LG heat pump problem

[nike123]

All that happens is that the unit wants to achieve 24C instead of the set point of 20C so will go at 100% till it reaches this, then it should wind down like any other system.

And that is exactly how it should behave according to control strategy, and if the dip switch mean that air return sensor is offset by 4K.

Thermatech, thanks for your comments, but how to tell if the system has a fault.

By measuring and recording compressor frequency, return air temperature, time of changes and set point setting in some time while indoor temperature changes from 16°C (or 18°C, depending on lowest possible set temperature) to set temperature + 4K on both indoor units. For that to happen, you need to simulate low and high heat load conditions by forcing some amount of indoors units discharge air to short cycle.

One thing I can advise you is if I set the remote controller to 30C the outdoor unit current drawn is about 500watts higher than if it was maintaining the setpoint. I have just tried this now. So the compressor is not running 100% but it doesnt ramp down any more.

Once again, it cannot ramp down if air return temperature is not higher than it is needed to switch to lower capacity step (and that must be for sum of capacities for both indoor units).

If change in one capacity step is enough to maintain set temperature within 1K than there is no need to ramp down any more. Only if that capacity change doesn't establish 1K temperature control, outdoor unit switch to lower capacity step and etc...

Please, read that text above carefully few times because, that is foundation for understanding of function of control logic. And, it seems, that part is most confusing to you, according to your questions.

P.S. Sorry, if I something misunderstood, because of language.