Daikin VRV 3 pipe changing mode

[VRVIII]

Crumbs we are having so much trouble on that site it's not funny

On another system they have been waiting for a new inverter compressor. That had a U4 error over the weekend. Our guy went to site, played around checking if all indoors had power on etc. Suddenly it came back on.

Back today to start the reclaim and compressor change but were stopped before starting as another system was not heating properly (historical bad airflow design) + they wanted to have another look at the U4 error (no point changing the compressor if it won't run anyway.)

However half way through that one and a worker noticed oil dripping through the ceiling tile another system had split a liq line! So the compressor/investigation never got started.

The change over system faulting was only noted by the engineer who was looking at another system in error. He mentioned it as a problem but the site guy's are saying they haven't had one complaint from that area so it's being left till we can get the rest sorted...

Multi,
It sounds like you’ve had one of those days
At least you didn’t need to dig your way through the snow to get up the street on the way home

U4 errors can be real pain on older installs, especially when it’s an intermittent fault.


You will probably be aware of the most common reasons for a U4;

• Mains power off at indoor/bs/outdoor
• Loose live or neutral connection
• Mains power has been switched off/on but system fails when reinitializing (turn power off/on again and hold down reset button for 10sec)
• Bad connection on F1F2 comms lines
• Mice or rats chewing into comms cables!
• If it’s an R22 KJ outdoor unit the small green interface pcb that f1f2 cable connects to has been known to cause probs (not applicabe for 407c).
• Faulty indoor/bs/outdoor main PCB (never had this with intermittent U4 error tho)
• K series units can be very slow to recognize a U4 error
• U4 errors will auto reset when comms are reestablished

Let me know how it all works out