Mitsubishi MSZ-GL question

[sierradmax]

I purchased a 18,000 BTU Mitsubishi mini-split for my detached 30x30 garage. Installed in September so now, I've been using it for heating whenever I'm occupying the garage. I performed the physical install and I hired a HVAC tech. perform the line-set evacuation and then I hired him to come out again to test pressure on the suction line... All is within specs.

When in operation, the vane often goes into the horizontal position which according to the manual, is "defrosting". This happens, on average, every 10 minutes and lasts around 2 minutes... Give or take. Sometimes, the indoor unit stops blowing and I hear the outdoor unit stop then ramp back up.

I called Ecomfort tech department, who immediately insisted on starting a warranty claim. I just wanted to know if this operation was normal. I was told to contact Mitsubishi directly. However, because I'm not a licensed HVAC technician (even though I'm a licensed contractor), the tech cannot diagnose issues with the unit or tell me if the unit is operating correctly.

Manual claims the outdoor unit is good to -5 degF. Is this normal operation? Are these units just not equipped to operate as heating devices?

 

[PoorOwner]

I purchased a 18,000 BTU Mitsubishi mini-split for my detached 30x30 garage. Installed in September so now, I've been using it for heating whenever I'm occupying the garage. I performed the physical install and I hired a HVAC tech. perform the line-set evacuation and then I hired him to come out again to test pressure on the suction line... All is within specs.

When in operation, the vane often goes into the horizontal position which according to the manual, is "defrosting". This happens, on average, every 10 minutes and lasts around 2 minutes... Give or take. Sometimes, the indoor unit stops blowing and I hear the outdoor unit stop then ramp back up.

I called Ecomfort tech department, who immediately insisted on starting a warranty claim. I just wanted to know if this operation was normal. I was told to contact Mitsubishi directly. However, because I'm not a licensed HVAC technician (even though I'm a licensed contractor), the tech cannot diagnose issues with the unit or tell me if the unit is operating correctly.

Manual claims the outdoor unit is good to -5 degF. Is this normal operation? Are these units just not equipped to operate as heating devices?

I have the same unit and it does the same thing. I think it is not defrosting but it is just turning on and off to maintain the set temperature. Unfortunately the compressor cycles on and off to do so. Because when it turns back on it is blowing very mild like warm air. So it’s not like there is a big heat demand at those times.
Sometimes the fan stop then the vane horizontal and the fan blows again in a few seconds. I have no idea why the fan has to stop for a second because sometimes it does not.
For real defrosting it will also stop, but you then will hear the refrigerant flowing inside the evaporator.

I found if you set it to higher than mid 60s then the blower doesn’t stop completely on the evap, but I can’t get the vane to not go back to horizontal no matter the vane position setting . The idea is that it doesn’t blow cold air on you. It is possible the fan is just running at very very low speed to check the temperature. You can use a flash light to see if the indoor fan is actually spinning.