dakin inverter wont stay rampped up!

[tait71]

hi i have been called out to a lovley house with an unico system installed which has a 5kw daikin inverter unit, the problem i have is the inverter wont stay ramped up, it starts fine ramp up but then ramps down and just sits idling away, the air off the unico is only 29c with the room temp at 21c the system uses a ibd conversion board but it still has the original daikin indoor pcb it doesn't have a daikin controller on it but has a heat miser control, what controls the inverter speed? i have rang dainkin tech checked the outdoor probes they are all within range, indoors have all been rep[laced as has the indoor pcb, gas charge has been checked and weighed in, im stuck:(:mad:

[install monkey]

slow the indoor fan down, hook a controller up to it to see what its doing- run it in test mode

[tait71]

if i hook up a diakin controller i have to ditch the ibd controll pcb which controlles the unico fan! i can slow the fan speed right down the problem is the inverter wont stay at a high enough speed to give any heat out

[frank]

it doesn't have a daikin controller on it but has a heat miser control,

If you ask for help, you ought to at least try the solutions put up by the members.

Disconnect all of the 3rd party controls and do as Monkey says. If it runs OK on it's own controller, then you can look at the 3rd party controls as the problem area.

As with any fault, you have to think logically and rule out parts at a time, otherwise you are just guessing.

[install monkey]

the inverter will only ramp up if its operating within its threshold- compressor current, discharge temp
i meant stick a daikin controller on as a temporary measure so you can see if theres any fault codes

[tait71]

Been to site today ditched the ibd control and wired in a dakin control, I just bypassed the unico fan as it was only wired single speed and I ran the system to get a J3 fault discharge probe, contacted tech who me gave me the probe k ohme to c table found the probes all OK( 5c = 50k o) re contacted tech and was advised that the outdoor PCB is not reading the discharge probe and the PCB needs replaced. Thanks for the help guys :-) hope it works :-) as the PCB does not know what temp the discharge is it ramps down to a safe level but keeps the system running.