Daikin FDYQ160KAV1 Indoor Fan Motor Failure

Hi all,

We started getting a burning smell from the vents. Indoor Unit is Daikin FDYQ160KAV1.

The motor still ran but there was little to no airflow from the vents - then after 20-30 minutes of operation, the smell would come through the vents... leave it overnight... turn it on again.. same thing, 20-30 minutes, burning smell....

I detached the fan deck and took it out of the roof, found the motor to be completely blackened / same smell came from the motor. There are no signs of failure of the run / start capacitor whatsoever.

I purchased a new fan motor (slightly bigger, 750w(?_, the one in there was 655). I replaced the capacitor as well just to be sure.

I turned it on and it was running very quiet - spinning very well. However there wasn't much of any airflow still - it was like the fan speed was turned right down. I tried changing the field setting (23) code 6 to its max value of 3 (odd, it only has 3 speed settings?). It made no difference at all.

Then low and behold after 30 minutes of being on cool mode, the same smell came back... The motor must be overheating for some reason or something else is causing it to burn out?

Does anyone know what this could possibly be?

I am reluctant to think that its the PCB, given everything else seems to operate fine - could it really be the PCB causing to much voltage to run through the motor and overheat it / burn it out? I cant think of any other component that is independent to the motor itself that would cause this?

The smell itself to be honest, sort of smells like refrigerant as well - I cant be 100% sure of this - but could the issue be at the compressor side, and leaking refrigerant gas into the fan assembly causing the motor to burn out? My thought on this theory is that the air is pushing out of the fan deck so even if this was the case, it should be pushing that gas away from the motor... so this theory is out....

I wanted to know if anyone thinks I should replace the PCB and what they think the chances of it being this would be? The green light on the PCB flashes - but I suspected this to be normal, but maybe its not? Maybe the reason why its running the fan so low is indicator of another issue? Is there any another way to reset the PCB somehow other than turning the isolator off? (Which I have done for > 24 hour periods with no effect).

Thanks,

Matt

Having fitted the incorrect motor for that unit did you modify the motor wiring to suit the change?

On the Fdy ducted units, the small grub screw holding the fan scroll onto the shaft used to come loose leaving the motor turning but the fan scroll 'windmilling'. Result was poor airflow and the motor running with no resistance, pulling excess amps and failing due to overheating.
Similar to what you describe.

Quote:

---

Originally Posted by frank

On the Fdy ducted units, the small grub screw holding the fan scroll onto the shaft used to come loose leaving the motor turning but the fan scroll 'windmilling'. Result was poor airflow and the motor running with no resistance, pulling excess amps and failing due to overheating.
Similar to what you describe.

---

Hi there,

Yeah it's funny you mention this - it however wasn't the original problem as I took the entire fandeck out of the roof and took both fan scrolls off both shafts - the grub screws were very much locked in - no issues there.

The reason it's funny is that when I put the new motor back in, I mistakenly (in the 50degree+ heat) didn't line up the grub screw with the flat area on the shaft on one side and it actually did exactly as you describe... but I fixed it immediately.

I have been doing extensive analysis on the unit and ended up deciding that it might have something to do with one of the relays that feed the speed wires on the motor. My theory was that maybe one of them had welded and left more than one speed open, causing the motor to overheat (trying to run at two speeds simultaneously).

However, after isolating the other relays, and hard-connecting the brown wire (highest speed?) onto (tried two) of the relays, although it managed to run - I had the two problems still: 1. very little airflow out of the vents, and 2. after 20 minutes the motor overheated again - couldnt even touch it, was that hot, putting off a very nasty smell.

So my last attempt was to hard wire the intermediate speed (yellow), in place of the high speed (Brown) onto the relay, feeding it the high speed pcb wire (ie, trick it to turn on the lower speed during high speed operation when it asks of it).

I ran it for 3 hours tonight and it didn't overheat - but its not operating well at all - barely any airflow, just working really terribly.

So back to square one?

I am now starting to think that it might be something causing it to be fed too much current? Maybe the switch terminal that has the neutral (blue) and the live wire into it might be ****ged causing some form of voltage issue? I am supposing the only real way to know would be to hard join the motor neutral and lives directly without the switch, and then hard-connect the brown high speed wire to the control board (pink is the control board wire it SEEMS that outputs for high speed ask). Connect pink and brown, then flick the switch and let the fan run constantly? See if it runs at full speed, and if it overheats??? Thoughts on this?

