Panasonic Cassette

[rude]

Hi guiys i have a problem with a panasonic cassette Indoor - CS-F50DB4E5
Outdoor - CU-B50DBE8

Now what happens is after 10 mins of running the unit shuts down the compressor and outdoor fans as if it was cycling off. Problem was return air was at 19 degrees and i had it set at 16. So i held the air on sensor to heat it up and nothing unit would not cut back in. So i turned the unit off and back on at the remote and unit kicked in.

I spoke to service center and they said may be a thermistor problem. I have previously installed new PC Boards to indoor and outdoor unit have i done something wrong? There is no wall controller only remote so i can only go by fault code LED on the outdoor unit.

Here are my temp readings.
Indoor on High Fan speed - Air ON - 19 degrees
Air Off - 5-7 degrees
Suction pressure was about 750kpa on R410a

Condensor Outdoor fans appeared to be on high fan.
Air On - 30.5 degrees
Air off - 23.5 degrees

Compressor Amp draw was 8.2 amps on all 3 phases.

Thanks

[nike123]

Check this Panasonic troubleshooting guide!

[nike123]

I have previously installed new PC Boards to indoor and outdoor unit have i done something wrong?

If error is occurred after that, than you probably done something wrong.

[rude]

Well what oringinally happened was i was getting a coms error. Turned out to be the interconnection cable. So i changed the boards and then changed the cable. It did say to run a test mode on cooling for more than 5 mins then switch off to allow heating to run.

Its a strange fault. Maby i should run the cooling test for longer than 10mins and see what happens.

[nike123]

Well what oringinally happened was i was getting a coms error. Turned out to be the interconnection cable. So i changed the boards and then changed the cable.

I taught that we should first check cables and then change boards.

[rude]

haha i was 1 step ahead of you

[nike123]

http://www.nodevice.com/manual/newmans/panasonic2/mac0509061c2pdf/get55293.html

[rude]

I have to pay to access that. Ill get a service manual tommorow at work. I usually fix these things with some success but this ones a strange one.

[al]

Panasonic will not cool below 19, run it in test mode to check pressures etc., temps look fine to me.

al

[rude]

Panasonic will not cool below 19, run it in test mode to check pressures etc., temps look fine to me.

al

i have ran it in test mode and all pressure were fine from what i could see. But i only ran it for 10mins. Im sure the ac is capable to run below 19? It says no where in the manual that it cant. It specifys a temperture setting of 16-31.

I think what im going to do is change the sensors. But before i do that run the test mode for say 15-20 mins, because as i see in test mode it would by pass any set points? So if it does run id say it would be a sensor issue. I hope im right.

[paul_h]

I would have run it in test mode if possible to see whether it's cutting out on percieved temp or due to another reason.
I was going to suggest that yesterday, but because I don't remember much about pana cassettes, I thought I'd leave it for someone like stefscruiser to comment on, or the official tech suport guys that you could use. The last pana cassettes I saw were around the corner from you, next to the TAB office on hassler rd, and that was over two years ago.

As far as pana not cooling below 19C, it may be the case with casettes, I don't know. But I know most of their remotes go down to 16C, it would seem strange if they would only cool to 19C, when the other brands that can only go down to 18C, can manage 18C.
But anyway, I wouldn't be changing any more parts until you can talk to stef or whoever is their tech support on the phone.

edit: I forgot, I have an old ducted pana doing the same thing. Some old lady says the house gets warm, she turns it off and then on again at the controller and it fires up again. I've checked everything and it seems oK, and of course it all works perfect when I'm there, no fault codes, no dodgey readings. Of course I don't want to spend too much time there and charge this old lady heaps of money sitting around waiting for it to fault, and they aren't too good at keep records or remembering exactly was was happening at the time or noticing when it stops until an hour later. But it sounds like a similar fault, although this unit will run for days without stopping, not minutes like yours. But both need to be turned off then on again to fire it back up.

[nike123]

Service manuals are here:

http://www.turnerengineering.com.au/service-manuals.asp

[nike123]

.............................

[rude]

I would have run it in test mode if possible to see whether it's cutting out on percieved temp or due to another reason.
I was going to suggest that yesterday, but because I don't remember much about pana cassettes, I thought I'd leave it for someone like stefscruiser to comment on, or the official tech suport guys that you could use. The last pana cassettes I saw were around the corner from you, next to the TAB office on hassler rd, and that was over two years ago.

