Mitsubishi MXZ - 3C24NAHZ2-UI hyper heat heating issue

Duceman

Around 33 degrees and below the unit will go through defrost cycles and in doing so it cannot keep the house at 72 degrees. I was hoping, by purchasing the more expensive hyper heat unit I would have consistent heat into the much lower temperatures. Is this pause in heating and going through a defrost cycle expected below 33 degrees? It does put out heat but not enough when it is no longer a constant heat.

Hot_water_fan

I’d get the installer on the phone - I have a similar unit with no problems. I never notice a defrost even when it’s in the single digits with the thermostat on 72.

pecmsg

Duceman said:

Around 33 degrees and below the unit will go through defrost cycles and in doing so it cannot keep the house at 72 degrees. I was hoping, by purchasing the more expensive hyper heat unit I would have consistent heat into the much lower temperatures. Is this pause in heating and going through a defrost cycle expected below 33 degrees? It does put out heat but not enough when it is no longer a constant heat.

A defrost cycle is needed whenever the outdoor coil is below 32*. That’s roughly 42*F air temperature. The defrost should only last 5 or 7 minutes. 

Sounds like something else is wrong. 

Duceman

When it drops below 32 F we will see the temperature inside drop during the defrost cycle slightly and not be able to recover to the 72 degrees inside. As this continues we gradually are well below the 72 degrees selected on the remote.

Hot_water_fan

It should have no issue recovering from a few minute defrost cycle at 32. Get the installer back out there

Duceman

Thank you for the responses and information. Responding about outside defrost cycle trigger temperature, no defrost cycle until right near 32 F. As far as recovering from that defrost cycle, another question comes up...What temperature should I see coming out of the inside unit following a defrost cycle? Right now if I select 80 F as the desired inside temperature, in order to trigger full fan and heat, I get air at 111 degrees at the mouth of the indoor wall unit (with the current outside temperature of 39 F)