The PCB board flashes green every second - steadily, I am not sure if this is an issue?
There are no other codes being thrown in the controller.

Lastly, the high static pressure setting.... that board doesnt seem to have the X1M (?) jumper required to hard-switch that to high static pressure mode (to enable high speed fan operation) - so I tried setting the field settings instead... had absolutely no affect on anything. Any ideas around this?

I just want the thing to run at highest speed when called for - dont care for it running at lower speeds, without it frying up.

All the best,

Matt

Quote:

---

Originally Posted by Brian_UK

Having fitted the incorrect motor for that unit did you modify the motor wiring to suit the change?

---

The motor rewinder specialist bridged the violet wire in the wiring harness to join to the grey intermediate speed - this was the only difference / change made.

They are two different motors, however they are both suffering identical symptoms running off the same board and components - too suspicious to think that it's not something in there causing it to happen.

Matt

Attachment 16044
Here you can see the 4 relays (old motor was 4 speed).
Bottom is brown (fast)
middle is grey (intermediate)
top is yellow (violet on the motor - wtf did they change the colors? anyway trust me)
right side is white (slow? Low/low)

Below the right relay is the switch terminal that I am suspecting might have an issue (right above capacitor).

One question I do have though for the savvy techs out there - if one of those relays was fused - by leaving them connected all together (even though I disconnected the output signals to the fan motor speed wires), could that still affect/cause voltage issues? I figured the reds and blacks going into each relay was there to simply operate the relay, not power the motor itself? Just wondering if I should be disconnecting them ENTIRELY instead of just disconnecting the output - though I am not sure the PCB is going to like me disconnecting the inputs into the relay... if those are left open it might throw codes?

Anyhow, just after some ideas on what to try next to a) not get it to burn out and b) make the thing run really fast to push heaps of air through.

Can you confirm that the scroll is turning the correct way? i.e. rotation.

If the capacitor is wired incorrectly, the motor can run 'backwards' - low air flow

Quote:

---

Originally Posted by frank

Can you confirm that the scroll is turning the correct way? i.e. rotation.

If the capacitor is wired incorrectly, the motor can run 'backwards' - low air flow

---

Yeah this is a fair question - I have the grub screw facing outward, so its accessible from the sides.
I have also verified that it's sucking from the intake, not blowing - and I also took images before and after to confirm they're facing the right direction.

I have an update on the situation:
I disconnected all relays, and all switches and hard wired the neutral, and wired the live wire to the brown (fast speed) wire. Turned it on at the breaker, and the fan started (as it should have) and ran at what is supposedly fast speed.

It still over heated....

So all the electronics are now out of the question, it's not the problem.

What I am starting to think now is there is too much static pressure inside the housing - either due to the intake filter needing replacement, OR, more logically, the evaporator/coil being clogged?

I got up there and sprayed the coil and fins down with detergent and water solution in a spray bottle, and gave it a light brushing.

Unfortunately that attempt didnt make any difference and the motor still got hot. Potentially I didnt clean it well enough?

The theory is that there is something blocking the air through that condensor or through the outlet ducts that is a) causing low air output, and b) causing too much pressure on the motor.

I was thinking of removing the top off the fan assembly and let it run in high speed for half an hour with no pressure, to see if it overheated.... at least then i'd know....

Alternatively remove the filter from the intake and do the same thing.... there's a fairly strong amount of air pressure in there pushing out when i half open the lid - id expect most of that pressure to be released through the coil.... is this common?

Matt

The motor relies on the airflow for cooling the windings.
Are you able to measure the running amps and compare the actual to the nameplate?

If your new motor is performing the same as the old one and showing signs of overheating/premature failure with the same airflow problem then a clogged coil is a real possibility.

You can access the coil for inspection by dropping the bottom plate and carefully removing the polystyrene drip pan. Remove the rubber drain plug to allow any condensate to drain first

Does the airflow improve if you disconnect the outlet ducting?

Quote:

---

Originally Posted by frank

The motor relies on the airflow for cooling the windings.
Are you able to measure the running amps and compare the actual to the nameplate?

If your new motor is performing the same as the old one and showing signs of overheating/premature failure with the same airflow problem then a clogged coil is a real possibility.

