The Dead Horse just won't die

[saintex]

Daikin RZQ42PVJU9 FTQ SKY AIR

Installed october 2014,

unit outdoor deice thermistor goes to -28c immediately on coming out of a de ice cycle in all weather -18c or +10c, indoor EEV goes to 200pls and very little heat comes out of the unit.


The Relief valve was replaced in April, unit appeared to work for a day then initial problem returned.

The outside EEV was replaced and it did appear to be jammed in the closed position.

It was now summertime and the unit appeared to work ok in cooling.

As soon as cool weather returned and heating was requested the initial problem returned, i.e. coil goes to -28c, poor heating and defrost every 30 minutes (no ice present).

Interestingly the unit could be coaxed into working normally by putting it into a cooling cycle via the tStat.
The outdoor coil would only go to 5-8degC cooler than the outdoor temp the indoor unit EEV would range normally from 550-650pls and HOT air would be produced
(by the unit that is, not me).

This would continue until the unit would either cycle off due Tstat setpoint being reached or a REAL defrost with the coil properly iced up after hours of use. Then the machine would return to its old ways until I manually run it through a short cooling cycle.

Daikin REPLACED the RZQ outdoor unit.

The new one does the exact same thing except the cooling cycle trick does not work anymore.

The installer doesn't know and the regional Daikin service guy would not appear to know either...


When it works(ed) it was great but it doesn't work.

How could two machines have the same issues?

The interior FTQ unit?
EMI?
Trafalmadoreans? So it goes


Help

Dave

[saintex]

Anybody want to take the hook?

[nike123]

I would say 4way valve faulty, if that outdoor unit is not replaced.
Maybe one of refrigerant lines is partially kinked! Therefore reduced liquid refrigerant flow.


Interestingly the unit could be coaxed into working normally by putting it into a cooling cycle via the tStat.
The outdoor coil would only go to 5-8degC cooler than the outdoor temp the indoor unit EEV would range normally from 550-650pls and HOT air would be produced
(by the unit that is, not me).

Also, check that indoor unit EEV is fully open in heating (no temperature difference at pipe before and after indoor EEV)!

You should measure pipe temperatures and superheat/subcooling alongside with pipe temperature differences, and that will tell you where is problem!

[Tayters]

Daikin RZQ42PVJU9 FTQ SKY AIR

Installed october 2014, Did it ever work correctly?

unit outdoor deice thermistor goes to -28c immediately on coming out of a de ice cycle in all weather -18c or +10c, indoor EEV goes to 200pls and very little heat comes out of the unit. Is the coil actually at -28*C or is probe reading incorrect? Why defrosting at 10*C? Was it iced up?


The Relief valve was replaced in April, unit appeared to work for a day then initial problem returned.

The outside EEV was replaced and it did appear to be jammed in the closed position. Which EEV. See there are two outside, one for subcooler. One listed for indoor unit which is unusual for a split. Perhaps I'm out of touch or is this part of a larger system?

It was now summertime and the unit appeared to work ok in cooling. 4WV problem as Mr Nike says.

As soon as cool weather returned and heating was requested the initial problem returned, i.e. coil goes to -28c, poor heating and defrost every 30 minutes (no ice present). Again, is coil probe at fault as it shouldn't be defrosting if no ice present.

Interestingly the unit could be coaxed into working normally by putting it into a cooling cycle via the tStat.
The outdoor coil would only go to 5-8degC cooler than the outdoor temp the indoor unit EEV would range normally from 550-650pls and HOT air would be produced
(by the unit that is, not me). Outdoor coil should be hotter than outdoor temp in cooling

This would continue until the unit would either cycle off due Tstat setpoint being reached or a REAL defrost with the coil properly iced up after hours of use. Then the machine would return to its old ways until I manually run it through a short cooling cycle. Moisture getting in coil probe, cooling mode drying it out? Long shot.

Daikin REPLACED the RZQ outdoor unit.

The new one does the exact same thing except the cooling cycle trick does not work anymore.

The installer doesn't know and the regional Daikin service guy would not appear to know either...


When it works(ed) it was great but it doesn't work.

How could two machines have the same issues? Piping issues, moisture, faulty indoor

The interior FTQ unit? Possible but unlikely
EMI? Very much doubt it
Trafalmadoreans? So it goes :cool:


Help

Dave

Some points repeated from previous post but might help.

Thanks,
Andy.

[saintex]

So....the indoor EEV was going to 200pls in heating.

They replaced the indoor coil with the EEV.

Same problem.

They Tried to replace the FTQ motherboard 3 TIMES, every time with the correct adaptor (11k Ohms) it would give the error AJ-01. The same board would do this On my machine and on a new machine.

Today my tech and the regional service manager went into the field and visited 3 RZQ42 and a number of RZQ36 and RZQ24...guess what?

Heads up

all the RZQ42 do the same thing the indoor EEV shuts down to 200pls in heating and the outdoor coil goes to -28. So everyone is using back up heat cuz the machine isn't working and they don't know it.

All the RZQ36/24 work just fine!

Daikin better fix this goat fest or I see a class (RZQ42) action suit in the mix.


I would appreciate if anyone who has installed a RZQ42 could CONFIRM it works, or not.


Thanks

[AlexG]

Refrigerant charge is OK?

[saintex]

Yes
When the indoor coil was replaced the charge was 9 pounds something which is equal to the factory charge plus line length and ftq42 charge.

Thanks for asking

[mikeref]

This thread reminds me of a Vehicle that ran fine. Out of the blue, it simply shut down. Give it half an hour and problem disappeared. Apparently this abrupt shutdown continued at random and Mechanics were all over the engine and electrical systems. Workshop couldn't find anything wrong.
Removal of the fuel tank revealed a plastic bag was randomly plugging fuel flow.

My point? Running this A/C on cooling may be dislodging some foreign matter within the pipes.
Heating mode has this item (s) doing the same thing as the Plastic bag.

I know this theory is a long shot, tho possibly worth considering.
Cheers, Mike.

[saintex]

I hear ya.
The system is REQUESTING the inside eev to 200pls during heating. It may indeed be jammed but the system is nonetheless requesting it.

Intermittently the computer requests normal operation of the eev (500pls) even though it should be 2000pls...