Mr. Slim

[mr. wilson]

I have been working on a Mitsubishi Mr. slim heat pum that is suck in cooling mode. The reversing valve and coil have been replaced. The unit works in cooling but not in heating mode. I ran the test per service book that tells you to disconnect the compressor, put the unit in emergency mode and check for 208/230 volts at the board after 3 minutes. While performing this test, at the 2 1/2 minute mark, I loose all power to the test points for 2 seconds and then gain it back at (246 volts) for the remaining 30 seconds. the book states that after 3 minutes if there is power to the test points, the valve is bad, and after 3 minutes if there is no power to the test points, the board is bad. It says nothing about loosing power for a second or two. Any help with this problem will be apreciated

[juggalo1018]

Try calling mitsubishi they have a great tech support line for their mini splits.

[cuchulain]

did they run the correct type of wire. I've seen alot of problems due to the wrong wire. I've actually went behind someone and found they ran 18-4 for the control voltage, instead of the required stranded S.O. cable.

[chuckcrj]

Get your post count up and apply for pro membership. You will get more detailed troubleshooting help over there.

Agree with above, call their tech support line. Make sure you have your model and serial numbers handy.