As far as pana not cooling below 19C, it may be the case with casettes, I don't know. But I know most of their remotes go down to 16C, it would seem strange if they would only cool to 19C, when the other brands that can only go down to 18C, can manage 18C.
But anyway, I wouldn't be changing any more parts until you can talk to stef or whoever is their tech support on the phone.

edit: I forgot, I have an old ducted pana doing the same thing. Some old lady says the house gets warm, she turns it off and then on again at the controller and it fires up again. I've checked everything and it seems oK, and of course it all works perfect when I'm there, no fault codes, no dodgey readings. Of course I don't want to spend too much time there and charge this old lady heaps of money sitting around waiting for it to fault, and they aren't too good at keep records or remembering exactly was was happening at the time or noticing when it stops until an hour later. But it sounds like a similar fault, although this unit will run for days without stopping, not minutes like yours. But both need to be turned off then on again to fire it back up.

I did speak to tech support as was told it may be cutting out on a low coil temp. But i know the gas charge is correct because i weighed it in. The only other thing they said maby a sensor was dodgy. Problem is the unit doesnt have a wired remote control so it doesnt display any codes. All i have is a remote with no check function. Ill see if these new sensors do anything, if they dont work ill have to sort it out with tech support. Just thought someone on here might have come accross it.

[al]

all brands i've seen have set point of 16, none cool below 18/19, rather than changing sensors why not order a controller? shouldn't be too expensive and can be used on all such systems? if no leds are flashing then the unit doesn't appear to be seeing a fault?

al

[nike123]

After studying service manual for a while, I would also say that frost prevention control is acting and that you should check indoor heat exchanger thermistor for proper value against actual coil temperature before doing anything else.
Test function will probably not override that function.

Remove thermistor from PCB and put it in water-ice mixture. It should have 67,3KOhm +-5% resistance.
If that is OK than PCB is faulty or connection to PCB has cold solder/bad contact.
Are you sure that thermistors are not interchanged when you changed PCB's?
They have similar values and unit may not see that as abnormal thermistor value.

[rude]

After studying service manual for a while, I would also say that frost prevention control is acting and that you should check indoor heat exchanger thermistor for proper value against actual coil temperature before doing anything else.
Test function will probably not override that function.

Remove thermistor from PCB and put it in water-ice mixture. It should have 67,3KOhm +-5% resistance.
If that is OK than PCB is faulty or connection to PCB has cold solder/bad contact.
Are you sure that thermistors are not interchanged when you changed PCB's?
They have similar values and unit may not see that as abnormal thermistor value.

I did check that they were plugged into the correct sockets on the board. I will check the resistance of sensors and go from there. i have ordered the new ones so i can check between the new and the old ones for any differance.

[Devsan]

when changing the boards its always a good idea to change the probes aswell. most faults lie with the probes and not the boards anyway

[stefs_cruiser]

only remote so i can only go by fault code LED on the outdoor unit.

Is the unit displaying any faults? the outdoor PCB will indicate this with LED's

If not, than the micro must think that everything is perfectly normal.
Not quite sure why anybody would want a temp lower than 19 degrees C, but I would be checking the RA sensor.

Where are you measuring the room temp, is it possible that some air is being deflected back into the unit? Sometimes it is good to cable tie your digitemp sensor with the RA sensor, to get a clearer idea.

[amitsaxena]

Dear Check for the sensor which is controlling the Compressor cycling as i feel it is misplaced as there is no problem with your unit.
thanks
amit

[Below 0]

Check indoor coil for blockage, had something similar to this awhile back and coil was choked up. Anti freeze protection stopped unit for 45 mins at a time.Cleaned coil and now all good.

[nike123]

Check indoor coil for blockage, had something similar to this awhile back and coil was choked up. Anti freeze protection stopped unit for 45 mins at a time.Cleaned coil and now all good.

Isn't then dT at indoor coil would be higher than 12-14K?

[rude]

Is the unit displaying any faults? the outdoor PCB will indicate this with LED's

If not, than the micro must think that everything is perfectly normal.
Not quite sure why anybody would want a temp lower than 19 degrees C, but I would be checking the RA sensor.

Where are you measuring the room temp, is it possible that some air is being deflected back into the unit? Sometimes it is good to cable tie your digitemp sensor with the RA sensor, to get a clearer idea.

I did tie the digitemp to the plastic to get the RA. I only had it running on 16 to test. They had it set on 22 but felt no cooling on a hot day.

ive been on holidays for a week so hopefully ill get back out there some time this week.

[rude]

OK bit of an update. Changed all sensors indoor and outdoor. Problem still occured. So i tested on heating and the unit ran for 20mins with no faults.

But on cooling wouldnt run for any more than 10mins. So i decided to put in the old indoor pc board that i had previously replaced and ran the unit and it started working!!!

So i really have no idea why or how it fixed itself but it did.

thanx for all your suggestions.

[stefs_cruiser]

I am still intrigued as to what temperature the end user wants to run it on?
and did it fault at those settings?

Would you mind telling me the customers normall settings please?

[rude]

Customers normal settings was 22 degrees

and yes they first noticed it wasnt cooling set at that temp, so naturally tried to lower the set point and unit would still not cut in.