Im having a problem with this unit cutting out on high pressure switch...It only does it in heat mode. everything checks out! in cooling it works pefectly fine. pressures,tempatures all good!! as soon as it goes into heat mode, suction stays at 65 psi and high side sky rockets to 400 psi then cuts out on safety..no restrictions in air flow what so ever. indoor/outdoor fans/motors check out.. IM PUZZLED! Any ideas out there???