Airwell KXV Series, Engineering Manual

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Engineering manual
227
R410A refrigerant, an error may occur in the refrigeration cycle.)

Use a vacuum pump that has a high vacuum (below -755mmHg) and a large exhaust gas amount (over 40L/minute).

Perform vacuuming for 2 or 3 hours though time differs due to pipe length. In this time, check all packed valves at
liquid, gas and balance sides are fully closed.

If vacuuming valve amount is not decreased to below -755mmHg even after vacuuming for 2 hours or more,
continue vacuuming for 1 hour or more. If -755mmHg or less cannot be obtained by 3 hours or more vacuuming,
detect and repair the leak.

When the vacuuming valve has reached -755mmHg or less after vacuuming for 2 hours or more, close valves VL
and VH on the gauge manifold fully. Stop the vacuum pump, leave it as it is for 1 hour and then check the vacuum
does not change. If it does change then there may be a leak within the system.

After the above procedure for vacuuming has finished, exchange the vacuum pump with a refrigerant cylinder and
advance to the additional charging of refrigerant.
1.4.12 Additional refrigerant charge

After vacuuming work, exchange the vacuum pump with the refrigerant bomb and then start the additional charging
work of refrigerant.

Calculating the amount of additional refrigerant required

When the system is charged with refrigerant at the factory, the amount of refrigerant needed for the pipes on site is
not included. Calculate the additional amount required, and add that amount to the system. Please refer to

Keeping valve of the outdoor unit closed is sure to charge the liquid refrigerant into service port at liquid side.

If the specified amount of refrigerant cannot be charged, open fully valves of outdoor unit at liquid and
discharge/suction gas sides, operate the air conditioner in COOL mode under condition that valve at suction gas side
is a little returned to close side, and then charge refrigerant into service port at suction gas side. In this time, choke
the refrigerant slightly by operating valve of the bomb to charge liquid refrigerant. The liquid refrigerant may be
charged suddenly, therefore be sure to charge refrigerant gradually.

When refrigerant leaks and refrigerant shortage occurs in the system, recover the refrigerant in the system and
recharge refrigerant newly up to the correct level.
Chart 1-28