Strange behavior of Daikin VRV indoor unit

[nicolacozma]

Hi all,

This is my first thread on this forum, and I would like to know if someone of you came across with this type of problem.

I have one Daikin VRV outdoor unit (RXYQ10P..) with 12 indoor unit. Two of these indoor unit(always the same) even I have setting the temperature at 16c (with 26c indoor temperature) bouth two EXV-indoor expansion valve are completly closed (0 pulses). With Service Checker attacched, I find out that two indoor unit have the parameter THERMOSTAT_ON set to OFF.

I have check all the indoor temperature sensor (ambient, gas pipe, liquid pipe sensor) for that two indoor unit and everything it's ok, then I have replace the indoor PCB, and I don't obtain positive results.

What it's happend? I don't have seen something like that before.

Many Thanks,
Nicola

[frank]

I have setting the temperature at 16c (with 26c indoor temperature) bouth two EXV-indoor expansion valve are completly closed (0 pulses). With Service Checker attacched, I find out that two indoor unit have the parameter THERMOSTAT_ON set to OFF.
Many Thanks,
Nicola

With the service checker you can force the indoor unit to Thermostat - On. Without this (a call for cooling) the EEV will not pulse open.

[Brian_UK]

Could this be a problem with the remote controller, Frank, not sending an 'ON' signal ?

[nicolacozma]

Hi,

First of all thanks for reply. I have pull-out the motorised valve of EXV and the valve body its ok (it close and open).
Otherwise if I shuttdown the power supply of the system and I wait 15-20 min after that all two unit works wanderful till the day after.

Tomorow I will change the control panel.

Please What I have to do to force the thermostat in ON with service checker, Frank?

Best regards,
Nicola

[frank]

Please What I have to do to force the thermostat in ON with service checker, Frank?

Best regards,
Nicola

Click on the Centralised control tab, select the indoor unit in question, select the mode, adjust the set point to min/max (cooling/heating) an click the Start tab

[nicolacozma]

Hi

I have a good news and I would like to share it with you.

I have find out that even two EXV of two indoor unit are fully closed (0 pulses) praticaly they leaks the refrigerant. This means that liquid pipe temperature get down under 0 degree and the indoor unit go in antifreeze protection this means the thermostat will be set automatically to OFF. I have used an surface thermometer and I have checked the pipe temperature before and after EXV(at 0 pulses).

I have replaced yesterday the two body valves and till know the system works well. Of course to have a full confirmation I have to wait a couple of days.

Thanks all for replys,
Nicola

[woolyback]

If this is any help now, first thing what type of fan coil is it? as i know with the new cassatas once the unit hits set point the unit will then only look at the remote controller thermistor which you cant see on the checker you will have to look at code 41 unit 00 temperature then this will decide thermostat on if this is the case there is a code to stop the unit looking at this thermistor if nes, the only other thing I came across was the small Daikin cassette which had some problem with the expansion valve not closed from the factory properly(as they should only come 2000 pulses only) if you shut the unit off then on about 10 times waiting 3min in-between power on then down this will make sure the valve has closed correctly.

[nicolacozma]

Hi woolyback,

Thanks for reply. The goal of this forum is to share our experience with anybody who read this forum, and you are doing this.

Best regards
Nicola

[Paulgfm]

I have an LC fault code on a RSEY8 10kjy1, Could this mean the Invertor board is US

[frank]

Why not start a new thread Paulgfm, after all, the last post in this thread is nearly 4 years old!! :eek: