Daikin Fan Fault

[aza]

Hi Guys, visited a Daikin ZMX52HV!NB with fan continuosly running on the outdoor unit when the indoor units switched off (split system).
Checked Gas ok. System runs in heating mode but not in cooling mode. System runs in forced cooling ok. Any ideas???

Thanks

[Temprite]

Not familiar with exact model number but from memory similar unit in Australia 4MX80HVEA had 240 condenser fan motor with two relays one for high speed and one for low speed.

Possible cause for your problem, contacts welded on high or low speed relays on PCB.

Is that a multi split unit?

[paul_h]

Comon here with small panasonic splits. Some panasonics have a dumb out door unit, all controls are in the indoor unit.
What happens with the panasonics here is that in order to fit everything in the indoor PCB and make it quieter, they started using a tiny solid state relay which sometimes fails.
edit: although if you've got a bigger system maybe the fan control is in the outdoor unit and repairable.
You need to find out what relay powers the fan, cut power to the unit and check the n/o contacts for fan switching, if you have a circuit, then the relay is fried because you shouldn't have a circuit when the power is off..

[aza]

Thanks Guys,

Found problem welded relay on PCB

[Daikin=Overated]

There were known problems with a batch of Daikin outdoor condensor fan motors, where by the protective seals failed and allowed water ingress causing a dead short, however that tended to blow the PC boards to bits. Glad you found the problem just thought I'd mention this as we're on topic.