Century COMFORT-AIRE VMH-SG Series Service Manual page 31

Service Manual - VMHxxSG
Procedure:
1. Tighten the flare nuts of the indoor and outdoor
units, and confirm that both the 2- 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- and 3-way valves and tighten the
cap of the 2- and 3-way valves.
Maintenance 3
 
Maintenance 3