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Owners Manual

ManualsBrandsMRCOOL ManualsAir ConditionersMDUCO180 Universal Series 2 to 3 Ton Cooling Only Condenser Unit with 36000 BTU Cooling Capacity, 3 Connection Types, DC Fan Motor and R410A Refrigerant in Gray
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Page 22
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Unit Installation
Conventional Line Set Installation
Vacuum Lines
WARNING
• Make sure the outlet of the vacuum pump is away from any potential source of fire and is well
ventilated.
• Before vacuum pumping, make sure the unit cut-off valves are closed.
• When vacuum pumping, both the liquid pipe and the gas pipe must be pumped.
1. Remove the caps on the liquid valve, gas valve, and also the service port.
2. Connect the hose at the low pressure and high pressure sides of the manifold valve assembly to the
service port of the unit’s gas and liquid valve. Meanwhile, the gas and liquid valves should be kept closed
to avoid a refrigerant leak.
3. Connect the hose used for evacuation hose to the vacuum pump.
4. Open the switches on the lower pressure side and high pressure side of the manifold valve assembly at
the same time and start the vacuum pump.
5. The evacuation duration typically depends on the unit capacity: for Model MDUCO18024036 time is
generally 30 minutes, for model MDUCO18048060 time is generally 45 minutes. Verify that the
pressure gauge on the low pressure side of the manifold valve assembly reads -0.1 Mp (-30 in Hg). If it
does not, there is leak somewhere. Close the switch fully and stop the vacuum pump.
6. Wait for 10 minutes to see if the system pressure remains unchanged. During this time, the reading of the
pressure gauge at the low pressure side should not be larger than 0.005 Mp (0.15 in Hg).
7. Open the liquid valve slightly, and allow some refrigerant to be released into the connection pipe to
balance the pressure inside and outside of the connection pipe, so that air will not come into the
connection pipe when removing the hose. Note that the gas and liquid valve can be opened fully
only after the manifold valve assembly is removed.
8. Return the caps to the liquid valve, gas valve, and service port.
9. For larger-sized units, there are maintenance ports for the liquid valve and gas valve. During evacuation,
you may connect the two hoses of the branch valve assembly to the maintenance ports to speed up the
evacuation.
Refer to Fig. 2.20
For installation with a No-Vac
®
Quick Connect
®
Line Set, refer to the next section starting on page 24