Daikin vrvII Technical help required.

[pip29]

Daikin vrvII mod: REYQ16M8W1B r410a

Can anyone give me the suction presure and discharge pressures when system is on heating with an outside temperature of 2 degrees.

this unit is going on defrost every 1 hr with outside temp of 2 degrees.

[pip29]

Any help would be great as this system is giving me the signs of having insufficient refrigerant with a suction pressure of 60psi on heating and discharge of 390

[Brian_UK]

Some more information on the system as it stands might make answering a bit easier.

Also, a little patience would encourage answers. Remeber this is an international forum and some members may be working or even sleeping right now.

[The Viking]

Hourly defrosts under these conditions should not be seen as a problem.

Pressure readings from VRV/VRF systems are near to useless when it comes to diagnose faults. (Unless you think there is a problem with pressure transducers...)

If you believe there is a problem with the charge then your best option is to reclaim the system and weigh how much there are in it compared with what it should be.

INDICATIONS of lack of charge in VRV/VRF systems might include high discharge temperatures/uneven performance between indoor units/little or no subcooling at indoor units in heat mode. But these types of systems are really good at hiding charge problems until it is way out so the best option is always to reclaim. (or hook it up to a service checker but judging by your question this isn't an option)


Good luck.

[pip29]

the costomer has been complaining thats its defrosting alot and cause the office to cool during the defrost period, i just wanted to know if hourly defrosts was common at this outside temperture of 2.

[VRVIII]

the costomer has been complaining thats its defrosting alot and cause the office to cool during the defrost period, i just wanted to know if hourly defrosts was common at this outside temperture of 2.

If the room temperatures are dropping significantly during a defrost, it could be due to ducted fresh air supply. I would suggest you also check supply air temp entering the rooms/ceiling void/units.

[ktm]

I had exact same problem before with exact same vrv. Look at th3 when unit is running in heat after 25 mins or so if it isn't above 55 then I would definitly recover the charge. It's true pressure don't realy mean much on the vrv because it injects and everthing else to try keep it's self running as best it can. I found the fresh air ducted into back of unit was at ouside temp (4c) exactly what vrvIII said. Wish I had of read this like 6 months ago.