I have just had a Lennox XP21 (5 ton) heat pump installed with a Lennox 7000 thermostat. The air handler is a CB31-MV 65 equipped with 20 kw lennox electric strips. The thermostat has been set to 2 stages of heat pump and 1 stage backup. After 6 days I have noticed that the low balance has reset itself from -10C to factory default of -4C. This has happened 3 times for no apparent reason. Also there is a random demand for electric back-up heat at all times and temperatures. Sometimes it is 5kw and sometimes 10, 15 or even 20 - this lasts for anywhere from 30 seconds to a minute and then goes off while the heat pump continues to run. As a result, I am using more electrics now than I was was with my older XP15 single stage heat pump. The installer does not seem to have any answers other than monitor it. Are there any suggestions as to what may be the problem and will adjusting the high balance point lower and or changing the stage delay diiferential and timers make any difference? Also would rewiring the elctric backup to come on in 2 stages as per the available thermostat settings make any difference?