maxcool
08-09-2010, 08:35 PM
Got sent to a job today which consists of 2 Daikin 3 pipe systems RSEY8K7W1 which have 4 internal units ,with 4 bs boxes and 4 seperate controls on each system.
Over the past 2 weeks some builders have been in an revamped the whole office area. Whilst on site they moved all controls to a corner in office by extending control cable.
A U4 fault is present on one system now and will refuse to run. It may be possible that this was present before the work was carried out but the landlord said it was working fine before.
I have power to condenser, power to all 4 indoor units, power to bs boxes and power to each control. As soon as you turn one of the four controls on, it goes into U4 fault with flashing led. The indoor unit fan runs but that is it.
I know that on each bs box and control terminal there should be 16v dc. On the bs box indoor f1 and f2 on board i only get 13v dc and the outdooe f1 and f2 inside bs box i get 15v dc. On the condenser I get 15.4 v dc with or without the wires connected on the condenser pcb.
I have gone through all of the extended cables and all looks fine. I can only access 2 of the 4 bs boxes but the other two i can see have power and cables look to be fine.
I cant seem to find any damaged cables nor does any control cable seem to be next to power cables as such.
I have carried out a full system reset by isolating all power, then turning internal units and bs boxes on, leaving for 10 mins and then turning condenser on and leaving for ten mins before trying to run system up.
This is really playing on my mind as usually i correct U4 faults quick but cant get my head around this one. Any help, ideas or previous experience would be great to try and put my mind at rest.
Thanks in advance...
Over the past 2 weeks some builders have been in an revamped the whole office area. Whilst on site they moved all controls to a corner in office by extending control cable.
A U4 fault is present on one system now and will refuse to run. It may be possible that this was present before the work was carried out but the landlord said it was working fine before.
I have power to condenser, power to all 4 indoor units, power to bs boxes and power to each control. As soon as you turn one of the four controls on, it goes into U4 fault with flashing led. The indoor unit fan runs but that is it.
I know that on each bs box and control terminal there should be 16v dc. On the bs box indoor f1 and f2 on board i only get 13v dc and the outdooe f1 and f2 inside bs box i get 15v dc. On the condenser I get 15.4 v dc with or without the wires connected on the condenser pcb.
I have gone through all of the extended cables and all looks fine. I can only access 2 of the 4 bs boxes but the other two i can see have power and cables look to be fine.
I cant seem to find any damaged cables nor does any control cable seem to be next to power cables as such.
I have carried out a full system reset by isolating all power, then turning internal units and bs boxes on, leaving for 10 mins and then turning condenser on and leaving for ten mins before trying to run system up.
This is really playing on my mind as usually i correct U4 faults quick but cant get my head around this one. Any help, ideas or previous experience would be great to try and put my mind at rest.
Thanks in advance...