You can access the coil for inspection by dropping the bottom plate and carefully removing the polystyrene drip pan. Remove the rubber drain plug to allow any condensate to drain first

Does the airflow improve if you disconnect the outlet ducting?

---

I inspected the coils, and gave them a quick squirt with detergent bottle (300ml or so). I cant see any noticble issues with it - it "looked" clean enough - a bit of insulation fluff at the top bracket in there, but nothing significant at all - vacuumed it too - still no real change.

Is there a chance that its still blocked up and needs compressed air, or am I wasting my time there and the detergent and brush should have been enough / should of been an obvious blockage??

I havent tried disconnecting the outlet duct actually - this might be the next test - see how much is actually coming out the other side of the coil - it might be hard to tell though because of how many ducts we have connected to it - its going to "feel" like quite a bit of air, but "how much" air coming out directly past the coil is "enough" is not going to be known by myself - ie did removing the duct fix it or is it just more powerful that close to the motor....

By the way the coil looks like this (attached)
To check for blockages do you need to also check the back of it? Blowing compressed air directly through the front of it should be enough to be 100% sure its cleaned right?

I see where you are getting at with removing the duct though - but its less likely to be a blockage in such a large ducting system right? I thought it might be a failing zone controller thing - but turning that on and off stops and starts the right area (it has 2 zones), without any issues? Id expect at least one side to be not coming on at all or some other areas blocked out always?

Also blocking the second zone doesnt seem to make much of any difference to flow, its still trickling out... they say you should feel it on the ground under the vent - no where NEAR that much is coming out - it barely pushes a piece of a4 paper around its that weak.?

Thank you!

Matt
Attachment 16045

The coil will get clogged on the face that the air enters, i.e. facing the fan outlet.

Looking at the data sheets for the unit, the fan capacitor is rated at 20uf. Have you replaced this when you changed the motor?

Are you able to test the capacitor and fan running current?

Quote:

---

Originally Posted by frank

The coil will get clogged on the face that the air enters, i.e. facing the fan outlet.

Looking at the data sheets for the unit, the fan capacitor is rated at 20uf. Have you replaced this when you changed the motor?

Are you able to test the capacitor and fan running current?

---

Yeah I checked the cap - all good. I spoke to the motor rewinder, and he told me that the motor was put into the case the wrong way - it has a directional arrow, the person i got it off told me it needs to face away from the output, but it turns out it has to face towards the output - so its been running the wrong way and putting too much pressure on itself.

New problem now is that as I was testing it, the pink wire (one of the control board wires for the relay) touched the case when it was live - and it burn out a fuse in the outdoor unit - the one on the board that connects to the indoor. I replaced this.

But now the indoor doesnt fire up at all - I cant get the indoor motor to fire up - the PCB on the indoor seems fine, its flashing its normal green light. This is after plugging everything back in the way it originally was.

Maybe one or all of those relays are in fact dead afterall? Either that or it fried the board? Id expect it to not be flashing green though. After the fuse was put back in the outdoor unit would also not fire up at all either...... I tried setting mode 20 -> 23 field setting groups all to 01 to default, then after a few resets the outdoor fans are firing up and the pipes are condensating and really cold - but no roof fan turning on!!

Could there be some settings that reset on the board when it blew that fuse? Or more likely to be the relays again?

I tried to isolate it down so that the pink wire was on one relay, with the brown wire - and disconnected all others.... but no luck...

I guess I am back to having to run the fan by direct-wiring it from the breaker - it must either be the PCB or the relays at this point... OR configuration???

Not sure how to reset to defaults... maybe the outdoor unit field settings became reset when that fuse blew? How do I factory reset everything?

Matt

See post No. 8 :rolleyes:

Quote:

---

Originally Posted by frank

See post No. 8 :rolleyes:

---

35 degrees ambient temperature, 50deg+ in the roof.... was always going to happen haha.
Thanks for your help.

Unfortunately the PCB is still buggered, or the relays, one or the other... I've just hard wired the motor now and controlling at the breaker (going to be 35-> 40deg all week), and going to pick up a 3 channel AC wireless switch when it cools down a bit, and just control the fan motor manually with a remote control - $20 versus $260 for the pcb and relays.

Oh well, better than the $12k I was quoted to "fix it" by replacing it I guess - I'll take the win.

Thanks again for your support.

Matt

What is the maximum voltage of ceramic capacitors? The same small capacitors like 100 nano
info capasitor: خازن عدسی 10 نانو فاراد