Daikin FDYQ160KAV1 Outdoor unit, compressor/capacitor failure?

[mcosier]

Hi all,
After a little bit of help diagnosing my issue here. I have the Daikin FDYQ160KAV1 ducted unit.

Symptoms are as follows:
1. Fan is blowing moderately cold air, but no where near as cold as it used to be (insufficient cooling).
2. Outdoor unit on start up: the condensor fan (the two huge fans on the outdoor unit?) operate at a fairly high RPM when it first starts, then it slows right down.
3. At this stage I can hear the compressor starting, the fan gets a little faster. The compressor hums quietly, then it gets a bit louder in intervals of about 5 seconds... the fans seem to also get higher RPM in line with that humming... like its slowly taking off... but then it reaches a point where it just doesnt get any faster - it stays at a very low RPM, its blowing hot air out.

In usual operation (how it used to work), it would "take off" then fans would go full blast and blow a huge amount of hot air out.

Now it feels like its just not reaching that point, it plateaus and stays running slowly.... and inside air from the upstairs indoor unit is blowing only slightly cool air rather than its usual freezing cold air.

The pipes attached to the compressor - one is hot, the other is very cold ( I think this means the compressor is operating).

What I figured was maybe the capacitor in the unit (a 2200uF 420WV nichicon capacitor) might be failing, causing the compressor not to be able to run at its best? It's not a dual capacity, its a single capacitor (two terminals).

Now, I disconnected it alltogether, and it had absolutely zero change.... it did the same thing, operated the same way.

Has me thinking it might simply not be able to get enough juice to fire up fully due to fault in the capacitor?

The capacitor has no signs of bulging.

Any ideas what might cause the issue?

I would replace the capacitor as a check, but they are extremely hard to find here in Australia - so far no luck finding one.

Thanks,
M

[frank]

Your symptoms sound like a shortage of gas.
You describe the normal startup routine, fans, compressor etc., but when the system has lost gas charge, the compressor will hold at 38hz because it's not seeing the expected increase in circuit pressure/temp.
To determine the diagnosis, you would need a frequency clamp on the compressor wire and a manifold gauge attached. Then, a full reclaim of charge and a weight comparison will confirm fully