daikin vrv2 indoor units on PIR sensors/timers

evening all

got a head-scratcher,recently got sent to a job,my first attendance,found REYQ14M,8 indoor units,all cassettes,condenser on roof,2 units in basement,4 in offices,2 in cashiers,served by bsvq100's) and was told to replace LP sensor,found sensor ok! hooked up my lines!nada..system had nothing in it,0 gauge pressure! factory charge,10.5kgs.

found the problem,replaced faulty EEV body,and motor coil as that was blown!vac'd and re-charged accordingly,ran up sweet,job done.

but when checking indoor units noticed 4 out of the 8 fcu's are positioned in offices and come on when someone enters the room on PIR ceiling sensors which also shuts the units off when there is no movement or occupancy meaning the rooms never reach setpoint and the units are constantly turning on and off and as its a financial institution there's alot of traffic in and out of said offices,all day everyday.

has anyone ever come across this and could it be damaging the inverter and comp or wreaking havoc with pressures and temps?

the outdoor fan never really steps up fully,just slow idle for 10 mins then off?same with the inverter comp also idling over,not stepping up?
indoor temps are next to nothing?even on the other units(not on the sensors)

any help would be much appreciated

ta

the 10kg is factory charge- u have to measure the piperun and calculate the total system charge
if they are using a pir to start and stop units then they should be wired via the t1 t2 termials, not switchin the power supply
when u pressure tested and vacced system did you drive open the valves?

ez monkey..
valves open,charge calculated,tested to 35bar/400psi,18 hours no drop,vacd to 2...17.2kgs,charged in liquid line..closed valves.
surely when they start stopping the compressor follows suit,in steps of course?

valves opened via setting mode 2 on the push buttons on the outdoor
http://www.mediafire.com/download/h6...m219-41969.pdf

The turning on and off as people enter the room can be controlled by a PIR connected to the T1 T2 terminals on the indoor units, as long as this has been enabled.

If it's a problem because the unit does not cycle long enough, you could add a run on timer to the PIR circuit, causing the system to run for a minimum 30 minutes etc.

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Originally Posted by 2TORR

evening all

got a head-scratcher,recently got sent to a job,my first attendance,found REYQ14M,8 indoor units,all cassettes,condenser on roof,2 units in basement,4 in offices,2 in cashiers,served by bsvq100's) and was told to replace LP sensor,found sensor ok! hooked up my lines!nada..system had nothing in it,0 gauge pressure! factory charge,10.5kgs.

found the problem,replaced faulty EEV body,and motor coil as that was blown!vac'd and re-charged accordingly,ran up sweet,job done.

but when checking indoor units noticed 4 out of the 8 fcu's are positioned in offices and come on when someone enters the room on PIR ceiling sensors which also shuts the units off when there is no movement or occupancy meaning the rooms never reach setpoint and the units are constantly turning on and off and as its a financial institution there's alot of traffic in and out of said offices,all day everyday.

has anyone ever come across this and could it be damaging the inverter and comp or wreaking havoc with pressures and temps?

the outdoor fan never really steps up fully,just slow idle for 10 mins then off?same with the inverter comp also idling over,not stepping up?
indoor temps are next to nothing?even on the other units(not on the sensors)

any help would be much appreciated

ta

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In this case the PIR sensors must be through the T1 - T2 terminals otherwise if they were wired via indoor mains the system would continually have communication faults. PIR sensors through the T1 - T2 terminals is just like switching the unit ON or OFF at the local control so has no adverse effect on the system.

Operate a test run and after you've completed this check each indoor unit has cooling mode selected and then operate forced thermostat ON from outdoor unit. (Setting mode 2 (Push and hold MODE for over 5 secs) binary 6 (SET 6 times) and RETURN, SET, RETURN, RETURN. Then after around 30 minutes check suction pressure, head pressure, check what compressors are operating INV, STD1, STD2, then check your air off, air on indoors. Something doesn't sound quite right if you operate just the four indoor units without the PIR's and they don't get acceptabe air off, air on. The VRV system has numerous safety devices to protect itself when pressures/temperatures and flow of refrigerant becomes abnormal so as long as you've carried out your job correctly with regards refrigerant recovery mode, pressure testing, evacuating and re-charging the correct amount then you've nothing to worry about. If this is the case then you might have an expanion valve faulty, solenoid coil or thermistor out of calibration but to identifiy this it'd probably be wiser to get a checker on the system. Good luck!