Gree Ultra Heat GMV-VQ72W/A-F, Service Manual

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Ultra Heat GMV VRF Technical Service Manual_Heat Recovery Serial MAINTENANCE
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Step 3: Check whether the electric expansion valves of ODUs and the 4-way valves act, and
whether the oil return pipes and oil balance valves 1 and 2 are normal. Touch the pipelines next to the
return capillary tubes to check whether there is oil flowing.
Check method for each part:
(1) Electric expansion valve: This valve will reset for each power-on or power-off action. Touch the
valve and you will feel its vibration during the reset action. A crack sound will be heard as well.
Description of electric expansion valve:
(2) Four-way valve: While this valve is normally running, the four copper pipes connected to it will
suffer different temperature. When a unit switches to act the valve, you will feel obvious vibration and
hear sound.