Mark HCNI 533, Technical Manual

Page: 25 / 84

25
EN
Air purging with vacuum pump:
Pressure Pressu
gauge
(Indoor unit)
(Liquid side)
Two-way valve
Close
(Outdoor unit)
(Gas side)
Three-way valve
Close Gauge manifold
Compound meter
-0.1MPa
Hi Lo
Handle “Lo”
Charge hose
Handle “Hi”
Charge hose
No-return valve
Vacuum pump
Procedure:
1. Tighten the flare nuts of the indoor and outdoor units, and confirm that both the 2-way and
3-way valves are closed.
2. Connect the charge hose with the push pin of Handle “Lo” to the gas service port of the 3-way
valve.
3. Connect another charge hose to the vacuum pump.
4. Fully open the Handle “Lo” manifold valve.
5. Using the vacuum pump, evacuate the system for 30 minutes.
a. Check whether the compound meter indicates -0.1 MPa (14.5 Psi).
• If the meter does not indicate -0.1 MPa (14.5 Psi) after 30 minutes, continue evacuating for
an additional 20 minutes.
• If the pressure does not achieve -0.1 MPa (14.5 Psi) after 50 minutes, check for leakage.
• If the pressure successfully reaches -0.1 MPa (14.5 Psi), fully close the Handle “Lo” valve,
then cease vacuum pump operations.
b. Wait for 5 minutes then check whether the gauge needle moves after turning off the vacuum
pump. If the gauge needle moves backward, check wether there is gas leakage.
6. Loosen the flare nut of the 3-way valve for 6 or 7 seconds and then tighten the flare nut again.
a. Confirm the pressure display in the pressure indicator is slightly higher than the atmospheric
pressure.
b. Remove the charge hose from the 3-way valve.
7. Fully open the 2-way and 3-way valves and tighten the cap of the 2-way and 3-way valves.