
21-10-2009, 09:55 PM
When the fan coil goes into heating mode, the fan stays at LL speed until the coil thermistor senses a rise in temperature, thus preventing cold draughts.

If the coil is getting hot but the fan stays at LL then the coil sensor would appear to be out of calibration, giving the wrong reading to the PCB. Check the resistance of the coil thermistor against the temp/resistance chart.


frank,

Again, thank you for your response. The fan coil will only go as high on fan speed as is set for that unit - right? That is the issue here. I can not set the unit to operate at any speed but L, whether by using the remote control fan speed selection button (top right) or by trying to set it through Service Mode 44. When accessing it through Service Mode 44 the speed is shown as 1 and I can not change it to 3. It stays in L no matter what I try.

During operation I can tell it is in L not H and if I select Fan on the remote all the units come on at H except for this one unit and it runs in L. This unit has been this way since setting it to L in Service Mode 44 at the beginning of this past summer.

I have my fan coils set to go off when t'stat is off so the fan coils do not run in LL during t'stst off periods. I have done this because the temp would over run by several degrees since the expansion valve does not fully close when the unit is off on satisfied t'stat.

I don't believe I have a problem with the fan speed in operation other than it is locked in L and will not go up to H. I am fairly certain if I could set the speed to H it would in fact operate step through the fan speeds up to H as it is supposed to and use the hot start operation mode accordingly.

Thank you for your thoughts and if you may have any more I would greatly appreciate hearing them.

frank
22-10-2009, 09:48 PM
Change the PCB with one of the other units and see if the problem transfers as well.

mchild
23-10-2009, 01:57 AM
Change the PCB with one of the other units and see if the problem transfers as well.


I was afraid we might end up here. Thanks for all of your help.

cuongsatc
24-10-2009, 07:34 AM
I have a software of Daikin ( Heat load calculation for general), When i install it happened an error like this " The installation period of validity has elapsed, can not install" Please help me to fix it. thanks a lot everyone.:)