Install Manual

Page 21
mrcool.com
Unit Installation
Pipe diameter (in. | mm) Tightening torque ft/lbs (N·m)
1/4 in | 6.4 mm
3/8 in | 8.3 mm
1/2 in | 12.7 mm
5/8 in | 15.9 mm
3/4 in | 19 mm
7/8 in | 22.2 mm
11-22 ft/lbs (15-30 Nm)
26-30 ft/lbs (35-40 Nm)
33-37 ft/lbs (45-50 Nm)
44-48 ft/lbs (60-65 Nm)
52-55 ft/lbs (70-75 Nm)
59-63 ft/lbs (80-85 Nm)
DO NOT USE EXCESSIVE TORQUE
Excessive force can break the nut or damage
the refrigerant piping. You must not exceed
torque requirements shown in the table.
1. Screw on the flare nut of the flared connecting pipe onto the outdoor unit valve. Refer to Fig. 2.19A &
Fig. 2.19B, using the torque values in the table below.
2. On Model MDUO18024036 & MDUO18048060 plug the knockout holes
shown in Fig. 2.19A with material such as neoprene to prevent small
animals and debris from entering the unit.
Fig. 2.19B
Fig. 2.19A
Refrigerant Line Set
Connection Pipes
Cut Off Valve
Knockout Holes
Conventional Line Set Installation
Pipe Connection
WARNING
Connect the pipe to the unit. Follow all instructions below. Use both a spanner and torque a wrench.
When connecting the tapered flare nut, first apply Polyolester oil (POE oil) on its inner and outer
surface and then screw the flare nut by hand 3 or 4 threads to ensure it does become crooked.
Be sure to connect gas pipe after the liquid pipe is connected.
Confirm the tightening torque by referring to the table below. Then tighten the flare nut to the
specified torque using a torque wrench and spanner. DO NOT over-tighten the flare nut. If the flare
nut is overtightened, it may be damaged and cause leakage.
Keep pipe connection joints exposed to perform the leak test (refer to Post Installation Checks section
of this manual).
If there are no leaks, then apply thermal insulation to the gas piping. Wind sponge around the joint of
the gas pipe and heat insulation sheath on the gas collecting pipe.
Insulation for the liquid piping is optional.
1.
2.
3.
4.
5.
6.
7.
For installation with a No-Vac
®
Quick Connect
®
Line Set, refer to the next section starting on page 24