Msh-ga50vb trouble

[Harry Trafford]

Hi guys, i was working on the above unit today and found the coil freezing over. When the unit was switched from cooling to off the outdoor would continue to pump cold gas in resulting in the unit freezing up. And wouldn't switch to heating mode every time i changed setting. Also am i right in saying that if the indoor is off i should have no signal voltage to the outdoor???

[Brian_UK]

Don't know the unit but has the 'go' signal relay welded on?

[Harry Trafford]

Its a mitsubishi electric split type unit.

[install monkey]

http://www.aircon-nara.narod.ru/Mits-El/MUH-GA50_60_80VB.pdf
52c contactor in outdoor welded - as brian guessed, take the top lid off the condenser and look at the black thing next to the capacitor- its a non inverter unit with a 12v dc signal on 1,2 terminals, 1 an 3 for reversing valve signal (heating)