I've seen the Zuba operate at -20C and output 43C. I'd say that is pretty amazing. What's more amazing than that is the fact that the defrost runs for only 3 minutes in roughly 6 hours of heating. I have one installed in my house and I've saved around $700 in heating over last year and this winter is much colder.
I wish i was getting any where close to that with my Zuba system. The installers are now on the way back for the third time this week. My Zuba was installed Aug. 2012 worked good for A/C. but my system does not heat at all! outdoor unit freezes up solid to a block of ice, it is not even below 0c yet and my system just circulates air. I thought it was supposed to defrost, if its a block of ice will the suction pressure not be very low, causing low discharge pressure and there for lack of any heat? The pipes coming in to the indoor unit are both cold, to me there is something wrong. Installers twice now have said the system is working.
Third service call last night. The guy changed some wiring on one of the boards. outdoor unit went in to defrost so he thought he had it. BUT it only defrosted for a minute or two just started to melt some of the ice. So it is still a block of ice and I have to use the emergency heat to heat my home. This thing seems like an expensive electric furnace. They tell me they are getting some one from Mitsubishi to come look at it now. Any one have any problems like this, or was I just misinformed about the system and this is how it is supposed to work?
Well the system seems to be working now. The Mitsubishi guy that came walked up to the outdoor unit and within one minute he said yes there is a problem. Went inside and found that the compressor was basically locked in to low speed. He changed over some wires and we tested it. Compressor speed increased and all of a sudden I now have heat. Such a small overlooked item by all the other people and the installers. Glad it is working now, and so far it seems to be working well.